WO2019006849A1

WO2019006849A1 - Method and system for electronic signature

Info

Publication number: WO2019006849A1
Application number: PCT/CN2017/100685
Authority: WO
Inventors: 威廉罗斯科安德鲁; 陈邦道
Original assignee: 克洛斯比尔有限公司
Priority date: 2017-07-07
Filing date: 2017-09-06
Publication date: 2019-01-10

Abstract

Disclosed are a method and system for an electronic signature. The method for an electronic signature comprises allocating a group of secret keys to each user; with regard to each of the secret keys, forming a correlation between the secret key, the publication time of the secret key and a user identifier of the user to which the secret key belongs; hashing the correlation to obtain a Hash value; publishing the Hash value, the publication time and the user identifier on public media before the publication time, wherein the public media can ensure information published thereon cannot be tampered with; and releasing the secret key when the publication time is reached. A quantum computation attack can be resisted by using the technical solution of the disclosure.

Description

Method and system for electronic signature

Cross-reference to related applications

The present disclosure claims the invention entitled "Method and Apparatus for Electronic Signature" filed on July 07, 2017, and the application number of which is filed on Jul. 07, 2017 and entitled "Key Implementation Method and The present application is hereby incorporated by reference in its entirety in its entirety in its entirety in the the the the the the the the the the the the

Technical field

The present invention relates to the field of electronic signature technologies, and in particular, to a method and system for electronic signature, a method for creating a signature, and a method for verifying a signature.

Background technique

With the rapid development of electronic information technology and network technology, people are increasingly transmitting information through the network. In order to ensure the authenticity, validity and integrity of the information transmitted on the Internet, the information transmitted is usually electronically signed. One of the most common and mature implementations of electronic signatures is digital signature technology. Digital signature technology relies on key encryption technology. Existing digital signature technologies mainly include asymmetric cryptography and the like. Asymmetric cryptography is widely used at present. Asymmetric cryptography uses public and private key pairs, taking advantage of the fact that private keys are not easily cracked in polynomial time. However, the advent of quantum computers and the Shor algorithm means that the unbreakable nature of such methods is not secure.

Signature models and asymmetric cryptography that are not susceptible to quantum computing attacks have been studied a lot, but the results have been minimal. Among them, grid-based cryptography seems to be the most promising, but it is still immature.

Therefore, there is a need for a means for electronic signatures that is resistant to quantum computing attacks.

Summary of the invention

In view of the above technical problems, the present disclosure proposes a method and system for electronic signature against quantum computational attacks and a method for creating a signature and a method for verifying a signature.

In one aspect of the invention, a method for electronic signature is provided, comprising: assigning each user a set of keys; for each key, forming the key, the time at which the key was published, and Corresponding relationship between user identifiers of users to which the key belongs; hashing the correspondence to obtain a hash value; before the publishing time, the hash value, the publishing time, and the user identifier Published on public media, wherein the public media can ensure that the information published thereon is not tamperable; and upon receipt of the publication time, the key is released.

In some embodiments, the public medium can be a blockchain.

In some embodiments, the public medium may be a time stamped bulletin board operated by a trusted third party.

In some embodiments, the public medium can be a write-only database, and each data block written to the write-only database is irrevocable and a consensus is reached among all users.

In some embodiments, the hash value published on the public medium, the publication time, and the user identification may be stored in the form of data blocks, and the data blocks have a monotonically increasing timestamp.

In some embodiments, the method for electronic signatures can also include signing the data by the user using a key that has not expired and placing the resulting signature on the public medium.

In some embodiments, the method for electronically signing can also include assigning a timestamp of time 0 to each of the set of keys; and creating another set of keys for the user.

In some embodiments, the creating another set of keys for the user may include dividing a future limited time period into a number of consecutive sub-finite time periods; and creating an announcement time for each sub-limited time period The key within it.

In some embodiments, the creating a key to which the publication time is to be made for each sub-finite period of time may further include: creating a publication time in the sub-state when there is at least one key that has not expired The key within the next sub-limited time period of the finite time period.

In some embodiments, the creating another set of keys for the user may include creating a key to be published at time r+1, r+2, ..., r+2 ^s-1 at time r-1 , where r is the current time and s is rounded to log ₂ r.

In some embodiments, the creating another set of keys for the user further comprises signing the newly created key with a key of the user that has not yet reached the publication time; and placing the resulting signature in the The space used to maintain the key on public media.

In some embodiments, the method for electronically signing can further include dividing a space in the public medium for holding a key into a first portion and a second portion, wherein the first portion is for storing the verified key And signature and the user is only readable and not writable, the second part is for storing unauthenticated keys and signatures and the user is only writable and readable; and the resulting signature is placed in the public The space on the medium for maintaining the key may further comprise writing the obtained signature into the second portion and transferring the resulting signature from the second portion to the first portion after the resulting signature is verified For the user to read.

In some embodiments, the creating another set of keys for the user may also include authenticating the newly created key by a trusted third party.

In another aspect of the invention, a system for electronic signature is provided, comprising a public medium, a trusted third party, and an initializer, wherein: the public medium is configured to ensure that information published thereon is not available Tampering; the trusted third party is configured to authenticate the initializer; and the initializer is configured to: assign each user a set of keys; for each key, form the secret Corresponding relationship between the key, the publication time of the key, and the user identifier of the user to which the key belongs; seeking a hash for the correspondence to obtain a hash value; and prior to the publication time, the hash The value, the published time, and the user identification are posted on the public media.

In some embodiments, the public medium can be a blockchain.

In some embodiments, the public medium may be a time stamped bulletin board operated by the trusted third party.

In some embodiments, the public medium is a write-only database, and each data block written to the write-only database is irrevocable and a consensus is reached among all users.

In some embodiments, the public medium may be further configured to store a signature of the key pair data used by the user using the unpublished time and a key released upon arrival of the publication time.

In some embodiments, the initializer may be further configured to assign a timestamp of time 0 to each key, and the system may further include a key creation module configured to be configured Create another set of keys for the user.

In some embodiments, the key creation module can include a partitioning module configured to divide a future limited time period into a number of consecutive sub-finite time periods; and a first sub-creation module configured to For each sub-limited time period, create a key within which the publication time is to be made.

In some embodiments, the first sub-creation module may be further configured to create a publication time within a next sub-limited time period of the sub-finite time period when there is at least one key that has not expired. Key.

