JP5314240B2 - Communication system - Google Patents

Description

The present invention relates to a communication channel system for establishing a communication session by a three-way handshake , and more particularly to a communication channel system for implementing encoded communication for automatically updating a shared random number .

  In general, in an authentication system, secrets are shared in advance, and mutual authentication is performed between secret sharers by sharing the pre-shared secrets.

  However, in the conventional authentication system, it is difficult to frequently update secrets to be shared due to the cost of sharing secrets.

  For this reason, conventionally, (1) the shared secret is maintained at a higher cost, and as a result (2) in the unlikely event that the secret is leaked and used illegally, the unauthorized user It was extremely difficult to see through.

  In this respect, the leakage of secrets is due to the fact that people are not gods.

  In other words, there is a problem in the mechanism for operating the cipher before the mathematical strength of the cipher, and it is caused by human intervention.

  For example, if a modern encryption key is leaked, it is probably caused by human intervention, and similarly, leaking of ID information such as a card number or credit number also involves human factors.

  This type of information leakage cannot be recognized by either the system or the user, and will wait for the damage based on the information leakage to be closed up.

In other words, including the case involving storage of ID information, secret sharing for authentication is always
1) Keep that value constant,
2) This can only be accomplished with the maintenance of keeping the value secret.

However, maintenance of this shared random number (secret) is, as yet have been committed to the norms of the people, it is a hotbed of information leakage.

As a technique for mitigating the dependency on human norms in maintenance, Chap (CHAP: see non-patent literature), which is a 1: 1 authenticator of Challenge & Response method, is known.
CHAP (PPP Challenge Handshake Authentication Protocol) Network Working Group: W. SimpsonRequest for Comments: 1994 DayDreamerObsoletes: 1334 in August 1996Category: Standards Track

According to Non-Patent Document 1, PPP ( Point-to-Point Protocol ) provides a standard method for transporting multi-protocol datagrams over point-to-point links. PPP also defines an extensible link control protocol, which allows an authentication protocol to negotiate its peers before allowing network layer protocols to transmit over the link. This document specifies a method of authentication using PPP, which makes a random challenge, using a secret key and a cryptographic hash response that depends on the challenge. RFC 1994, PPP Chap: This authentication scheme relies on a “secret” known only to the authenticator and its peers, and this secret is not transmitted over the link .

However, this Chap is the maintenance of the secret (shared random number) of the 1) and 2), which performs a human, as is evident from the description below, and remaining artificial elements, fire safety There is.

  The present application is a 1: 1 authenticator entrusted to God, so that the secret maintenance of 1) and 2) can be safely transferred from a person to a communication system in terms of practical use. Searching for authentication system technology with

  Then, consider an information technology that securely updates secret sharing for each communication session.

  According to this technology, a new secret share is established at the end of communication, and the secret share used at the start of communication can be made disposable. That is, even if secret sharing becomes a past event, and that secret leaks, it becomes a past secret.

  In this regard, if the past secrets and the current secrets are informatically independent, information leakage is no longer afraid.

  Then, it is possible to configure a system that authenticates only authorized users.

  The present invention has been made in view of the above points.

In the present invention, the 1: 1 authenticator is:
A system element that encrypts and decrypts random numbers using natural random numbers, or input / output information thereof (for example, ciphertext);
A system element that inputs a random number ciphertext into a hash function or its input / output information;
A system element or its input / output information (for example, an identifier and a verifier) as a communication part that transmits and receives a pair of a random number ciphertext and a hash function value.

  For the sake of clarity, the following symbols are used in this specification.

   [X]: Natural random number generator.

   [Y]: Random number source (natural random number or pseudo random number).

   [Z]: Natural random number generator.

Y _n : A random variable with a fixed number of digits.

Where n is the index, n = 1,2, ……, n
[X _n ]: A block of natural random numbers with a fixed number of digits.

[Y _n ]: A block of random numbers with a certain number of digits.

[Z _n ]: A block of natural random numbers with a fixed number of digits.

| [X _n ] |: The number of digits in the natural random number block.

   H (): A function for obtaining Shannon entropy of variables in ().

   h (): A function for obtaining a hash value of a variable in ().

   +: Exclusive OR.

