KR20190027572A - Method for generating One-Time Password - Google Patents

Abstract

Provided is a method for generating a one-time password that prevents an unauthorized use of OTP by providing a method to dynamically change the seed value so that a seed value can not be returned to the past through time manipulation. The provided method is a method for generating, in a terminal, a i^th (i is same or bigger than one) one-time password comprising the steps of: generating a i^th seed value through an arithmetic f-function based on a time at which a i^th one-time password is generated, a time at which a previous one-time password was generated, and a seed value at which the previous one-time password was generated; and generating a i^th one-time password from the i^th seed value, wherein the arithmetic f-function consists of a monotone function with properties of monotone increasing or monotone decreasing.

Description

How to Generate a One-Time Password {Method for generating One-Time Password}

The present invention relates to a method of generating a one-time password, and more particularly, to a method of generating a one-time password used in a security system or the like.

One-Time Password (OTP) is intended to prevent password stealing problems that can occur as a result of repeated reuse of the same password.

Various methods such as a query / response method, a time synchronization method, an event synchronization method, and the like are known as methods for generating the one-time password (OTP).

The query / response method is the most secure and effective, but it only works in an environment where communication between the terminal generating the OTP and the server to be verified must be performed, which makes it difficult to use in the closed network. Also, if not, there is a vulnerability to generate OTP by inputting the query value in advance.

Usually, the time synchronous method or the event synchronous method is mainly used. In the case of the event synchronous method, event manipulation is too slow and is generally used together with the time synchronous method rather than alone.

On the other hand, in the case of the time synchronization method, the seed value is shared between the terminal and the server, and the terminal and the server verify and validate the generated OTP by synchronizing with the time, respectively. It is widely known that such a time synchronization method has a problem that OTP is leaked in advance when the synchronization element, the time, is manipulated. Due to these problems, mobile (smartphone) OTP that uses mobile (smart phone) as a terminal always has a problem of poor security.

Assuming this vulnerability is used as an attack point, the following problems arise. After changing the view of mobile (smartphone) to 7 days or later, for example, the OTP is generated and notified to the third party accomplice. After that, if you create your own alibi on the 7th day and you commit the crime using the OTP already received by the third party co-worker, you can get rid of the crime.

Prior Art 1: Korean Patent No. 10-1316605 (Method of Generating Disposable Password of Cryptographic Algorithm Using N-BOX) Prior Art 2: Korean Patent Publication No. 10-2011-0054701 (Graphic Mobile OTP generation and authentication system and method) Prior Art 3: Korean Patent Registration No. 10-1268289 (OTP key generation module using voice, method of generating and communication device using the same) Prior Art 4: Korean Patent No. 10-1671463 (OTP generation and authentication system, and OTP generation and authentication method using the same)

Disclosure of Invention Technical Problem [8] The present invention has been proposed in order to solve the above-mentioned problems of the related art, and it is an object of the present invention to provide a method of dynamically changing a seed value, The present invention has been made in view of the above problems.

According to another aspect of the present invention, there is provided a method of generating a disposable password in a terminal, the method comprising the steps of: generating i-th one- Generating an i-th seed value through a computation f-function based on a time at which the previous one-time password was generated and a seed value at which the one-time password was generated; And generating the i-th disposable secret code from the i-th seed value, wherein the calculation f-function comprises a monotone function having monotone increasing or monotonic decreasing properties.

And after the generation of the i-th seed value, deleting the time at which the immediately preceding seed value and the immediately preceding one-time password were generated, and storing the i-th seed value and time.

Meanwhile, a method of generating a one-time password according to another embodiment of the present invention is a method of generating i (i> = 1) th one-time password at a terminal, comprising: receiving a query from a server; Receiving a response value for the query from a user; Generating an i-th seed value through a computation f-function based on a time at which the i-th one-time password is generated, a time at which the one-time password was generated at the immediately preceding time, and a seed value at which the one-time password was generated; And generating the i-th disposable secret code from the i-th seed value and the response value, wherein the calculation f-function comprises a monotone function having monotone increasing or monotone decreasing properties.

