WO2023113572A1

WO2023113572A1 - Electronic apparatus and encryption method

Info

Publication number: WO2023113572A1
Application number: PCT/KR2022/020683
Authority: WO
Inventors: 신준범; 홍동연; 성효은; 김규룡
Original assignee: 주식회사 크립토랩
Priority date: 2021-12-17
Filing date: 2022-12-19
Publication date: 2023-06-22

Abstract

Disclosed is an electronic apparatus. The electronic apparatus comprises: memory in which authentication information including a public key is stored; a communication apparatus for communicating with an external apparatus; and a processor that generates a secret key by using a plurality of random keys, and uses the generated secret key to encrypt a message, thereby generating a ciphertext. The processor generates a hybrid ciphertext by using the plurality of random keys, an ID-based public key corresponding to certificate information, and a public key included in the certificate information, and controls the communication apparatus so as to transmit the encrypted message and the generated hybrid ciphertext to the external apparatus.

Description

Electronic Devices and Encryption Methods

The present disclosure relates to an electronic device and an encryption method, and more particularly, to an electronic device capable of performing quantum resistant encryption using a legacy certificate and an encryption method.

Currently issued PKI certificates use legacy cryptographic techniques. Here, PKI (Pubic Key Infrastructure) is a collective term for a set of roles, policies, hardware, software, and procedures used to create, manage, distribute, use, store, and destroy digital certificates and manage public key cryptography.

In this way, since the PKI certificate uses legacy encryption technology, there is a problem in that stability is not guaranteed when a quantum computer comes out.

In order to have quantum tolerance, there must be a certificate for the PQC cryptographic public key, but since PQC standardization has not yet been completed, a certificate with quantum tolerance has not been issued.

Therefore, an encryption method having quantum tolerance has been required even in the existing certificate method until a certificate having quantum tolerance is issued.

Accordingly, the present disclosure is designed to solve the above problems, and relates to an electronic device capable of performing quantum resistant encryption using a legacy certificate and an encryption method.

The present disclosure is to achieve the above object, and an electronic device according to an embodiment of the present disclosure provides a memory for storing certificate information including a public key, a communication device for communicating with an external device, and a plurality of random and a processor generating a secret key using the key and encrypting a message using the generated secret key to generate cipher text, wherein the processor includes the plurality of random keys and an ID-based public key corresponding to the certificate information. and generating a hybrid ciphertext using a public key included in the certificate information, and controlling the communication device to transmit the encrypted message and the generated hybrid ciphertext to the external device.

In this case, the processor may generate a first random key and a second random key, and perform an XOR operation on the first random key and the second random key to generate the secret key.

Meanwhile, the processor encrypts the first random key using the ID-based public key, encrypts the second random key using a public key included in the certificate information, and encrypts the encrypted first random key and Hybrid ciphertext may be generated using the encrypted second random key.

In this case, the processor may encrypt the first random key using a first encryption method and encrypt the second random key using a second encryption method different from the first encryption method.

Meanwhile, the ID-based public key is calculated using an ID generated based on information included in the certificate information, and the ID includes a serial number in the certificate information, a subject unique ID, and an issuer unique ID (Issuer Unique ID).

Meanwhile, the processor may control the communication device to communicate with the external device using Transport Layer Security (TLS).

Meanwhile, the certificate information may be information corresponding to a PKI certificate.

Meanwhile, an encryption method of an electronic device according to an embodiment of the present disclosure includes storing certificate information including a public key, receiving an ID-based public key based on the certificate information from an external device, and generating a plurality of random keys. generating a private key using the generated private key, and generating a cipher text by encrypting a message using the generated private key, the plurality of random keys, an ID-based public key corresponding to the certificate information, and the disclosure included in the certificate information. Generating a hybrid cipher text using a key, and transmitting the encrypted message and the generated hybrid cipher text to the external device.

In this case, in the generating of the ciphertext, the secret key may be generated by generating a first random key and a second random key, and performing an XOR operation on the first random key and the second random key.

Meanwhile, in the generating of the hybrid ciphertext, the first random key is encrypted using the ID-based public key, the second random key is encrypted using a public key included in the certificate information, and the encryption The hybrid ciphertext may be generated using the encrypted first random key and the encrypted second random key.

In this case, in the generating of the hybrid ciphertext, the first random key may be encrypted using a first encryption method, and the second random key may be encrypted using a second encryption method different from the first encryption method.