In some embodiments, the key creation module can include a second sub-creation module configured to create at r-1, r+2,...,r at r-1 time +2 ^s-1 time published key, where r is the current time and s is rounded to log ₂ r.

In some embodiments, the key creation module may further include a signature module configured to sign the newly created key with a key of the user that has not yet reached the publication time; and a placement module that is A space is provided for placing the resulting signature on the public medium for holding keys.

In some embodiments, the space in the public medium for holding a key may be divided into a first part and a second part, wherein the first part is for storing the verified key and signature and the user is only readable Not writable, the second portion is for storing unverified keys and signatures and the user is only writable and readable; and the placement module can include a write module configured to a signature written in the second portion; and a transfer module configured to transfer the resulting signature from the second portion to the first portion for reading by the user after the resulting signature is verified .

In some embodiments, the signature module can be further configured to authenticate the newly created key by a trusted third party.

In yet another aspect of the present invention, a method for creating a signature is provided, the method comprising a user selecting a key from a set of keys thereof that has not yet reached a publication time t; signing the data using the selected key; The resulting signature is placed on public media at time t', where t' < t, and the public media can ensure that the information published thereon cannot be tampered with.

In some embodiments, the signing the data using the selected key may further comprise forming a hash (X, A, k), wherein X represents the data, A represents a user identification of the user, and k represents The selected key.

In some embodiments, the signing the data using the selected key may further comprise forming a hash (A, k, X), wherein X represents the data, A represents a user identification of the user, and k represents The selected key.

In some embodiments, the public medium can be a blockchain.

In yet another aspect of the present invention, a method for verifying a signature obtained by a user signing data with a key and having been published on public media at time t' is provided, where t' <t, and t is the publication time of the key, the method comprising verifying that the key is indeed owned by the user; verifying that the key is published at the publication time t of the key; The calculation method calculates the data according to the published key; compares whether the calculated value is equal to the signature; and determines the authenticity of the signature according to the comparison result.

In some embodiments, calculating the data according to the published key according to the calculation manner of the signature may further comprise: calculating a hash (X, A, k) according to the published key, wherein X represents The data, A represents the user identification of the user, and k represents the key.

In some embodiments, the verifying that the key is indeed the user may further include verifying the authenticity of the key; and verifying that the key is published by the user.

In some embodiments, the verifying the authenticity of the key may further comprise verifying the authenticity of the signature of the key published on the public medium.

In some embodiments, the verifying that the key is published by the user may further comprise calculating a hash (k, A, t); determining whether the calculated hash (k, A, t) is equal to the public medium. a hash value corresponding to the key published thereon; and in the case where the judgment result is equal, it is determined that the key is published by the user.

In some embodiments, the public medium can be a blockchain.

In still another aspect of the present invention, a computing device is provided, comprising a processor and a memory, wherein the memory stores computer program instructions that, when executed by the processor, implement as above A method for electronic signature and/or a method for creating a signature and/or a method for verifying a signature.

In still another aspect of the present invention, there is provided a machine readable storage medium having stored thereon computer program instructions, wherein the computer program instructions, when executed by a processor, implement a method for electronic signature as described above And/or methods for creating signatures and/or methods for verifying signatures.

Compared with the prior art, the beneficial effects of the present disclosure are:

First, the technical solution of the present disclosure is to form, for each key, a correspondence between the key, the publication time of the key, and the user identifier of the user to which the key belongs, and the corresponding relationship is The hash value obtained by the hashing, the publication time, and the user identification are posted on the public media on which the information cannot be tampered with. The public medium can ensure that the information published on it cannot be tampered with, and the cryptographic hash function is widely considered to be anti-quantum The attack is calculated, so the technical solution of the present disclosure can be used to resist quantum computing attacks. Moreover, the technical solutions of the present disclosure are capable of operating on systems that are typically inexpensive and insufficient to run asymmetric cryptography methods.

Secondly, since the technical solution of the present disclosure performs only one hash operation in the whole process of signature creation and verification, the present disclosure is used in comparison with asymmetric cryptography and known hash-based schemes and the like. The technical solution password calculation amount is significantly reduced.

Additionally, the technical solution in accordance with the present disclosure can be used to create an equivalent of a public key infrastructure in which the key lifetime is the most important goal.

DRAWINGS

The novel features of the invention are set forth in the appended claims. A better understanding of the features and advantages of the present invention will be obtained in the <RTIgt; The drawings are only for the purpose of illustrating the embodiments and should not be construed as limiting the invention. Throughout the drawings, the same elements are denoted by the same reference numerals, in the drawings:

FIG. 1 shows a flow chart of a method for electronic signature in accordance with an exemplary embodiment of the present invention;

Figure 2 is a flow chart showing an example of creating another set of keys for the user in Figure 1;

3 shows a flow chart of another example of creating another set of keys for the user in FIG. 1;

FIG. 4 shows a schematic diagram of a system for electronic signatures in accordance with an exemplary embodiment of the present invention; FIG.

FIG. 5 is a schematic diagram showing an example of a key creation module in FIG. 4;

FIG. 6 is a schematic diagram showing another example of the key creation module in FIG. 4;

FIG. 7 shows a flowchart of a method for creating a signature in accordance with an exemplary embodiment of the present invention;

FIG. 8 shows a flowchart of a method for verifying a signature in accordance with an exemplary embodiment of the present invention; FIG.

FIG. 9 illustrates a flowchart of an example of verifying that the key is published by the user, in accordance with an exemplary embodiment of the present invention;

FIG. 10 shows a schematic diagram of a computing device in accordance with an exemplary embodiment of the present invention.

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While the exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the invention may be embodied in various forms and not limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be more fully understood, and the scope of the disclosure can be fully conveyed to those skilled in the art. Nothing in the following detailed description is intended to suggest that any particular component, feature or step is essential to the invention. Those skilled in the art will appreciate that various features or steps may be substituted or combined with each other without departing from the scope of the disclosure.

FIG. 1 shows a flow chart of a method for electronic signature in accordance with an exemplary embodiment of the present invention. As shown in FIG. 1, a method for electronic signature can include:

Step S101, assigning a set of keys to each user;

Step S102, for each key, form a correspondence between the key, the publication time of the key, and the user identifier of the user to which the key belongs;

Step S103, performing hashing on the correspondence relationship to obtain a hash value;

Step S104, publishing the hash value, the publication time, and the user identifier on the public media before the publication time, wherein the public media can ensure that the information published thereon is not tamperable;

Step S105, when the publication time is reached, the key is released.