According to the present invention having such a configuration, the time manipulation in the terminal is possible only in the future but not in the past.

If the time already manipulated in the future is returned to the previous time, the OTP will not operate (verification fails in the server).

The usual crime is done with the third partner rather than alone, and the alibi is necessary. By not letting the time be turned to the past, it prevents the party from forming an alibi, preventing the OTP from being used negatively (for example, as a crime). In particular, there is an effect that a mobile (smart phone) having a relatively easy visual operation can be used more universally as an OTP terminal.

In addition, in the case of inputting a response value for a query according to the present invention, in order to calculate OTP in advance, all response values must be inputted, and the processing time must be reversed and processed. In this case, The problem is that the normal OTP is not generated and the OTP can not be used for a negative purpose.

1 is a flowchart illustrating a method of generating a disposable password according to an embodiment of the present invention.
2 is a block diagram of the terminal employed in the flowchart of FIG.
3 is a graph employed in the flowchart of FIG.
4 is a flowchart illustrating a method of generating a disposable password according to another embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

(Explanation of Examples of the Present Invention)

A method of generating a one-time password according to an embodiment of the present invention is performed in a terminal (not shown). UE share the first seed value S ₀ and the first time T ₀ and the terminal (not shown).

For example, the terminal may be implemented as a portable terminal or a portable computer. Here, the portable terminal is a wireless communication device that is guaranteed to be portable and mobility, and can be used as a personal communication system (PCS), a global system for mobile communications (GSM), a personal digital cellular (PDC), a personal handyphone system (PHS) Handheld devices such as a handheld device, an assistant, an IMT (International Mobile Telecommunication) -2000, a Code Division Multiple Access (CDMA) -2000, a W-CDMA ) Based wireless communication devices. The portable computer may include a notebook, a laptop, and the like. In addition, the terminal may be a smart device such as a smart phone, a smart note, a tablet PC, a wearable computer, or the like.

As described above, the embodiment of the present invention is a method for generating an OTP in an OTP generation program of a terminal (not shown) sharing a first seed value S ₀ and an initial time T ₀ with a server (not shown) = 1) th OTP is generated.

One-time password generation according to an embodiment of the present invention, at the time that created the i-th time T _i for generating the OTP OTP just before (i.e., OTP _i-1) T _{i -1} and just before the OTP (i.e., OTP _{i- 1} ) th seed value S _i through a function f (S _{i -1} , T _i , T _{i -1} ) based on the seed value S _{i -1} that has generated the seed value S _{i -1} ; And generating an i-th OTP from the i-th seed value S _i .

At this time, it is preferable that the calculation f function is composed of a monotonic function having the property of monotonous increase or monotonic decrease.

After generating the i-th seed value S _i , the terminal deletes the immediate seed value S _{i -1} and the time T _{i -1} at which the immediately-preceding OTP was generated, and stores the i-th seed value S _i and the time T _i .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a flowchart for explaining a method of generating a one-time password according to an embodiment of the present invention, FIG. 2 is a configuration diagram within a terminal employed in the flowchart of FIG. 1, It is a graph employed.

In order to generate i (i> = 1) th OTP, i-th seed value S _i should be generated first.

To this end, the embodiment just before the i-th time T _i and generating the OTP OTP of the present _invention generates a time T _i which generate (i. E., OTP _{i 1) -1} and just before the OTP (i.e., OTP _i-1) seed value to generate the i-th seed value S _i by the operation _{f (S i -1, T i} , T i -1) function that the S _{i -1} based on (S10) did. At this time, the arithmetic f-function is composed of monotonic functions having monotone increasing or monotonic decreasing properties.

The above-described step S10 will be described in more detail as follows.

All binary data can be represented by numbers. For ease of understanding, the seed value or time is represented by a simple number.

It is assumed that the initial seed value S ₀ is 1000 and the initial time T ₀ is 10.