Meanwhile, a decryption method of an electronic device according to an embodiment of the present disclosure includes storing certificate information including a public key, obtaining an ID-based private key corresponding to the certificate information, and receiving ciphertext and hybrid ciphertext. generating a secret key for the ciphertext using the public key, the ID-based private key, and the hybrid ciphertext; and decrypting the ciphertext using the private key.

In this case, the step of generating the secret key may include each of the encrypted first random key and the encrypted second random key included in the hybrid ciphertext based on the secret key corresponding to the public key included in the certificate information or the ID. Decryption is performed using the secret key, and a secret key may be generated by performing an XOR operation on the first random key and the second random key.

Meanwhile, the ID-based private key is calculated using an ID generated based on information included in the certificate information, and the ID includes a serial number in the certificate information, a subject unique ID, and an issuer unique ID (Issuer Unique ID).

According to various embodiments of the present disclosure as described above, quantum resistant encryption can be performed even using an existing legacy certificate.

The above and other aspects, features, and advantages of the embodiments of the present disclosure will become more apparent from the following description with reference to the accompanying drawings. In the attached drawing:

1 is a diagram for explaining the structure of a network system according to an embodiment of the present disclosure;

2 is a block diagram showing the configuration of an electronic device according to an embodiment of the present disclosure;

3 is a diagram showing an example of information included in a certificate according to an embodiment of the present disclosure;

4 is a diagram for explaining an operation of obtaining an ID private key according to an embodiment of the present disclosure;

5 is a diagram for explaining an encryption operation according to an embodiment of the present disclosure;

6 is a diagram for explaining an encryption method according to an embodiment of the present disclosure, and

7 is a diagram for explaining a decoding method according to an embodiment of the present disclosure.

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Since the present embodiments can apply various transformations and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the scope to the specific embodiments, and should be understood to include various modifications, equivalents, and/or alternatives of the embodiments of the present disclosure. In connection with the description of the drawings, like reference numerals may be used for like elements.

In describing the present disclosure, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present disclosure, a detailed description thereof will be omitted.

In addition, the following embodiments may be modified in many different forms, and the scope of the technical idea of the present disclosure is not limited to the following embodiments. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the spirit of the disclosure to those skilled in the art.

Terms used in this disclosure are only used to describe specific embodiments, and are not intended to limit the scope of rights. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this disclosure, “has,” “may have,” “comprises,” or “may include.” Expressions such as, etc. indicate the presence of a corresponding feature (eg, a component such as a number, function, operation, or part) and do not exclude the presence of additional features.

In this disclosure, expressions such as “A or B,” “at least one of A and/and B,” or “one or more of A or/and B” may include all possible combinations of the items listed together. . For example, “A or B,” “at least one of A and B,” or “at least one of A or B” (1) includes at least one A, (2) includes at least one B, Or (3) may refer to all cases including at least one A and at least one B.

Expressions such as "first," "second," "first," or "second," used in the present disclosure may modify various elements regardless of order and/or importance, and may refer to one element as It is used only to distinguish it from other components and does not limit the corresponding components.

A component (e.g., a first component) is "(operatively or communicatively) coupled with/to" another component (e.g., a second component); When referred to as "connected to", it should be understood that the certain component may be directly connected to the other component or connected through another component (eg, a third component).

On the other hand, when an element (eg, a first element) is referred to as being “directly connected” or “directly connected” to another element (eg, a second element), the element and the above It may be understood that other components (eg, a third component) do not exist between the other components.

The expression “configured to (or configured to)” as used in this disclosure means, depending on the situation, for example, “suitable for,” “having the capacity to.” ," "designed to," "adapted to," "made to," or "capable of." The term "configured (or set) to" may not necessarily mean only "specifically designed to" hardware.

Instead, in some contexts, the phrase "device configured to" may mean that the device is "capable of" in conjunction with other devices or components. For example, the phrase "a processor configured (or configured) to perform A, B, and C" may include a dedicated processor (eg, embedded processor) to perform the operation, or by executing one or more software programs stored in a memory device. , may mean a general-purpose processor (eg, CPU or application processor) capable of performing corresponding operations.

In an embodiment, a 'module' or 'unit' performs at least one function or operation, and may be implemented with hardware or software, or a combination of hardware and software. In addition, a plurality of 'modules' or a plurality of 'units' may be integrated into at least one module and implemented by at least one processor, except for 'modules' or 'units' that need to be implemented with specific hardware.

According to various embodiments, operations performed by modules, programs, or other components may be executed sequentially, in parallel, repetitively, or heuristically, or at least some operations may be executed in a different order, may be omitted, or other operations may be added. can

Meanwhile, various elements and regions in the drawings are schematically drawn. Therefore, the technical spirit of the present invention is not limited by the relative size or spacing drawn in the accompanying drawings.