The communication path system of the present invention is
A communication line;
And end late A and terminal B connected to the communication line,
The terminal A
As an initial value, it has three mutually independent integers [XAn], [YAn], [ZAn] ,
A first random number source (X) that generates a natural random number [XAn + 1] having the same digit as the initial value [XAn];
A second random number generator (Z) for generating a natural random number “ZAn + 1” having the same digit as the initial value [ZAn] ,

The terminal B
As initial values, [XBn] having the same value as the initial value [XAn], [YBn] having the same value as the initial value [YAn], and [ZBn] having the same value as the initial value [ZAn] are mutually independent. Has three integers,
A third random number generator (Y) that generates only a random number [YBn + 1] of the same digit as the initial value [YBn] ,

Wherein via the communication line terminal A and the terminal B is a communication path system to establish a communication in three packets of three-way handshake,
When establishing communication between the terminal A and the terminal B,
The terminal A
The natural random number [XAn + 1] is encrypted using the initial value [XAn] as an encryption key, and the information including the first ciphertext {[XAn] + [XAn + 1] is used as a first packet for the communication line. And the natural random number [XAn + 1] is encrypted using the initial value [ZAn] as an encryption key, and information including this third ciphertext {[ZAn] + [ZAn + 1]} 3 to the terminal B via the communication line,
Receiving a second packet from terminal B;

Receiving the third packet;
The gist of this is to share the values of the random number [XAn + 1], the random number [YBn + 1] derived from the natural random number, and the random number [ZAn + 1] derived from the natural random number by exchanging three packets depending on the three types of packets. .

  The present invention solves the problem of updating while ensuring secret sharing between two parties and the safety of a user ID. In other words, it is a technology for safely transferring secret sharing maintenance between two parties from a human hand to a system.

  The utility is in the following points.

(1) Invalidate leaked ID information.
(2) Make information leakage from people difficult.

  In the following description, an authentication system including an authenticator is often simply expressed as an authenticator system or simply an authenticator.

With regard to the present invention, in a normal encryption mechanism, the key and plaintext belong to different probability events, but the 1: 1 authenticator is output from the same random number source. It is configured on “Decryption Mechanism”.

  That is, a random number delivery method that reflects the independence of the natural random number block in the relationship between the key and plain text. This is the basis for constructing a 1: 1 authenticator.

Two random blocks [X _n ] shown in equation (1-1) obtained from the source [X] in an environment with one or both of the two parties (peers) across the communication path having the random number source [X] ] And [X _{n + 1} ] have the same number of digits
| [X ₁ ] | = | [X _{n + 1} ] | --------- (1-1)
Index n = 1,2, ……, n
(1-1) Pair is independent of (1-2)
H ([[X _{n + 1} ]) = H ([X _{n + 1} ] | [X _n ]) --------- (1-2)
H (): When satisfying the function to calculate Shannon entropy, or when the pair of (1-1) satisfies the predictive difficulty instead of (1-2), (1-3) (1-4) As shown in the equation, the random number [X _n ] output from the generation source [X] is used as the key K in the order indicated by the index n, and the random number [X _{n + 1} ] output after that is used in the plaintext.

That is,
Key K = [X _n ] ---------- (1-3)
Plain text = [X _{n + 1} ] --------- (1-4)
As a result, the independence of the random number block (1-2) is reflected in the essential requirements for encryption and decryption, while the person sets the initial value [X ₁ ] in advance for the two parties across the communication path. It is a “mechanism of encryption and decryption of random numbers using natural random numbers” (see FIG. 1), in which secret sharing is performed and the two parties are in a specific 1: 1 relationship.

The essential requirement for encryption and decryption of the present invention is that the key and plaintext are selected independently. The system that satisfies this requirement every time random numbers are delivered is the "random number encryption and decryption mechanism using natural random numbers". There are two algorithmic points for this mechanism: First, after a randomly chosen initial value [X ₁ ] performs the function of a key, a random number block with n = 2 instead of [X ₁ ] [ X ₂ ] is the key. Second, after the key [X ₂ ] is set, a new plaintext random block [X ₃ ] is given from the random number source [X]. As a result, the key and plaintext independence (1 -2) It is two points of always maintaining the formula.