The time T ₁ at the time when the time has passed by 30 will be 40. Here, the mathematical operation is a function that applies _{f = S i -1 + | -} | defined by T _i T _{i -1} if (| | a = the absolute value of a), the function f is a monotonically increasing function, S ₁ = 1000 + | 40 - 10 | = 1030.

Hereinafter, it is assumed that the user manipulates the time and reverts to -10. The time of returning by -10 from the original is increased by 20 from T ₀ to 30. Accordingly, S ₂ = 1000 + | 30 - 10 | = 1020 should be normal.

However, in the embodiment of the present invention, when the value of S ₂ is used, since the seed value S ₁ and time T ₁ generated immediately before are used, S ₂ = 1030 + | 30-40 | = 1040, resulting in an abnormal seed value. As a result, when the user manipulates and manipulates the time, an abnormal seed value is obtained. If, the operational function f = f S _{i -1} + a _{(T i - 1 - T i} ) of the above when used with _{S 2 = 1030 + (30-40)} = 1020 is the return to normal time is also the seed value Respectively. In the embodiment of the present invention, the reason why the arithmetic f-function is a monotone increasing function or a monotone decreasing function is to make it impossible to generate a normal seed value when the time is reversed.

In other words, in the embodiment of the present invention, in order to generate an abnormal seed value when the user manipulates the time and returns to the past, a calculation function f = S _{i -1} + | T _i - T _{i -1} | Increment function or monotone decreasing function is used. In Fig. 2, reference numeral 10 denotes a seed value generator. As shown in FIG. 2, the seed value generator 10 calculates a seed value and a time immediately before the current seed value is to be obtained by dividing the seed value and the time immediately before the current seed value into a single value such as a function f = S _{i -1} + | T _i - T _{i -1} | The current seed value is obtained through an increasing function or a monotone decreasing function.

Then, the terminal stores the current seed value and time generated by the monotone function having the property of forging increase or forging reduction. This is because it is necessary to know the updated seed value in order to generate the succeeding seed value normally. That is, when the i-th seed value S _i is generated, the terminal deletes the immediately preceding seed values S _{i -1} and T _{i -1} , and stores the i-th seed value S _i and the time T _i in a memory (not shown). In FIG. 2, for example, if the seed value S ₁ is obtained, the immediately preceding seed values S ₀ and T ₀ are deleted, and the seed values S ₁ and T ₁ are stored.

In addition to the above absolute value calculation, there are various functions that are monotone increasing or monotone reducing such as a square expression (( _Ti - _{Ti - 1} ) ² ).

On the other hand, the seed value S _i may be expressed in a form including the cumulative change (Σ _{i> = 1} | T _i -T _{i -1} |) by the time difference while maintaining the initial seed value S ₀ have. That is, it may be in the form of S _i = S ₀ + (Σ _{i> = 1} | T _i -T _{i -1} |). At this time, S ₀ and the cumulative minute in place of _{S i (Σ i> = 1} | T i -T i-1 |) may take the form of a store.

Thus, the i-th seed value is generated after the S _i, and generates the i (i> = 1) th from the OTP generated by the i-th seed value S _i (S20). 2, reference numeral 20 denotes an OTP generation function unit. The OTP generation function unit 20 can use various known OTP generation functions such as a hash function or a symmetric key encryption function. After all, in order to produce a i (i> = 1) th from the OTP generated by the i-th seed value S _i and inputs the generated seed value S _i i-th to the OTP generation function unit 20. The Accordingly, the OTP generation function unit 20 generates i (i> = 1) OTP based on the i-th seed value S _i and the OTP generation function.

However, as described above, if the user manipulates the time and returns the abnormal seed value, an abnormal OTP will be obtained if the i-th OTP is generated based on the abnormal seed value. Accordingly, if the abnormal i-th OTP is transmitted to the server (not shown), the server will fail verification.