Meanwhile, an electronic device according to various embodiments of the present disclosure may include, for example, at least one of a TV, a monitor, a projector, a set-top box, a smart phone, a tablet PC, a desktop PC, a laptop PC, or a wearable device. Wearable devices can be accessories (e.g. watches, rings, bracelets, anklets, necklaces, glasses, contact lenses, or head-mounted-devices (HMDs)), textiles or clothing integrals (e.g. electronic garments); It may include at least one of a body-attached circuit (eg, a skin pad or tattoo) or a body-implanted circuit.

In some embodiments, the electronic device may be, for example, a refrigerator, air conditioner, vacuum cleaner, oven, microwave oven, washing machine, air purifier, set top box, home automation control panel, security control panel, media box (e.g. Samsung HomeSync ^™ , Apple TV ^TM , or Google TV ^TM ), a game console (eg, Xbox ^TM , PlayStation ^TM ), an electronic dictionary, an electronic key, a camcorder, or an electronic picture frame. Meanwhile, in the case of implementation, in addition to the above-described examples, if the device includes a display, it may be an electronic device according to the present disclosure.

And, in the present disclosure, “value” is defined as a concept including a vector as well as a scalar value. And in the present disclosure, 'calculate', 'calculate.' Expressions such as, etc. may be replaced by an expression that produces a result of the corresponding calculation or calculation. In addition, unless otherwise stated, an operation for ciphertext to be described later means an isomorphic operation. For example, addition of homomorphic ciphertexts means homomorphic addition of two homomorphic ciphertexts.

Mathematical operations and calculations of each step of the present disclosure described below may be implemented as computer operations by a known coding method and/or coding designed appropriately for the present disclosure to perform the calculations or calculations.

The specific equations described below are illustratively described among possible alternatives, and the scope of the present disclosure should not be construed as being limited to the equations mentioned in the present disclosure.

Hereinafter, with reference to the accompanying drawings, an embodiment according to the present disclosure will be described in detail so that those skilled in the art can easily implement it.

1 is a diagram for explaining the structure of a network system according to an embodiment of the present disclosure.

Referring to FIG. 1 , a network system may include a plurality of electronic devices 100-1 to 100-2, and each component may be connected to each other through a network 10.

The network 10 may be implemented in various types of wired and wireless communication networks, broadcast communication networks, optical communication networks, cloud networks, etc., and each device may be connected in a manner such as Wi-Fi, Bluetooth, NFC (Near Field Communication), etc. without a separate medium. may be

Users can input various information through the electronic devices 100-1 to 100-n they use. The input information may be stored in the electronic devices 100-1 to 100-n themselves, but may also be transmitted to and stored in an external device for storage capacity and security reasons.

When each electronic device 100-1 to 100-n encrypts input information, it can transmit the encrypted information to another electronic device.

Conventionally, it has been common to use a PKI certificate for such encryption. That is, data is encrypted using a public key-based encryption method, but this encryption method has a problem in that stability cannot be corrected when a quantum computer comes out. As technology for quantum computers increases, quantum resistant cryptography, which is described as not being pierced in polynomial time even by quantum computers, has recently been required.

However, since the standardization of PQC to be used for quantum resistant cryptography has not yet been completed, the existing PKI certificate has no choice but to be used.

Considering this point, an object of the present disclosure is to provide an encryption method having quantum tolerance even using an existing PKI certificate (or legacy certificate).

Specifically, in the present disclosure, a secret key for ID-based encryption is generated using an existing PKI certificate, and a quantum resistant secret key is generated using an existing public key and a newly generated private key to perform encryption.

Specifically, it is assumed that the first electronic device 100-1 is a device that performs encryption and the second electronic device 100-2 is a device that performs decryption, as shown in the illustrated example.

In this case, the first electronic device 100-1 and the second electronic device 100-2 may each store certificate information (ie, a PKI certificate). Here, the certificate information may be generated by the second electronic device 100 - 2 or may be generated by a separate key server.

In this situation, the second electronic device 100-2 may request an ID-based public key from the first electronic device 100-1 using the certificate information.

In response to this request, the first electronic device 100-1 may provide the ID-based public key to the second electronic device 100-2. At this time, various unique information included in the aforementioned certificate information may be used as the ID used to generate the ID-based public key. An example of information included in certificate information and a method for generating an ID using the same will be described later with reference to FIG. 3 . Meanwhile, in the above, a method of generating and using an ID-based public key and a corresponding private key based on a public key based on information included in certificate information is described, but a symmetric key method may be used in implementation. In this case, the aforementioned ID-based public key may be referred to as an ID-based private key.