As a result of the above mechanism, the following safety is achieved for each random number delivery:
First, the independence of equation (1-2)
H ([[X _{n + 1} ]) = H ([X _{n + 1} ] | [X _n ]) --------- (1-2)
From the request that encryption and decryption become a 1: 1 mapping, the following equation (1-5) is derived:
H (C _{n + 1} )-H ([X _{n + 1} ]) = H (K)-H (K | C _{n + 1} ) --------- (1-5)
Here, the ciphertext C _{n + 1} is a random number determined as follows:
H (C _{n + 1} | [X _n ], [X _{n + 1} ]) = 0 --------- (1-6)
Therefore, the ciphertext C _{n + 1} is also a random number.
H (C _{n + 1} )-H (X _{n + 1} ) = 0 --------- (1-7)
At the same time, derive equation (1-8):
H (K)-H (K | C _{n + 1} ) = 0 --------- (1-8)
Equation (1-8) indicates that the information on the key K is not leaked from the ciphertext block C _{n + 1} .

As a result of the execution of equations (1-1) to (1-8), the total sum of ciphertexts flowing through the communication path is always
H ([X ₁ ] + H ([X _n ]) --------- (1-9)
It can be easily calculated to have only entropy.

The expression (1-9) means that the random number block [X _n ] is safely delivered by the “random number encryption and decryption mechanism” according to the present invention, and the entropy of the initial value [X ₁ ] is It is always maintained.

That is, the entropy of encryption depends on the initial value [X ₁ ], but the sequence of the random number block [X _n ] is not derived from the initial value [X ₁ ].

In the present invention, a 1: 1 relationship having two initial values is defined based on the above 1: 1 relationship.

That is, the two parties separated spatially across the communication path are characterized in that the initial value [X ₁ ] and the initial value [Y ₁ ] are secretly shared in advance, and the two are specified 1: Stipulated in 1 relationship.

The initial value is different from the role of [X _1] and the initial value [Y _1], the initial value [X _1] as the initial value from [Y _1] also independent of each other, the invention Figure 1 and Figure below according to claim 2 The two-to-one 1: 1 relationship is superimposed.

  Of the two parties A and B at both ends of the communication path, one A has a random number source [X] considered to satisfy the equation (1-2), and the other B also satisfies the equation (2-1). Each random number block satisfies the independence of the expression (1-2) of the invention according to claim 1 and the following expression (2-1), or While satisfying the difficulty of prediction, the following expression is satisfied.

H ([[X _{n + 1} ]) = H ([X _{n + 1} ] | [X _n ]) --------- (1-2)
H ([[Y _{n + 1} ]] = H ([Y _{n + 1} ] | [Y _n ]) --------- (2-1)
This corresponds to “a mechanism for encryption and decryption of random numbers using natural random numbers”, in which both A and B share [X ₁ ] and [Y ₁ ], which are randomly selected in advance, as initial values.

Further, in the present invention, a 1: 1 authenticator is constituted by the random number blocks of the random number generation sources [X] and [Y] and the hash function, and the 1: 1 relationship defined as described above. When the key of the hash function is the random number block [X _n ] or [Y _n ], the pair of the delivered random number block [X _{n + 1} ] and its hash value h ([X _{n + 1} ]) is 1 1 authenticator, or a pair of [Y _{n + 1} ] and its hash value h ([Y _{n + 1} ]) to be delivered is an authenticator system having a 1: 1 authenticator.

This 1: 1 authenticator differs from the challenge and response method in the following points.
The Response for Request for Comments 1994 depends on the secret key and Challenge. Challenge and Response are not independent.

  There is also a type that performs secret sharing with two initial values, but Challenge and Response are not independent.

  On the other hand, in the 1: 1 authenticator of the present invention, there are two kinds of authenticators, “going and returning”, corresponding to Challenge and Response. Hereinafter, the outbound is often referred to as an identifier, and the return is referred to as an authenticator. The identifier and checker are independent of each other.

Further, the present invention relates, the authentication system may also automatically updates the secret shared by the exchange of certified Akashiko as described above.

  In other words, conventionally, the secret sharing update has been relied on the human system, but this is unnecessary.

By exchanging the authenticator of the present invention, the secret sharing starting with the initial values [X ₁ ] and [Y ₁ ] is updated for each communication session.