It can be seen from the above that the method for electronic signature according to an exemplary embodiment of the present invention can first assign a set of keys to each user, and form a key, a key announcement for each key in the set of keys. a correspondence between the time and the user identifier of the user to which the key belongs, and then obtaining a hash value of the correspondence, and publishing the hash value, the publication time, and the user identifier on the public media, where The public media can ensure that the information published on it cannot be tampered with. For example, if the key is k, the publication time of the key is t, and the user identifier is A, the corresponding relationship formed is (k, A, t), and published on the public media is (hash(k, A, t), t, A). In addition, the publication time here refers to the time when the key is released, and it can be said that the key is a publicly known time. Since the public medium can ensure that the information published thereon is not tamperable and a suitable key hash function can resist the quantum computer, the method for electronic signature according to an exemplary embodiment of the present invention can be resistant to quantum computing attacks.

As further shown in FIG. 1, the method for electronic signature according to an exemplary embodiment of the present invention may further include a step S106 of signing data by the user using a key that has not reached the publication time and placing the resulting signature on On the public media. A method for electronic signature according to an exemplary embodiment of the present invention first publishes on the public media a hash value, an announcement time, and a user identification of a correspondence relationship with respect to a key, instead of the key itself. Before the announcement time of the key does not come, the user can use the key to sign and sign the pre-sent data and place it on the public media, and the timestamp of the signature is before the announcement time of the key. Initially, before the key was published, the public could not be sure that the data was signed by the user. That is to say, the signature cannot be verified at this time, and the user will release the key when the announcement time of the key arrives, and then the signature can be verified. Therefore, there is a time lag between the signature and the signature being verified. In order for the signature to be verified as soon as possible, the user typically selects the key adjacent to the published time to sign the data. It is usually possible to judge whether the obtained result is the same as the hash value published on the public media by hashing the obtained key, the publication time published on the public media, and the user identification. If the same, the key is This user is all.

In addition, the method for electronic signature according to the exemplary embodiment of the present invention performs only one hash operation in the process of signature and verification, and thus the amount of cryptographic calculation is significantly reduced as compared with asymmetric cryptography or the like.

In some embodiments, the public medium can be a blockchain. The timestamp of the key may be the block index of the block in which the key is published. It is well known that a blockchain is a chained data structure in which data is connected in a time series in a series of blocks, and cryptographically guarantees that the data cannot be tampered and unforgeable distributed books. The blockchain uses encryption techniques such as hashing and signatures, as well as consensus algorithms to build trust mechanisms, so that the cost of repudiation, tampering, and fraud is enormous, ensuring that data cannot be tampered and unforgeable.

In other implementations, the public media may be a time-stamped bulletin board system (BBS) operated by a trusted third party (TTP), that is, guaranteed by a trusted third party. The data published on the BBS cannot be modified. In addition, each piece of data published on the BBS is given a time stamp, and the timestamps are strictly incremented. In still other implementations, the public medium can be a write-only database, and each block of data written to the write-only database is irrevocable and a consensus is reached among all users. The write-only database represents a database to which data can only be written. Consensus indicates that the authenticity of the data written is recognized by all users and has not been tampered with. It will be appreciated that the public medium may be implemented in any manner known in the art, as long as the tamperability and monotonicity of the recording time are guaranteed, the invention is not limited in this respect.

In some embodiments, the hash value published on the public media, the publication time, and the user identification are stored in the form of data blocks, and the data blocks have a monotonically increasing timestamp. In some cases, the block number of the data block can be used as a timestamp. In other cases, the current real time can be used as the timestamp. Those skilled in the art will recognize that other timestamp implementations are also possible.

It can be understood that a set of keys assigned to a user may be a finite set or an infinite set. When the set of keys is a finite set, that is, the number of keys included in the set of keys is limited, and if all the keys in the set of keys have passed the publication time, the user still needs to compare the data. If a signature is made, there will be no key available, because the set of keys assigned to the user at this time has been released, that is, they are already known to the public, and anyone can use them to sign the data. Thus there is no way to determine which user the data came from. When the set of keys is an infinite set, if the time interval between the publication times of the adjacent keys is too large, there may be cases where the signature of the user is not verified, which is not expected. .

Therefore, as shown in FIG. 1, the method for electronic signature according to an exemplary embodiment of the present invention may further include:

Step S107, assigning a timestamp with a time of 0 to each of the set of keys;

Step S108, creating another set of keys for the user, and the other set of keys are respectively to be announced at a corresponding future time.

As can be seen from the above, according to the technical solution of the present disclosure, the set of keys assigned to the user is given a time stamp of time 0 (ie, time 0), and the keys are to be announced at time after time 0, for example. Published at time 1, time 2, time 3, ..., time i, ... and so on. It should be understood that time 1, time 2, time 3, ..., time i, etc. are relative times with respect to time 0. For example, suppose the current time is May 5, 2017. At this time, the time stamp is initially 0 using the technical solution, that is, the current time, May 5, 2017 is regarded as time 0. Assuming that the time interval between two successive times is one day, the time 1 at this time may be May 6, 2017, time 2 is May 7, 2017, and the like. It will be understood by those skilled in the art that the interval between time 1, time 2, time 3, and the like may be in minutes, hours, days, weeks, months, and the like, and the present invention is not limited in this regard. In this context, this set of keys may also be referred to as an initial key, in other words, a key initially assigned to the user. On this basis, another set of keys can be created for the user.

As shown in FIG. 2, a flow chart of one example of creating another set of keys for the user in FIG. 1 is shown. In FIG. 2, creating another set of keys for the user may further include:

Step S201, dividing a future limited time period into a plurality of consecutive sub-finite time segments;

Step S202, for each sub-limited time period, a key in which the publication time is to be created is created.

It can be seen from this that in this example, the finite time period is divided into a finite time period, and then a sub finite time period is used to create a key for a sub finite period of time, that is, to create a key to be advertised in each sub finite period of time. In some cases, a key whose publication time is within the next sub-limited time period of the sub-limited time period may be created when there is at least one key that has not expired. In other cases, a key whose publication time is within the next sub-limited time period of the sub-finite time period may be created when the current time approaches the end of a sub-finite time period, that is, when a sub-finite time period is about to end. Create a key to be published in the next sub-limited time period. Of course, the sub-finite time period can be further subdivided into further sub-finite time periods and the like, and so on, which can be set according to actual needs, and the present invention is not limited in this respect.