As shown in FIG. 3 (a), the graph of the monotone increasing function is geometrically ascending from left to right as shown in FIG. 3 (a), and the graph of the monotone decreasing function is the form of falling from left to right as shown in FIG. will be. However, an example of a graph of a function excluding the monotone increasing function and the monotone decreasing function may be the same as that of FIG. 3 (c). 3, T represents time, and S represents a seed value. In FIGS. 3 (a) and 3 (b), the same time does not exist during the relevant time even if a certain amount of time elapses. 3 (c), the seed values S are different from each other at points P1, P2, P3, and P4 (assuming P1, P2, P3, and P4 exist on the same horizontal line) There is a point where this happens. In other words, if the function of the form as shown in FIG. 3 (c) is employed, the user can operate the same time when the time is returned to the past, so that the OTP can be generated irregularly. However, if the monotone increasing function or the monotone decreasing function as shown in FIG. 3 (a) or (b) is used, the user can not manipulate the time at the same time even if the time is returned to the past, .

As described above, according to an embodiment of the present invention, an i-th seed value is generated using a computational f-function composed of a monotone function having monotone increasing or monotonic decreasing properties, and the i-th seed value is generated using the i- OTP. At this time, if the user manipulates the time and returns to the past, the abnormal fuzzy seed value and the abnormal OTP are obtained through the operation f function having the monotone increasing function or the monotone decreasing function. This makes it possible to prevent an unauthorized use of the OTP.

(Explaining another embodiment of the present invention)

A method of generating a one-time password according to another embodiment of the present invention is performed in a terminal (not shown). Terminal is shared with the first seed value S ₀ and T ₀ the first time server (not shown).

For example, the terminal may be implemented as a portable terminal or a portable computer. Here, the portable terminal is a wireless communication device that is guaranteed to be portable and mobility, and can be used as a personal communication system (PCS), a global system for mobile communications (GSM), a personal digital cellular (PDC), a personal handyphone system (PHS) Handheld devices such as a handheld device, an assistant, an IMT (International Mobile Telecommunication) -2000, a Code Division Multiple Access (CDMA) -2000, a W-CDMA ) Based wireless communication devices. The portable computer may include a notebook, a laptop, and the like. In addition, the terminal may be a smart device such as a smart phone, a smart note, a tablet PC, a wearable computer, or the like.

As described above, another embodiment of the present invention is a method for generating an OTP in an OTP generation program of a terminal (not shown) sharing a first seed value S ₀ and an initial time T ₀ with a server (not shown) > = 1) th OTP is generated.

A method of generating a one-time password according to another embodiment of the present invention includes: receiving a query from a server (not shown); Receiving a response value for a query from a user; time of generating the i-th OTP T _i and the immediately preceding OTP (i.e., OTP _i-1) which generates a time T _{i -1} and just before the OTP (i.e., OTP _i-1) based on the seed value S _{i -1} that generated the Generating an _{i &lt}; _th > seed value S _i through a function f (S _{i -1} , T _i , T _{i -1} ) And generating an i-th OTP from the i-th seed value S _i and the response value.

At this time, it is preferable that the calculation f function is composed of a monotonic function having the property of monotonous increase or monotonic decrease.

After generating the i-th seed value S _i , the terminal deletes the immediate seed value S _{i -1} and the time T _{i -1} at which the immediately-preceding OTP was generated, and stores the i-th seed value S _i and the time T _i .

Hereinafter, another embodiment of the present invention will be described in detail with reference to the drawings.

4 is a flowchart illustrating a method of generating a disposable password according to another embodiment of the present invention.

First, the terminal receives a predetermined query from the server (S100). For example, the query may be a request such as " Please input each of the values described in the first and ten in the security card ".

Accordingly, the terminal displays the received query on the screen (S110). Since the terminal may be implemented as a portable terminal or a portable computer, or may be a smart device such as a smart phone, a smart note, a tablet PC, a wearable computer, and the like, a display unit (not shown) .

Then, the user confirms the values described in No. 1 and No. 10 in the security card, and then inputs them (S120). Here, the value input by the user can be referred to as a response value to the query. The terminal temporarily stores the response value from the user.