And since each electronic device 100-1 or 100-2 has certificate information, an ID can be generated on the side of the first electronic device 100-1, and on the side of the second electronic device 100-2 can also create If the first electronic device 100-1 generates an ID, the first electronic device 100-1 transmits the generated ID to the second electronic device 100-2, and The device 100-2 may generate an ID-based public key using the received ID. At this time, the ID-based public key may generate an ID-based private key using various algorithms such as lattice-based encryption.

If an ID is generated on the side of the second electronic device 100-2, the first electronic device 100-1 performs public key authentication, generates an ID when public key authentication is completed, and discloses the ID based on the ID. key can be generated.

Also, the first electronic device 100-1 may generate a secret key using a plurality of random keys. For example, the first electronic device 100-1 may generate a first random key and a second random key, and perform an XOR operation on the two random keys to generate a secret key.

In addition, the first electronic device 100 - 1 may generate hybrid encryption text using the received ID-based public key and the public key. For example, the first random key used to generate the secret key is encrypted using the ID-based public key, the public key is used as the second random key, and the encrypted first random key and the second random key are merged to create a hybrid A passphrase can be generated.

When the secret key is generated, the first electronic device 100-1 encrypts the plain text using the corresponding secret key, and transmits the encrypted plain text (ie, cipher text) and the hybrid cipher text to the second electronic device 100-2. can

Meanwhile, the second electronic device 100-2 that has received the cipher text and the hybrid cipher text uses the public key (or private key) included in the received hybrid cipher text and certificate information and the ID-based public key to use the private key used in the cipher text. can be restored, and the ciphertext can be decrypted using the restored private key.

The network system according to the present disclosure can generate ciphertext with quantum resistance even using an existing legacy certificate.

Meanwhile, in the illustration and description of FIG. 1 , although only two electronic devices have been illustrated and described as being included in the network system, three or more electronic devices may be included in implementation. In addition, each of the electronic devices 100-1 and 100-2 is illustrated as being connected only through the network 10, but may be connected through various devices such as a router in implementation.

2 is a block diagram showing the configuration of an electronic device according to an embodiment of the present disclosure.

Referring to FIG. 2 , the electronic device 100 may include a communication device 110, a memory 120, a display 130, a manipulation input device 140, and a processor 150.

The communication device 110 is formed to connect the electronic device 100 with an external device (not shown), and is connected to the external device through a local area network (LAN) and an Internet network, as well as a USB ( A form connected through a Universal Serial Bus) port or a wireless communication (eg, WiFi 802.11a/b/g/n, NFC, Bluetooth) port is also possible. Such a communication device 110 may also be referred to as a transceiver.

The communication device 110 may receive or transmit certificate information and may receive or transmit an ID-based public key generated by another device.

Also, the communication device 110 may receive a message from an external device and transmit the generated encrypted text to the external device.

The memory 120 is a component for storing O/S for driving the electronic device 100, various software, data, and the like. The memory 120 may be implemented in various forms such as RAM, ROM, flash memory, HDD, external memory, memory card, etc., but is not limited to any one.

The memory 120 stores the message to be encrypted (or plain text). Here, the message may be various types of credit information and personal information cited by the user, and may also be information related to use history, such as location information used in the electronic device 100 and Internet usage time information.

Also, the memory 120 may store certificate information and may store intermediate operation results (eg, a quantum resistant secret key, an ID-based public key, etc.) required in a process described later by the electronic device 100 .

And the memory 120 may store the cipher text generated in the process described below. Also, the memory 120 may store encrypted text transmitted from an external device.

The display 130 displays a user interface window for selecting a function supported by the electronic device 100 . Specifically, the display 130 may display a user interface window for selecting various functions provided by the electronic device 100 . The display 130 may be a monitor such as a liquid crystal display (LCD), organic light emitting diodes (OLED), or the like, and may be implemented as a touch screen capable of simultaneously performing the functions of the manipulation input device 140 to be described later. .

The display 130 may display a message in which an encryption target selects a message. Meanwhile, in implementation, the encryption target may be directly selected by the user or may be automatically selected. That is, personal information requiring encryption may be automatically set even if the user does not directly select a message.

The manipulation input device 140 may receive a function selection of the electronic device 100 and a control command for the function from the user. Specifically, the manipulation input device 140 may receive parameters necessary for an encryption operation (or generation of a quantum resistant secret key) from a user. Also, the manipulation input device 140 may receive a message to be encrypted from the user.