FIG. 3 shows a flow chart of another example of creating another set of keys for the user in FIG. 1. As shown in FIG. 3, the step of creating another set of keys for the user may include step S301, creating a secret to be announced at time r+1, r+2, . . . , r+2 ^s-1 at time r ^-1 . Key, where r is the current time and s is rounded to log ₂ r.

Thus, in the example, the key to be published at time 3 is created at time 1; the key to be published at times 5 and 6 is created at time 3; the key to be published at time 7 is created at time 5; Time 7 creates the keys to be published at times 9, 10, and 12; and so on. The key is created in such a way that the time gap between two successive undocumented keys is a power of two. In addition, each time a user uses a newly created key, they can

The length defined by log ₂ t is traced back to the set of keys originally assigned to the user, where t represents the current time. It can be understood that creating another set of keys for the user can be created by the user himself or by a certification authority (CA). A CA is a third-party trusted authority (also known as a trusted third party) that generates and determines digital certificates built on top of a public key infrastructure (PKI), which is intended to be signed and thus enable other users. The new key is valid.

As shown in FIG. 3, the step of creating another set of keys for the user may further include:

Step S302, signing the newly created key with the key of the user that has not yet reached the publication time;

Step S303, placing the obtained signature on the public medium for maintaining the space of the key.

We know that a set of keys initially assigned to a user is authenticated by a trusted third party, so that the authenticity of the set of keys can be guaranteed. In some cases, the newly created key is signed with the key of the user that has not yet reached the publication time, that is, the binding of the newly created key is signed, which can be done, for example, by the newly created key. A combination of information identifying its publication time and the information of its own user is implemented by hashing. It will be appreciated that the signature of the newly created key with the key of the user that has not yet reached the publication time can be implemented by any means known in the art, and the invention is not limited in this respect. Assuming that the key k' is the key originally assigned to the user, and it is to be published at time t', the key k of the publication time t' is used to sign the key k of the publication time t, where t'<t Signing with the key k of the publication time t for the key k" of the publication time t", where t < t", etc. This can be traced back to the initial time 0 for the newly created key. The key, which verifies the authenticity of the newly created key.

However, if all the keys must be traced back to the initial key of time 0 to be verified, it will not be economical in terms of verification time. Therefore, in other embodiments, the newly created key can be authenticated by a trusted third party, in which case the key authenticated by the trusted third party is traced if the signature of the key needs to be verified. Just fine. For example, assume that the key k1 is authenticated by a trusted third party, using the key k1 for the key k2 after the publication time The signature is made, and the key k3 of the publication time t3 is used to sign the key k3 at the publication time t3, where t2 < t3, the key k3 of the publication time t3 is used to sign the key k4 of the publication time t4, where t3 < T4, it is now necessary to verify the signature of the key k4. Therefore, it is first traced back to the key k3 for signing the key k4, which is traced back to the key k2 for signing the key k3, and can be traced back to the key k1 by the key k2. Since the key k1 has been authenticated by a trusted third party, the signature of the key k4 can be verified back to the key k1 without having to trace back to the initial key of time 0.

In some cases, the future key after the publication time of the key k can be signed with any number of publication times using the key k when at least one of the keys k has not yet reached the publication time. These future keys can be populated between the existing keys (ie, the publication time of these future keys can be between the published times of the existing keys), or these future keys can be after the existing keys (ie, the publication time of these future keys is after the publication time of the existing key).

The CA may sign the key of the user (e.g., user A) when at least one key k has not reached the publication time. In such a case, the user A must be able to prove to the CA that the key is indeed owned by it.

In some embodiments, all new signature keys created by the user for themselves or created by a trusted third party such as a CA may be verified by the blockchain consensus protocol. In other words, User A can use the key k' to be published at time t' to sign the key k to be published at time t (where t'<t), resulting in (hash(A,k,t),A , t), ((hash(A,k,t),A,t,k'), ref(k'), where (hash(A,k,t),A,t) is a message, equivalent to one Data X; (hash(A,k,t), A,t,k') is the signature of the data X, ie the calculation of hash(X,A,k'); and ref(k') is the identification of the data X is the new key, refreshing k'. When the key k' is exposed, it can be verified that the data X is issued by user A. Therefore, all users can be at time t', that is, when the key k' has been published. To verify that the key k is the key of User A.

Through the above description, we can know that the user first publishes the hash value, the publication time and the user identification related to the key to the public media, and then announces the key when the announcement time of the key arrives. Verify the signature of the user by using the published key. However, the authenticity of the signed key k cannot be known at this stage. There are two options for verifying the authenticity of a key. One solution is to verify the signature of the key k, verify the key of the signature verifying the key k, etc. until the root authentication location at time 0 is reached. The second option is to verify each key k (and its binding to user A and time t) by the consensus mechanism of the blockchain or a trusted third party of other media once the signature of the key k' is published. Authenticity. In order to achieve this, in one embodiment, the space for holding the key on the public medium (for example, the bulletin board or the blockchain space) is first divided into two parts, a first part and a second part, respectively. The first portion is for storing the verified key and signature and the user is only readable and not writable, and the second portion is for storing the unauthenticated key and signature and the user is only writable and unreadable take. That is, the authenticity of the key stored on the first part has been verified, and the user can read the content on the part but cannot write to the content. The authenticity of the key stored on the second part has not been confirmed, this second part is also referred to as temporary, and the user can only write content to the second part and cannot read content from it. When k _A,t (k _A,t is the key that user A wants to announce at time t) corresponding to the signature stored on the second part at time t, the TTP or consensus protocol can be released according to The signature is verified by k _A,t , and when it is proved that the signature is authentic, the public medium can write the signature (and the key k _A,t ) into the first part. Thus, step 303 in Figure 3 places the resulting signature on the public medium for maintaining the space of the key further comprising: writing the resulting signature into the second portion; and after the resulting signature is verified The resulting signature is transferred from the second portion to the first portion for reading by the user.

FIG. 4 shows a schematic diagram of a system for electronic signatures in accordance with an exemplary embodiment of the present invention. As shown in FIG. 4, a system for electronic signatures can include a public medium 401, a trusted third party (TTP) 402, and an initializer 403, wherein the public medium 401 is configured to ensure publication in The information thereon is not tamperable; the trusted third party 402 is configured to authenticate the initializer; and the initializer 403 is configured to: assign a set of keys to each user; for each a key, forming a correspondence between the key, a publication time of the key, and a user identifier of a user to which the key belongs; obtaining a hash value by hashing the correspondence; and in the publishing The hash value, the publication time, and the user identification are posted on the public media 401 prior to time.