Then, the terminal generates an OTP at the present time (e.g., i-th).

In order to generate i (i> = 1) th OTP, i-th seed value S _i should be generated first.

To this end, a further embodiment is the i-th time T _i and the OTP OTP just before (i.e., OTP _i-1) which generates a time T _{i -1} and just before the OTP (i.e., OTP _i-1) for generating the present invention The _i- th seed value S _i is generated through a function f (S _{i -1} , T _i , T _{i -1} ) based on the generated seed value S _i-1 (S130). At this time, the arithmetic f-function is composed of monotonic functions having monotone increasing or monotonic decreasing properties.

A more detailed description of step S130 described above is replaced with a more detailed description of step S10 described in the embodiment of the present invention.

Thus, after creating the i-th seed value S _i is, and generates the i (i> = 1) th OTP generated from a seed value S _i i-th and the response value (S140). After all, a i (i> = 1), the i-th generated in order to generate a second OTP seed value S _i and the response value from the generated i-th seed value S _i and response values input to the OTP generation function unit 20. The Accordingly, the OTP generation function unit 20 generates i (i> = 1) OTP based on the i-th seed value S _i , the response value, and the OTP generation function.

However, as described above, if the user manipulates the time and returns the abnormal seed value, an abnormal OTP will be obtained if the i-th OTP is generated based on the abnormal seed value. Accordingly, if the abnormal i-th OTP is transmitted to the server (not shown), the server will fail verification.

As described above, according to another embodiment of the present invention, an i-th seed value is generated using a computation f-function composed of a monotone function having monotone increasing or monotone decreasing properties, and the i-th seed value and the To generate the i-th OTP. At this time, if the user manipulates the time and returns to the past, the abnormal fuzzy seed value and the abnormal OTP are obtained through the operation f function having the monotone increasing function or the monotone decreasing function. This makes it possible to prevent an unauthorized use of the OTP.

In addition, even if a user inputs a wrong response value for a query, an abnormal OTP will be generated, so the server recognizes it as an unauthorized use and fails the verification. This makes it possible to prevent an unauthorized use of the OTP.

Also, the above-described one-time password generation method of the present invention can be implemented as a computer-readable code on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like. In addition, the computer-readable recording medium may be distributed over network-connected computer systems so that computer readable codes can be stored and executed in a distributed manner. And, functional programs, codes and code segments for implementing the above method can be easily inferred by programmers of the technical field to which the present invention belongs.

As described above, an optimal embodiment has been disclosed in the drawings and specification. While specific terms have been employed herein, they are used for the purpose of describing the invention only and are not used to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: seed value generator
20: OTP generation function section

Claims (4)

A method for generating i (i> = 1) th disposable passwords in a terminal,
Generating an i-th seed value through a computation f-function based on a time at which the i-th one-time password is generated, a time at which the one-time password was generated at the immediately preceding time, and a seed value at which the one-time password was generated; And
And generating the i-th disposable secret code from the i-th seed value,
Wherein the operation f function is a monotone function having a property of monotone increase or monotone decrease. The method according to claim 1,
And after the generation of the i < th > seed value, deleting the time at which the immediately preceding seed value and the immediately preceding one time password are generated, and storing the i < th > seed value and time. How to create a password. A method for generating i (i> = 1) th disposable passwords in a terminal,
Receiving a query from a server;
Receiving a response value for the query from a user;
Generating an i-th seed value through a computation f-function based on a time at which the i-th one-time password is generated, a time at which the one-time password was generated at the immediately preceding time, and a seed value at which the one-time password was generated; And
And generating the i-th disposable password from the i-th seed value and the response value,
Wherein the operation f function is a monotone function having a property of monotone increase or monotone decrease. The method of claim 3,
And after the generation of the i < th > seed value, deleting the time at which the immediately preceding seed value and the immediately preceding one time password are generated, and storing the i < th > seed value and time. How to create a password.

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