The processor 150 controls each component within the electronic device 100 . The processor 150 may be composed of a single device such as a central processing unit (CPU) and an application-specific integrated circuit (ASIC), or may be composed of a plurality of devices such as a CPU and a graphics processing unit (GPU).

The processor 150 receives an ID-based public key from an external device using certificate information. Specifically, the processor 150 may generate an ID using at least one of a public key, a subject unique ID, an issuer unique ID, and a serial number among certificate information. For example, the processor 150 may generate an ID by hashing two or more unique values included in certificate information.

Also, the processor 150 may control the communication device to transmit the generated ID to an external device. Meanwhile, in the above description, the device for encrypting the ciphertext generates the ID, but in implementation, the decryption operation for generating the ID may be performed or the device for generating the key may generate the ID.

And the processor 150 generates a secret key. Specifically, the processor 150 may generate a first random key and a second random key, and perform an XOR operation on the generated first random key and second random key to generate a secret key. Meanwhile, in implementation, a secret key may be generated using various logical operations as well as an XOR operation method, and a secret key may be generated using three or more random keys.

Further, the processor 150 may generate hybrid ciphertext using a plurality of random keys, public keys, and ID-based public keys. Specifically, the processor 150 may encrypt the first random key using the public key, encrypt the second random key using the ID-based public key, and merge the two encrypted random keys to generate hybrid ciphertext. there is. Meanwhile, since different public key encryption schemes are applied in the random key encryption process described above, decryption must be performed with different decryption algorithms in the decryption process.

Also, the processor 150 may control the communication device 110 to transmit the cipher text and the hybrid cipher text to an external device. In this case, the processor 150 may control the communication device 110 to communicate with an external device using Transport Layer Security (TLS).

Meanwhile, hereinafter, an operation when an electronic device performs a decryption operation will be described.

The processor 150 obtains an ID corresponding to certificate information in response to a request from an external device. Since the ID generation method has been described above, redundant description will be omitted. Meanwhile, in the case of implementation, the ID generation operation may be performed by a device that generates a decryption operation or an ID-based public key.

Then, the processor 150 generates an ID-based public key based on the obtained ID and transmits it to an external device. Specifically, the processor 150 may generate an ID-based public key using various ID-based algorithms such as a lattice-based algorithm.

When receiving the hybrid cipher text from an external device, the processor 150 may generate a private key using the hybrid cipher text, certificate information, and ID-based public key. For example, the processor 150 decrypts the first information in the hybrid cryptogram with the first random key using a private key corresponding to the public key included in the certificate information, and uses the ID-based public key to decrypt the second information in the hybrid cryptogram. Information can be decrypted with the second random key. A secret key may be generated by performing an XOR operation on the decrypted first random key and the second random key.

Also, the processor 150 may decrypt the ciphertext using the secret key.

As described above, the electronic device 100 according to the present disclosure can generate a secret key having quantum resistance even using an existing legacy certificate and perform encryption using the secret key, thereby ensuring stability. .

Meanwhile, in the drawings and descriptions of FIGS. 1 and 2, a separate hybrid ciphertext is generated and transmitted to another device together with the ciphertext corresponding to the message, but in the implementation, the ciphertext and the hybrid ciphertext are separately can be sent and received. That is, the hybrid cipher text may be generated in advance and provided to the second electronic device 100 - 2 .

3 is a diagram illustrating an example of information included in a certificate according to an embodiment of the present disclosure.

Specifically, a PKI certificate is a certificate issued electronically by a third party so that the other party to a transaction can verify whether or not the information claimed by the person who signed the electronic signature is true.

These PKI certificates include a variety of information, and information is added as the version increases, as shown. The information included in the PKI certificate is as follows.

This is information indicating the version of the certificate of Version. For example, it may be one of 1, 2, and 3.

Serial Number: A unique serial number assigned to the certificate by the issuing certification authority. This is a number to distinguish the certificate. Since this has a unique value, it can be used for ID generation described later.

Signature Algorithm Identifier: As an item for identifying the algorithm used for signing, for example, it indicates whether an algorithm such as RSA or SHA-1 is used.

Issuer Name: Information indicating the name of the certification authority that issued the certificate.

Validity Period: Indicates the validity period of the certificate.

Subject: Indicates the subject to whom the certificate is issued. For example, it can be a period or an authentication period.

Public Key: Indicates the public key of the certificate owner.

If this is the information included in version 1, the following two pieces of information are added in version 2.