As can be seen from the above, the initializer 403 in the system for electronic signature according to an exemplary embodiment of the present invention can first assign a set of keys to each user and form a key for each of the set of keys. And a correspondence between the publication time of the key and the user identifier of the user to which the key belongs, and then obtaining a hash value of the correspondence, and publishing the hash value, the publication time, and the user identifier in a public On the media 401. For example, if the key is k, the publication time of the key is t, and the user identifier is A, the corresponding relationship formed is (k, A, t), and published on the public media is (hash(k, A, t), t, A). In addition, the publication time here refers to the time when the key is released, and it can be said that the key is a publicly known time. Since the public medium 401 can ensure that the information published thereon is not tamperable and a suitable key hash function can resist the quantum computer, the system for electronic signature according to an exemplary embodiment of the present invention can resist anti-quantum computing attacks. .

For the trusted third party 402, it obtains credible qualifications through legal, administrative, commercial, etc., accepts the supervision of the relevant national administrative department, and provides maintenance and operation services for the system. During the initialization phase, the trusted third party 402 rigorously verifies the identity of each user (eg, offline valid ID, etc.), then generates a set of keys for each authenticated user and provides for those keys, user identities, etc. signature. Other users can verify the signature of the trusted third party 402 at any time. If the verification is passed, other users accept that the key is the user's key.

In some embodiments, the public medium 401 can be a blockchain. The timestamp of the key may be the block index of the block in which the key is published. It is well known that a blockchain is a chained data structure in which data is connected in a time series in a series of blocks, and cryptographically guarantees that the data cannot be tampered and unforgeable distributed books. The blockchain uses encryption techniques such as hashing and signatures, as well as consensus algorithms to build trust mechanisms, so that the cost of repudiation, tampering, and fraud is enormous, ensuring that data cannot be tampered and unforgeable.

In other implementations, the public medium 401 is a time-stamped bulletin board system (BBS) operated by the TTP 402, that is, the TTP 402 guarantees irreversible modification of the data published on the BBS. In addition, each piece of data published on the BBS is given a time stamp, and the timestamps are strictly incremented. In still other implementations, the public media 401 is a write-only database, and each data block written to the write-only database is irrevocable and a consensus is reached among all users. The write-only database represents a database to which data can only be written. Consensus indicates that the authenticity of the data written is recognized by all users and has not been tampered with. It is to be understood that the public medium 401 can be implemented in any manner known in the art, as long as the tamperability and monotonicity of the recording time can be guaranteed, and the present invention is not limited in this respect.

In some embodiments, the hash value published on the public medium 401, the publication time, and the user identification are stored in the form of data blocks, and the data blocks have a monotonically increasing timestamp. In some cases, the block number of the data block can be used as a timestamp. In other cases, the current real time can be used as the timestamp. Those skilled in the art will recognize that other timestamp implementations are also possible.

In addition, the public medium 401 can be further configured to store a signature of the key pair data used by the user using the unpublished time and a key released upon arrival of the publication time. After the key is placed on the public medium 401 by the user, it can be verified whether the key is owned by the user. The system for electronic signature according to the exemplary embodiment of the present invention performs only one hash operation in the process of signature and verification, and thus the amount of cryptographic calculation is significantly reduced as compared with asymmetric cryptography or the like.

Additionally, in some embodiments, the initializer 403 can also be configured to assign a timestamp of time 0 to each key, and these keys are to be published at times after time 0, such as at time 1, time 2 , time 3, ..., time i, ... and so on. It should be understood that time 1, time 2, time 3, ..., time i, etc. are relative times with respect to time 0. For example, suppose the current time is May 5, 2017. At this time, the time stamp is initially 0 using the technical solution, that is, the current time, May 5, 2017 is regarded as time 0. Assuming that the time interval of each time is one day, the time 1 at this time may be May 6, 2017, time 2 is May 7, 2017, and the like. It will be understood by those skilled in the art that the interval between time 1, time 2, time 3, and the like may be in minutes, hours, days, weeks, months, and the like, and the present invention is not limited in this regard.

As further shown in FIG. 4, the system for electronic signatures in accordance with an exemplary embodiment of the present invention may further include a key creation module 404 configured to create another set of keys for the user.

FIG. 5 shows a schematic diagram of one example of the key creation module 404 of FIG. In FIG. 5, the key creation module 404 can include a partitioning module 501 configured to divide a future limited time period into a number of consecutive sub-finite time periods; and a first sub-creation module 502 that is The configuration is used to create a key within which the publication time is to be made for each sub-limited time period. The dividing module 501 divides the finite time period into a sub-finite time period, and then the first sub-creation module 502 creates a key for a sub-finite time period and a sub-finite time period, that is, the creation is to be announced within each sub-limited time period. Key. In some cases, a key whose publication time is within the next sub-limited time period of the sub-limited time period may be created when there is at least one key that has not expired. In other cases, a key whose publication time is within the next sub-limited time period of the sub-finite time period may be created when the current time approaches the end of a sub-finite time period, that is, when a sub-finite time period is about to end. Create a key to be published in the next sub-limited time period. Of course, the sub-finite time period can be further subdivided into further sub-finite time periods and the like, and so on, which can be set according to actual needs, and the present invention is not limited in this respect.

FIG. 6 shows a schematic diagram of another example of the key creation module 404 of FIG. In FIG. 6, the key creation module 404 can include a second sub-creation module 601 configured to create at r-1, r+2, ..., r+2 at r-1 time. The key published at ^s-1 time, where r is the current time and s is rounded to log ₂ r. For example, create a key to be published at time 3 at time 1; create a key to be published at times 5 and 6 at time 3; create a key to be announced at time 7 at time 5; create at time 7 at time Keys published in 9, 10, and 12; and so on.