That is, it is updated on a per session basis via the identifier and verifier as follows:
[X ₁ ] ---> [X ₂ ] ---> [X ₃ ] --->… ---> [X _n ]
[Y ₁ ] ---> [Y ₂ ] ---> [Y ₃ ] --->… ---> [Y _n ]
This safety is based on the invention according to claim 1.

That is, the entropy of encryption seen by an eavesdropper depends on an initial value selected at random, but the random number block group [X _n ] is not a value derived from the initial value [X ₁ ]. The identifier and the checker are independent from each other.

  In this way, since new secret sharing is established at the end of communication, secret sharing at the start of communication becomes a past secret, and even if a secret leaks, it becomes a past secret from that point.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

Previously not a, with reference to FIGS. 1 and 4, an embodiment of the present invention.

FIG. 1 is a block diagram showing a mechanism for encryption and decryption of random numbers using natural random numbers [X _n ] of the authentication system according to the embodiment of the present invention, and FIG. 4 shows authentication of the authentication system according to the embodiment of the present invention. It is a time chart which shows the three way operation | movement in the continuous transaction of a child.

FIG. 1 shows the relationship with three random variables: key, plaintext, and ciphertext. A random number source [X] is in terminal A, and a random number block is sent from A to B. In this mechanism, the initial value [X ₁ ] is a randomly selected probability event, and this [X ₁ ] is replaced with a random number block [X ₂ ] of n = 2 after encryption / decryption. Then, after the key [X _n ] is always set, the plaintext random number block [X _{n + 1} ] is given from the random number source [X], and as a result, the expression (1-2) for the independence of the key and the plaintext Is established. Note that encryption and decryption keys and plaintext are independently selected. This requirement is always achieved by using natural random numbers.

(1) Mechanism of encryption and decryption of random numbers using natural random numbers The output of the natural random number source [X] is aligned to a certain number of digits to obtain a random number block [X _n ]:
| [X ₁ ] | = | [X _{n + 1} ] | --------- (1-1)
Index n = 1,2, ……, n
When any random number block satisfies the following independent expression (1-2),
H ([[X _{n + 1} ]) = H ([X _{n + 1} ] | [X _n ]) --------- (1-2)
As shown in equations (1-3) and (1-4), the random number block [X _n ] output by [X] in the order of index n is used as the key K, and the random number block [X _n ] following [X _n ] _By using ₊₁ ] in plaintext, the key K = [X _n ] ---------- (1-3)
Plain text = [X _{n + 1} ] --------- (1-4)
Automatically satisfies that key and plaintext are selected independently.

On the other hand, the two parties A and B across the communication path secretly share [X ₁ ] as an initial value in advance, so that the two parties enter a 1: 1 relationship between encryption and decryption. This is the “mechanism of random number encryption and decryption using natural random numbers” shown in FIG.

(2) Proof of safety of ciphertext The safety points of this authentication system as a cryptographic system are as follows.

(1-2)
H ([[X _{n + 1} ]) = H ([X _{n + 1} ] | [X _n ]) --------- (1-2)
From the request that encryption and decryption become a 1: 1 mapping, the following equation (1-5) is derived:
H (C _{n + 1} )-H ([X _{n + 1} ]) = H (K)-H (K | C _{n + 1} ) --------- (1-5)
Here, the ciphertext C _{n + 1} is a random number determined as follows:
H (C _{n + 1} | [X _n ], [X _{n + 1} ]) = 0 --------- (1-6)
The expression (1-6) represents that the ciphertext C _{n + 1} is determined as one on the condition of natural random numbers [X _n ] and [X _{n + 1} ]. Therefore, the ciphertext C _{n + 1} is also a random number.
H (C _{n + 1} )-H (X _{n + 1} ) = 0 --------- (1-7)
At the same time, derive equation (1-8):
H (K)-H (K | C _{n + 1} ) = 0 --------- (1-8)
Equation (1-8) indicates that the information on the key K is not leaked from the ciphertext block C _{n + 1} .

Naturally, the information of the random number [X _{n + 1} ] is not leaked. Make the algorithm of (1-6) exclusive OR. In this case, the ciphertext C _{n + 1} is
C _{n + 1} = [X _n ] + [X _{n + 1} ] --------- (1-6) '
Calculated by

The characteristics implied by equation (1-8) are important because normal symmetric key cryptosystems leak key information due to the encryption of “meaningful plaintext”. However, the key information is not leaked in (1-8). The cause is
1) The key and plaintext are both natural random numbers and are independent.
2) Both keys and plaintext are random numbers (not meaningful),
Based on the above two reasons.