Issuer Unique ID: This is an area that indicates the unique ID of the authentication period that issued the certificate.

Subject Unique ID: This is an area that indicates the unique ID of the subject to whom the certificate was issued.

Version 3 includes an extension area and is used to prevent fraudulent use and to describe additional information.

In this way, since a unique value such as a serial number is described in a certificate, the corresponding serial number can be used as an ID. Meanwhile, in implementation, the ID may be generated using a combination with other information (eg, issuer unique ID or subject unique ID) instead of using only the serial number described above. Also, an ID may be generated by combining an issuer unique ID and a subject unique ID (eg, ID: SUID │IUID).

On the other hand, in FIG. 3, it is illustrated and described as using a standardized certificate, but in implementation, even a non-standardized certificate can be used if the device performing encryption and the device performing decryption can share the form.

4 is a diagram for explaining an operation of obtaining an ID private key according to an embodiment of the present disclosure.

In general, known information can be used as a public key. If the ID is known, the sender of the message can use this value to encrypt it.

However, in order to have quantum resistance, it is necessary to generate a key to enable ID-based encryption rather than using the ID as it is.

To this end, an organization that generates an ID-based public key is required, and when the ID-based public key is generated by an external organization, there is a problem in that the external organization can decrypt the ciphertext.

In addition, a separate channel is required to transmit the ID-based secret key.

To this end, in the present disclosure, data is transmitted and received using TLS as shown in FIG. 4 . Here, the second electronic device 100-2 is illustrated as generating an ID private key, but the second electronic device 100-2 is not a device for decrypting cipher text, but a device for generating a key (ie, a certification authority). device) may be.

First, TLS login may be performed (S410). Specifically, messages transmitted and received in this process support forward secrecy and can use key exchange with quantum tolerance.

And public key authentication can be performed (S4200. In this process, each data can be transmitted and received after being encrypted by TLS.

When public key authentication is performed as described above, the second electronic device 100 - 2 may generate an ID and generate an ID-based public key using the generated ID. Here, the ID generation method can be fixed (or disclosed) so that anyone can calculate it. In addition, when generating an ID, the ID may be generated by including information of the server as well as information included in the above-described certificate (eg, ID: ID ?keyServer).

The generated ID-based public key may be transmitted to the first electronic device 100-1 (S430). Such data can also be transmitted and received after being encrypted with TLS.

5 is a diagram for explaining an encryption operation according to an embodiment of the present disclosure.

Referring to FIG. 5, legacy certificates are shared (S510). Specifically, since a method of sharing an existing PKI certificate is common, a detailed description thereof will be omitted.

Using only the existing information obtained from legacy certificates may reduce reliability. In this regard, in the present disclosure, a hybrid cryptogram (or quantum resistant secret key or hybrid public key) is generated using both the existing public key and the obtained ID-based public key.

Specifically, two random keys may be generated, a secret key may be generated by performing an XOR operation on the two random keys, and cipher text may be generated using the corresponding secret key. In addition, the two random keys may be encrypted with each public key and ID-based public key and provided to the second electronic device 100 - 2 together with the ciphertext (S520).

The second electronic device 100-2 receives the cipher text and the hybrid cipher text, extracts two pieces of information (ie, an encrypted first random key and an encrypted second random key) from the received hybrid cipher text, and extracts the two pieces of information. and the ID-based public key and the private key corresponding to the public key included in the legacy certificate to decrypt the first random key and the second random key, perform an XOR operation on the first random key and the second random key, and perform a secret key ( That is, the secret key used to decrypt the message) can be secured.

If the secret key is secured, the message can be restored using the corresponding secret key (S540).

Meanwhile, although the above-described operation has been described as being used in an encryption process or a decryption process, it may also be used in a signing process when implemented. That is, the above-described ID-based public key may be used as an ID-based signing key, and the above-described hybrid ciphertext may be used as an ID-based authentication key to be used as a signature.

6 is a diagram for explaining an encryption method according to an embodiment of the present disclosure.

First, certificate information including a public key is stored (S610). Meanwhile, such certificate information may be received and stored in advance, and when an encryption method is performed, it may be received and stored from an external device (a key generation server or an electronic device performing a decryption operation) that stores certificate information.

Then, an ID-based public key is received from an external device using the certificate information (S720). Specifically, an ID is generated using at least one of a public key, a subject unique ID, an issuer unique ID, and a serial number among certificate information, and the generated ID is transmitted to an external device to An ID-based public key may be received from an external device. When implemented, an ID can be generated by hashing two or more unique values included in certificate information. In addition, the above-described receiving operation may receive an ID-based public key from an external device using TLS (Transport Layer Security).