As further shown in FIG. 6, the key creation module 404 further includes a signature module 602 configured to sign the newly created key with a key of the user that has not yet reached the publication time; and a placement module 603, It is configured to place the resulting signature on the public medium 401 for maintaining the space of the key. Since a set of keys initially assigned to the user is authenticated by the trusted third party 402, the authenticity of the set of keys can be guaranteed. The newly created key can be signed using the user's key that has not yet reached the publication time, for example, assuming that the key k' is the key originally assigned to the user, and it is to be announced at time t', then the publication time t' is used. The key k' is signed for the key k of the publication time t, where t' < t; the key k of the publication time t is used to sign the key k" of the publication time t", where t < t", etc. And so on. This allows the newly created key to be traced back to the key at the initial time of 0, so that the authenticity of the newly created key can be verified.

However, if all the keys must be traced back to the initial key of time 0 to be verified, it will not be economical in terms of verification time. Thus, in other embodiments, the newly created key can be authenticated by the trusted third party 402, in which case, if the signature of the key needs to be verified, it is traced back to the trusted third party 402. The key is fine. For example, assume that the key k1 is authenticated 402 by a trusted third party, the key k1 after the publication time is signed with the key k1, and the key k2 of the publication time t2 is the key k3 of the publication time t3. The signature is made, where t2 < t3, the key k3 of the publication time t3 is used to sign the key k4 of the publication time t4, where t3 < t4, it is now necessary to verify the signature of the key k4. Therefore, it is first traced back to the key k3 for signing the key k4, which is traced back to the key k2 for signing the key k3, and can be traced back to the key k1 by the key k2. Since the key k1 has been authenticated by the trusted third party 402, the signature of the key k4 can be verified back to the key k1 without having to trace back to the initial key of time 0.

The process of creating a key is described in detail below by way of example. It is assumed that the key is initially allocated to the user to publish the time at times 1, 2, 4, 8, 16, and 32. Keys to be published at times 33, 34, 36, 40, 48, and 64 are created at time 31 and signed with a key of time 32, created at time 63 at times 65, 66, 68, 72, 80, The keys published by 96 and 128 are signed with the key of time 64, and the keys to be published at times 129, 130, 132, 136, 144, 160, 192 and 256 are created at time 127 and the key of time 128 is used. They are signed, keys issued at times 193, 194, 196, 200, 208, and 224 are created at time 191 and signed with a key of time 192, and created at time 199 to be at times 201, 202 and 204 announced keys and signed them with a time of 200 key. In order to verify the key of the publication time at time 201, it is necessary to check from the key of the publication time at time 200, the key of time 192, the key of time 128, the key of time 64 to the initial density of the publication time at time 32. A signature chain like a key. It can be seen from this that when the key with the publication time of time N is verified, the inspection chain traced back to the initial key whose time is 1 or above is never longer than ₂ log ₂ N. Such a chain consists of several parts, the first part being the maximum power up to 2 (less than or equal to the maximum power of N), in this case time 128, and the second part being the maximum power from the publication time of 2 The key is published to the initial key and the key with the highest power of time 2 is published.

In some embodiments, the space in the public medium 401 for holding the key can be divided into a first portion and a second portion, wherein the first portion is for storing the verified key and signature and the user is only readable Not writable, the second part is used to store unauthenticated keys and signatures and the user can only write and not read. Additionally, the placement module 603 can include a write module configured to write the resulting signature into the second portion, and a transfer module configured to obtain the resulting signature after verification A signature is transferred from the second portion to the first portion for reading by a user. Therefore, when k _A,t (k _A,t is the key that user A wants to announce at time t) corresponding to the signature stored on the second portion at time t, the public medium 401 (for example, by TTP) The 402 or consensus protocol can verify the signature based on the released k _A,t , and when the signature is verified to be authentic, the public medium 401 can write the signature into the first portion. In this case, since the key stored in the first part has been authenticated by the TTP 402 or the consensus protocol, etc., the verification of the signature chain described in the above paragraph is not required, and the verification of each signature only needs to be performed. Hash once.

As shown in FIG. 7, a flowchart of a method for creating a signature in accordance with an exemplary embodiment of the present invention is shown. In FIG. 7, a method for creating a signature may include:

Step S701, the user selects a key from its key set that has not yet reached the publication time t;

Step S702, signing data using the selected key;

Step S703, the resulting signature is placed on the public medium 401 at time t', where t' < t, and the public medium 401 can ensure that the information posted thereon cannot be tampered with.

It can be seen that the method for creating a signature according to an exemplary embodiment of the present invention can be used by a user to sign data or the like. The user can select a key from his key set that has not yet reached the publication time t, then use the key to sign the data and the like, and place the resulting signature on the public medium 401 at time t'. At this time, the user's signature on the data cannot be verified. When the publication time t of the key is reached, and the key is published, the signature can be verified by using the published key.

In some embodiments, step S702 to sign the data using the selected key may further comprise forming a hash (X, A, k), wherein X represents the data, A represents a user identification of the user, and k represents The selected key, that is, the X, A, and k sequences can be spliced into a string, and the string is hashed to obtain the signature of the data X. In other embodiments, step S702 to sign the data using the selected key may further comprise forming a hash (A, k, X), where X represents the data, A represents the user identification of the user, and k Representing the selected key, that is, A, k, and X can be sequentially spliced into a string, and the string is hashed to obtain the signature of the data X. In still other embodiments, step S702, signing the data using the selected key may further comprise encrypting the data X with the selected key using an encryption algorithm. Those skilled in the art will appreciate that the data may be signed using any method known in the art or known in the future, and the invention is not limited in this respect.

In some embodiments, the public medium 401 can be a blockchain. The timestamp of the key may be the block index of the block in which the key is published. In other embodiments, the public medium 401 is a time stamped bulletin board operated by a trusted third party. In still other embodiments, the public medium 401 is a write-only database, and each data block written to the write-only database is irrevocable and a consensus is reached among all users. It is to be understood that the public medium 401 can be implemented in any manner known in the art, as long as the tamperability and monotonicity of the recording time can be guaranteed, and the present invention is not limited in this respect.

As shown in FIG. 8, there is shown a flowchart of a method for verifying a signature obtained by a user signing data with a key and having been published at time t', in accordance with an exemplary embodiment of the present invention. On the public medium 401, where t' < t, and t is the publication time of the key, the method may include:

Step S801, verifying that the key is indeed owned by the user;

Step S802, verifying that the key is published at the publication time t of the key;

Step S803, calculating the data according to the published key according to the calculation manner of the signature;

Step S804, comparing whether the calculated value obtained is equal to the signature;

Step S805, determining the authenticity of the signature according to the comparison result.