  The reason why key information leaks in a normal common key cryptosystem is that plaintext bears meaning. For example, it is known that there is 4.7bit / 1character for alphabet, but from 1.0bit to 1.5bit for meaningful sentences. The key information leaks from the ciphertext by the difference between 4.7 bits and 1.5 bits.

(3) Sum of ciphertexts flowing through the communication path
As a result of executing formulas (1-1) to (1-8), the sum of the ciphertexts flowing through the communication path is always calculated.
H ([X ₁ ]) + H ([X _n ]) --------- (1-9)
(1-9) represents the total entropy of ciphertext.
Since [X _1] and [X _n] are independent, [X _1] and the joint probability entropy of _{[X n] H ([X} 1], [X n]) is expressed as,
H ([X ₁ ], [X _n ]) = H ([X ₁ ]) + H ([X _n ]) --------- (1-10)
Where the key [X ₁ ] and the plaintext [X _n ] are selected independently to determine the ciphertext [C _{n + 1} ] as one,
H (C _{n + 1} | [X ₁ ], [X _n ]) = 0 --------- (1-11)
Add equation (1-11) to both sides of equation (1-10):
H ([X ₁ ]) + H ([X _n ]) = H (C _{n + 1} | [X ₁ ], [X _n ]) + H ([X ₁ ], [X _n ]) = H (C _{n + 1} , [X ₁ ], [X _n ])
--------- (1-12)
H (C _{n + 1} , [X ₁ ], [X _n ]) is the joint probability entropy of the three random variables that make up the cryptosystem. Equation (1-12) is a proof of the following:
1) With the initial value [X ₁ ]
2) Arbitrary random number [X _n ]
3) Encrypt only once
4) Indicates that an arbitrary random number [X _n ] has been delivered safely. Note that the random number block [X _n-1 ] used in the middle disappears.

Equation (1-12) holds for any [X _n ] and always maintains the entropy of the initial value [X ₁ ] as a key. In other words, the entropy of the ciphertext C _{n + 1} flowing through the channel depends on the initial value [X ₁ ], while the delivered random block [X _n ] is not derived from the initial value [X ₁ ], That's what it means. Careful attention should be paid to this relationship.

(4) Symmetry of terminals A and B with respect to random number block [X _n ]
Expressions (1-1) to (1-9) are symmetric with respect to the random number block [X _n ]. Even if [X _n ] is the random number of the random number generation source of terminal A, the next [X _{n + 1} ] is the random number of the generation source of terminal B, and (1-1) to (1-9) There is no change. Therefore, the mechanism described in Section 3.1. Includes the case where the random number generator [X] is provided at both ends.

  Further, even if the random number source [X] of the terminal A is a natural random number and the random number source [X] of the terminal B is a pseudo-random number source, there is no change from (1-1) to (1-9). However, in this case, equation (1-2) replaces the safety of the concept of difficulty of prediction.

In the following, with reference to FIGS. 2-4, further describes embodiments of the present invention.

FIG. 2 is a block diagram showing a mechanism of random number encryption and decryption using random numbers [Y _n ] of the authentication system according to the embodiment of the present invention, and FIG. 3 is a natural random number of the authentication system according to the embodiment of the present invention. [Z _n] block diagram showing an encryption and decryption mechanisms of the random number by, FIG. 4 is a time chart showing a three-way operation in successive transactions authenticator of the authentication system according to an embodiment of the present invention.

Embodiments described in FIG. 4, the above-described first: to assume 1 authenticator.

First , a 1: 1 relationship with two initial values is defined based on the above 1: 1 relationship. In other words, two parties that are spatially separated across the communication path share the initial value [X ₁ ] and the initial value [Y ₁ ] in advance, and define the two parties in a specific 1: 1 relationship. .

The roles of the initial values [X ₁ ] and [Y ₁ ] are different. If one is dedicated to transmission, the other is an initial value dedicated to reception. Since the initial values [X ₁ ] and [Y ₁ ] are also independent of each other, this embodiment is in a state where the 1: 1 relationship of FIGS. 1 and 2 is superimposed.