Meanwhile, in implementation, an ID may be generated on the side of the above-described external device, and an ID-based public key corresponding to the generated ID may be generated.

When the ID-based public key is received in this way, hybrid cipher text can be generated. Specifically, the secret key may be generated by generating the first random key and the second random key and performing an XOR operation on the generated first random key and the second random key. In addition, the first random key may be encrypted with the ID-based public key, the second random key may be encrypted with the public key, and hybrid ciphertext may be generated using the encrypted two random keys.

Then, the message is encrypted using the private key (S730).

Then, the encrypted message and hybrid ciphertext are transmitted to an external device (S740). Specifically, an encrypted message (ie, cipher text) may be transmitted to an external device using Transport Layer Security (TLS).

Meanwhile, in the illustrated example, hybrid ciphertext is generated during a series of encryption processes, and the generated hybrid ciphertext is shown and described as being transmitted to an external device. It may be performed in advance separately before transmission.

First, certificate information including a public key is stored (S710).

Then, an ID corresponding to the certificate information is acquired (S720). Specifically, in the acquiring of the ID, the ID may be generated using at least one of a public key, a subject unique ID, an issuer unique ID, and a serial number among certificate information. At this time, an ID may be generated by hashing two or more unique values included in the certificate information. Further, in implementation, the corresponding electronic device may not generate the ID, but the device that encrypts the ciphertext may generate the ID and receive the ID generated by the external device to acquire the ID.

Then, an ID-based secret key may be generated based on the obtained ID (S730). For example, in case of using the public key method, an ID-based public key and an ID private key may be generated based on the obtained ID, and the generated ID-based public key may be transmitted to an external device. In the case of a symmetric key method, the generated ID-based secret key can be transmitted to an external device. In this case, an encrypted channel may be used or an ID-based private key may be separately encrypted and transmitted to an external device.

Cipher text and hybrid cipher text are received from an external device (S740). Meanwhile, in implementation, reception of the cipher text and the hybrid cipher text may be performed separately. That is, the hybrid ciphertext may be received and stored in advance.

In addition, the private key applied to the ciphertext can be restored using the hybrid ciphertext, the public key included in the certificate information (or the private key corresponding to the corresponding public key), and the ID-based public key. Specifically, as described above, the hybrid ciphertext is composed of two encrypted random keys. A first random value is decrypted using a secret key corresponding to certificate information, and a second random value is decrypted using an ID-based secret key. can Then, a secret key (or a second secret key) for the cipher text that encrypts the message may be generated by performing an XOR operation on the decrypted first random value and the second random value.

Then, the ciphertext is decrypted using the second secret key (S760). Accordingly, the message can be restored.

Meanwhile, although FIG. 7 shows and describes an ID-based public key generation operation, the above-described operation may be performed in a separate external device (ie, a key server), and the above-described hybrid ciphertext and the corresponding private key The generating operation may have been previously performed prior to receipt of the cipher text.

Meanwhile, methods according to at least some of the various embodiments of the present disclosure described above may be implemented in the form of an application that can be installed in an existing electronic device.

In addition, the methods according to at least some of the various embodiments of the present disclosure described above may be implemented with only a software upgrade or hardware upgrade of an existing electronic device.

Also, methods according to at least some of the various embodiments of the present disclosure described above may be performed through an embedded server included in the electronic device or an external server of at least one of the electronic devices.

Meanwhile, according to an embodiment of the present disclosure, various embodiments described above may be implemented as software including instructions stored in a machine-readable storage medium (eg, a computer). A device is a device capable of calling a stored command from a storage medium and operating according to the called command, and may include an electronic device (eg, the electronic device A) according to the disclosed embodiments. When executed by this processor, the processor may directly or use other components under the control of the processor to perform a function corresponding to the instruction, and the instruction may include code generated or executed by a compiler or an interpreter. A device-readable storage medium may be provided in the form of a non-transitory storage medium, where a 'non-transitory storage medium' is a tangible device and a signal (e.g. : electromagnetic waves), and this term does not distinguish between cases in which data is stored semi-permanently and temporarily stored in storage media. For example, 'non-temporary storage media' means that data is temporarily stored. According to an embodiment, the method according to various embodiments disclosed in this document may be provided by being included in a computer program product, which is a product that is a seller and a buyer. The computer program product is distributed in the form of a device-readable storage medium (eg compact disc read only memory (CD-ROM)), or through an application store (eg Play Store™) or Distributed (eg, downloaded or uploaded) online, directly between two user devices (eg, smartphones) In the case of online distribution, a computer program product (eg, a downloadable app) At least a part of may be at least temporarily stored in a device-readable storage medium, such as a manufacturer's server, an application store server, or a relay server memory, or may be temporarily generated.