It can be seen from this that the method for verifying a signature according to an exemplary embodiment of the present invention can first verify that the key used for the signature is indeed owned by the user, and then verify that the key has also been published at the claimed time. After the key is published, the data can be calculated with the public key in accordance with the calculation of the signature, and the calculated value is compared with the signature. If they are equal, it can be determined that the signature is true, and if not equal, the signature is not trusted.

In some embodiments, the step S803, according to the calculation manner of the signature, calculating the data according to the published key may further comprise calculating a hash (X, A, k) according to the published key, wherein X represents the data, A represents the user identification of the user, and k represents the key.

In some embodiments, step S801 verifying that the key is indeed the user may further include verifying the authenticity of the key; and verifying that the key is published by the user. In some embodiments, verifying the authenticity of the key may further include verifying the authenticity of the signature of the key published on the public medium 401. Since the key is created using the method for electronic signature described above in the present disclosure, it is assumed that the key k is signed with the key k' preceding it at the time of publication, and the key k' is Signed with the key k" before the time of publication, so that it can be traced back to the key with a timestamp of 0, since the key with a timestamp of 0 is the initial key and is a trusted third party. 402 certified, so the authenticity of the key k can be verified.

In some embodiments, as shown in FIG. 9, an example of verifying that the key is published by the user may further include:

Step S901, calculating hash(k, A, t);

Step S902, determining whether the calculated hash(k, A, t) is equal to a hash value corresponding to the key published on the public medium 401;

In step S903, if the determination result is equal, it is determined that the key is published by the user.

In these embodiments, the key k has been released, ie the publication time t of the key k has been reached, then the hash(k, A, t) can be calculated and the calculated hash(k, A, t) is determined. It is equal to the hash value corresponding to the key k published on the public medium 401. If they are equal, it means that the key k is the key of the user A, so it can be determined that the key k is published by the user A.

In some embodiments, the public medium 401 can be a blockchain. The timestamp of the key may be the block index of the block in which the key is published. In other embodiments, the public medium 401 is a time stamped bulletin board operated by a trusted third party. In still other embodiments, the public medium 401 is a write-only database, and each data block written to the write-only database is irrevocable and a consensus is reached among all users. Understandably, public The media may be implemented in any manner known in the art, as long as the tamperability and monotonicity of the recording time are guaranteed, and the invention is not limited in this respect.

In one aspect of the invention, as shown in FIG. 10, there is also provided a computing device 1000 comprising a memory 1002 and a processor 1001, wherein the memory 1002 stores computer program instructions 10020, the computer program instructions 10020 The method for electronic signature described above and/or the method for creating a signature and/or the method for verifying a signature are implemented when executed by the processor 1001. Since the method for electronic signature, the method for creating a signature, and the method for verifying the signature have been described in detail above, it will not be described in detail herein.

In another aspect of the invention, a machine readable storage medium having stored thereon computer program instructions, wherein the computer program instructions, when executed by a processor, implements the A method of electronic signature and/or a method for creating a signature and/or a method for verifying a signature. The method for electronic signature and/or the method for creating a signature and/or the method for verifying a signature have been described in detail above and will not be described herein. In some embodiments, a machine readable storage medium is a tangible component of a digital processing device. In other embodiments, the machine readable storage medium is optionally removable from the digital processing device. In some embodiments, by way of non-limiting example, the machine readable storage medium may include a USB flash drive, a removable hard disk, a Read-Only Memory (ROM), and a Random Access Memory (RAM). , Flash Memory, Programmable Read Only Memory (PROM), Erasable Programmable Read Only Memory (EPROM), Solid State Memory, Disk, Optical Disk, Cloud Computing System or Services.

It should be understood that the various steps recited in the method embodiments of the present invention can be performed in a different order and/or in parallel. Moreover, method embodiments may include additional steps and/or omit the steps shown. The scope of the invention is not limited in this respect.

In the description provided herein, numerous specific details are set forth. However, it is understood that the embodiments of the present disclosure may be practiced without these specific details. In some embodiments, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of the specification.

While a preferred embodiment of the present invention has been shown and described, it is apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, changes and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of the invention. The scope of the invention is intended to be limited only by the scope of the appended claims and the claims.

Claims

A method for electronic signature, comprising:

Assign a set of keys to each user;

For each key, forming a correspondence between the key, the publication time of the key, and the user identifier of the user to which the key belongs;

Hashing the correspondence to obtain a hash value;

Publishing the hash value, the publication time, and the user identification on public media prior to the publication time, wherein the public medium is capable of ensuring that information published thereon is not tamperable;

Upon reaching the publication time, the key is released.
The method for electronic signature of claim 1 wherein said public medium is a blockchain.
A method for electronic signature as claimed in claim 1 wherein said public medium is a time stamped bulletin board operated by a trusted third party.
The method for electronic signature of claim 1 wherein said public medium is a write-only database and each data block written to said write-only database is irrevocable and a consensus is reached among all users.
A method for electronic signature according to claim 1, wherein said hash value published on said public medium, said publication time, and said user identification are stored in the form of data blocks, and said data blocks have Monotonically increasing timestamp.
The method for electronic signature of claim 1 further comprising signing the data by the user using a key that has not expired and placing the resulting signature on the public medium.
The method for electronic signature according to any one of claims 1 to 6, further comprising:

Assigning a timestamp of time 0 to each of the set of keys;

Create another set of keys for the user.
The method for electronic signature of claim 7 wherein said creating another set of keys for said user comprises:

Dividing a future limited time period into a number of consecutive sub-finite time periods;

For each sub-limited time period, create a key within which the publication time is to be made.
A method for electronic signature according to claim 8, wherein said creating a key within which the publication time is to be made for each sub-limited time period further comprises: when there is at least one key that has not expired And creating a key whose publication time is within the next sub-limited time period of the sub-limited time period.
The method for electronic signature of claim 7 wherein said creating another set of keys for said user comprises:

A key to be published at time r+1, r+2, ..., r+2 s -1 is created at time r -1 , where r is the current time and s is rounded to log 2 r.
A method for electronic signature according to any one of claims 8 to 10, wherein said creating another set of keys for said user further comprises:

Signing the newly created key with the key of the user that has not yet reached the publication time;

The resulting signature is placed on the public medium for the space to hold the key.
A method for electronic signature according to claim 11 further comprising dividing a space in said common medium for holding a key into a first portion and a second portion, wherein said first portion is for storing the verified secret Key and signature and the user is only readable and not writable, the second part is for storing unauthenticated keys and signatures and the user is only writable and not readable;

Placing the resulting signature on the public medium for maintaining the key space further includes:

Writing the obtained signature into the second part;

After the resulting signature is verified, the resulting signature is transferred from the second portion to the first portion for reading by the user.
The method for electronic signature of claim 11 wherein said creating another set of keys for said user further comprises authenticating the newly created key by a trusted third party.
A system for electronic signatures, including public media, trusted third parties, and initializers, where:

The public medium is configured to ensure that information published thereon is not tamperable;

The trusted third party is configured to authenticate the initializer;

The initializer is configured to:

Assign a set of keys to each user;

For each key, forming a correspondence between the key, the publication time of the key, and the user identifier of the user to which the key belongs;

Hashing the correspondence to obtain a hash value;

The hash value, the published time, and the user identification are posted on the public media prior to the publication time.
A system for electronic signature as claimed in claim 14 wherein said common medium is a blockchain.
A system for electronic signature as claimed in claim 14 wherein said public medium is a time stamped bulletin board operated by said trusted third party.
A system for electronic signature as claimed in claim 14 wherein said public medium is a write-only database and each data block written to said write-only database is irrevocable and a consensus is reached among all users.
A system for electronic signature according to claim 14, wherein said hash value published on said public medium, said publication time, and said user identification are stored in the form of data blocks, and said data blocks have Monotonically increasing timestamp.
A system for electronic signature according to claim 14, wherein said public medium is further configured to store a signature of said key pair data used by said user at a time of publication and upon arrival of said publication time The key that was released.
A system for electronic signature according to any one of claims 14 to 19, wherein said initializer is further configured to assign a time stamp of time 0 to each key, and said system further comprises a secret A key creation module configured to create another set of keys for the user.
The system for electronic signature of claim 20, wherein the key creation module comprises:

a partitioning module configured to divide a future limited time period into a number of consecutive sub-finite time periods;

A first sub-creation module configured to create a key within which the publication time is to be made for each sub-finite period of time.
A system for electronic signature according to claim 21, wherein said first sub-creation module is further configured to create an announcement time during said sub-limited time period when there is at least one key that has not expired The key for the next sub-limited time period.
A system for electronic signature according to claim 20, wherein said key creation module comprises a second sub-creation module configured to be created at r-1 time to be at r+1 , r+2,...,r+2 s-1 time published key, where r is the current time and s is rounded to log 2 r.
The system for electronic signature according to any one of claims 21 to 23, wherein the key creation module further comprises:

a signing module configured to sign the newly created key with a key of the user that has not yet reached the publication time; and

A placement module is configured to place the resulting signature on the public medium for maintaining a space for the key.
A system for electronic signature according to claim 24, wherein a space for holding a key in said common medium is divided into a first portion and a second portion, wherein said first portion is for storing a verified key And the signature and the user is only readable and not writable, the second part is for storing the unauthenticated key and signature and the user is only writable and not readable;

The placement module includes:

a write module configured to write the resulting signature into the second portion;

A transfer module configured to transfer the resulting signature from the second portion to the first portion for reading by the user after the resulting signature is verified.
A system for electronic signature as claimed in claim 24 wherein said signature module is further configured to authenticate the newly created key by a trusted third party.
A method for creating a signature, including:

The user selects a key from its key set that has not yet reached the publication time t;

Sign the data with the selected key; and

The resulting signature is placed on public media at time t', where t' < t, and the public media can ensure that the information published thereon cannot be tampered with.
A method for creating a signature as claimed in claim 27, wherein said signing the data using the selected key further comprises forming a hash (X, A, k), wherein X represents said data and A represents said User's user ID, and k indicates the selected key.
A method for creating a signature as claimed in claim 27, wherein said signing the data using the selected key further comprises forming a hash (A, k, X), wherein X represents said data and A represents said User's user ID, and k indicates the selected key.
A method for creating a signature according to any one of claims 27 to 29, wherein the public medium is a blockchain.
A method for creating a signature according to any one of claims 27 to 29, wherein the public medium is a time stamped bulletin board operated by a trusted third party.
A method for creating a signature according to any one of claims 27 to 29, wherein the public medium is a write-only database, and each data block written in the write-only database is irrevocable and available to all users. A consensus has been reached.
A method for verifying a signature obtained by a user signing data with a key and having been published on public media at time t', where t' < t and t is the key The time of publication, the method includes:

Verify that the key is indeed owned by the user;

Verifying that the key is published at the publication time t of the key;

Calculating the data according to the published key according to the calculation manner of the signature;

Comparing whether the calculated value is equal to the signature;

Based on the comparison result, the authenticity of the signature is determined.
The method for verifying a signature according to claim 33, wherein calculating the data according to the published key according to the calculation manner of the signature further comprises:

A hash (X, A, k) is calculated from the published key, where X represents the data, A represents the user identification of the user, and k represents the key.
A method for verifying a signature as claimed in claim 33, wherein said verifying said key is indeed all of said user further comprises:

Verify the authenticity of the key;

Verify that the key is published by the user.
The method for verifying a signature of claim 35, wherein said verifying authenticity of said key further comprises verifying authenticity of a signature of said key published on said public medium.
A method for verifying a signature as claimed in claim 35, wherein said verifying said key is published by said user further comprises:

Calculate hash(k,A,t);

Determining whether the calculated hash(k, A, t) is equal to a hash value corresponding to the key published on the public medium;

In the case where the judgment result is equal, it is determined that the key is published by the user.
A method for verifying a signature according to any one of claims 33 to 37, wherein the public medium is a blockchain.
A method for verifying a signature according to any one of claims 33 to 37, wherein the public medium is a time stamped bulletin board operated by a trusted third party.
A method for verifying a signature according to any one of claims 33 to 37, wherein said public medium is a write-only database, and each data block written in said write-only database is irrevocable and available to all users A consensus has been reached.
A computing device comprising a processor and a memory, wherein the memory stores computer program instructions that, when executed by the processor, implement the use of any one of claims 1 to The method for electronically signing and/or the method for creating a signature according to any one of claims 27 to 32 and/or the method for verifying a signature according to any one of claims 33 to 40.
A machine readable storage medium having stored thereon computer program instructions, wherein the computer program instructions, when executed by a processor, implement the method for electronic signature of any one of claims 1 to 13 and/or Or a method for creating a signature according to any one of claims 27 to 32 and/or a method for verifying a signature according to any one of claims 33 to 40.