Various embodiments of the present disclosure may be implemented as software including commands stored in a storage medium readable by a machine (eg, a computer). The device calls the stored commands from the storage medium. And, as a device capable of operating according to the called command, it may include an electronic device (eg, the electronic device 100) according to the disclosed embodiments.

When the above-described command is executed by a processor, the processor may perform a function corresponding to the above-described command by using other components directly or under the control of the above-described processor. An instruction may include code generated or executed by a compiler or interpreter.

Although the preferred embodiments of the present disclosure have been shown and described above, the present disclosure is not limited to the specific embodiments described above, and is common in the art to which the disclosure belongs without departing from the gist of the present disclosure claimed in the claims. Of course, various modifications are possible by those with knowledge of, and these modifications should not be individually understood from the technical spirit or perspective of the present disclosure.

Claims

In electronic devices,

a memory for storing certificate information including a public key;

a communication device that communicates with an external device; and

A processor for generating a secret key using a plurality of random keys and encrypting a message using the generated secret key to generate cipher text;

the processor,

A hybrid ciphertext is generated using the plurality of random keys, an ID-based private key corresponding to the certificate information, and a public key included in the certificate information, and the encrypted message and the generated hybrid ciphertext are transmitted to the external device. An electronic device that controls the communication device to do so.
According to claim 1,

the processor,

An electronic device generating the secret key by generating a first random key and a second random key, and performing an XOR operation on the first random key and the second random key.
According to claim 1,

the processor,

The first random key is encrypted using the ID-based public key, the second random key is encrypted using the public key included in the certificate information, and the encrypted first random key and the encrypted second random key are encrypted. An electronic device that uses a key to generate hybrid ciphertext.
According to claim 3,

the processor,

An electronic device that encrypts the first random key using a first encryption method and encrypts the second random key using a second encryption method different from the first encryption method.
According to claim 1,

The ID-based public key is calculated using an ID generated based on information included in the certificate information,

The electronic device of claim 1 , wherein the ID is generated using at least one of a serial number, a subject unique ID, and an issuer unique ID in the certificate information.
According to claim 1,

the processor,

An electronic device that controls the communication device to communicate with the external device using Transport Layer Security (TLS).
According to claim 1,

The certificate information is information corresponding to a PKI certificate.
In the encryption method of an electronic device,

storing certificate information including a public key;

Receiving an ID-based public key based on the certificate information from an external device;

generating a secret key using a plurality of random keys and encrypting a message using the generated secret key to generate cipher text;

generating hybrid ciphertext using the plurality of random keys, an ID-based public key corresponding to the certificate information, and a public key included in the certificate information; and

and transmitting the encrypted message and the generated hybrid ciphertext to the external device.
According to claim 8,

The step of generating the ciphertext is,

An encryption method comprising generating a first random key and a second random key, and performing an XOR operation on the first random key and the second random key to generate the secret key.
According to claim 8,

Generating the hybrid ciphertext,

The first random key is encrypted using the ID-based public key, the second random key is encrypted using the public key included in the certificate information, and the encrypted first random key and the encrypted second random key are encrypted. An encryption method that uses a key to generate a hybrid ciphertext.
According to claim 10,

Generating the hybrid ciphertext,

An encryption method of encrypting the first random key using a first encryption method and encrypting the second random key using a second encryption method different from the first encryption method.
According to claim 8,

The certificate information is information corresponding to a PKI certificate.
In the decoding method of the electronic device,

storing certificate information including a public key;

obtaining an ID-based private key corresponding to the certificate information;

receiving a ciphertext and a hybrid ciphertext;

generating a secret key for the ciphertext using the public key, the ID-based private key, and the hybrid ciphertext; and

Decrypting the ciphertext using the secret key; decryption method comprising a.
According to claim 13,

Generating the secret key,

Each of the encrypted first random key and the encrypted second random key included in the hybrid ciphertext is decrypted using a private key corresponding to a public key included in the certificate information or the ID-based private key, and the first random key and performing an XOR operation on the second random key to generate a secret key.
According to claim 13,

The ID-based private key is calculated using an ID generated based on information included in the certificate information,

The ID is generated using at least one of a serial number, a subject unique ID, and an issuer unique ID in the certificate information.