In addition , a 1: 1 authenticator is defined by a pair of the hash function h and the random number block described above .

In this embodiment , the secret sharing is automatically updated by exchanging the authenticator configured as described above . In other words, conventionally, the update of secret sharing has been dependent on the human system, but it is unnecessary.

(1) 1: 1 authenticator system
The invention according to the above embodiments constitutes a 1: 1 authenticator system. A conventional technique corresponding to this is CHAP (Request for Comments 1994).

This 1: 1 authenticator system is replaced with CHAP or a conventional ID number, password, etc. to prevent damage caused by information leakage.

(2) storing an initial value [X _1] and the [Y _1] to the portable media.

The initial values [X ₁ ] and [Y ₁ ] are secrets that link the host and user into a specific 1: 1 relationship.

Thereafter, communication is an initial value between the host and user [X _1] starting from 1: 1 encryption and decryption, 1 starts the initial value [Y _1]: 1 becomes superposition of the encryption and decrypt (Figure 1 Overlay with Figure 2.)

(3) Exchange of 1: 1 authenticator As shown in FIG. 4, the random number block [X _n ] flows from the host to the user, and [Y _n ] flows from the user to the host .

The delivered random number block [X _{n + 1} ] and its hash value h ([X _{n + 1} ]) pair to the “random card mobile media” initial value [X ₁ ] = 512 bits, initial value [Y ₁ ] = Save as 512 bits and update it.

(4) Identifier and confirmor The portion corresponding to the identifier and the key in the confirmor changes for each session as follows:
From host to user: [X ₁ ] ---> [X ₂ ] ---> [X ₃ ] --->… ---> [X _n ]: ---> Identifier sequence user to host : [Y ₁ ] ---> [Y ₂ ] ---> [Y ₃ ] --->… ---> [Y _n ]: ---> Random numbers to be delivered in sequence diagram 4 of the checker when the block is [X _2], and the random number [X _1] in the key, the random number ciphertext _{[X 2] [X 1]} + [X 2] is made by the terminal a. This ciphertext [X ₁ ] + [X ₂ ] becomes the input of the hash function. A pair of the ciphertext [X ₁ ] + [X ₂ ] and the hash value h ([X ₁ ] + [X ₂ ]) is an identifier.

  In terminal B, after decrypting the ciphertext, the same encryption procedure as in terminal A is executed again to generate a hash value.

  Then, the hash value at terminal A is compared with the hash value at terminal B.

Being equal both hash value, based on the collision resistance of the hash function, the key [X _1] with the terminal A, the key [X _1] with the terminal B, but is determined to be equal in overwhelming probability .

(5) 1: 1 authenticator function The identifier and verifier performed the following functions:
Secret sharing between two parties (key)
User ID
The password and password functions are collectively referred to as “1: 1 authenticator using natural random numbers”.

(6) Initial values [X ₁ ] and [Y ₁ ] need not be saved The two parties across the communication path are given a specific 1: 1 relationship by being given initial values [X ₁ ] and [Y ₁ ]. However, it is not necessary to continuously store the initial value for re-authentication. The initial values [X ₁ ] and [Y ₁ ] change to random numbers [X ₂ ] and [Y ₂ ], and once entered into the authenticator system, the initial values [X ₁ ] and [Y ₁ ] are referenced again. Because it is never done.

At this time, the random numbers [X ₁ ] and [X ₂ ] and the random numbers [Y ₁ ] and [Y ₂ ] are independent of each other. Therefore, even if the initial values [X ₁ ] and [Y ₁ ] leak from the authenticator system, after the random numbers [X ₁ ] and [Y ₁ ] change to the random numbers [X ₂ ] and [Y ₂ ], It will be a past incident. The leaked [X ₁ ] and [Y ₁ ] are already invalid.

(7) shared secret initial value [X _1] as the initial value [Y _1] updated initial value for each communication session of [X _1] as the initial value [Y _1] is taken over by the natural random number [X _n] .

[X ₁ ] ---> [X ₂ ] ---> [X ₃ ]… ---> [X n ]
[Y ₁ ] ---> [Y ₂ ] ---> [Y ₃ ]… ---> [Y _n ]
As described above, the safety when the maintenance is performed on a session basis is based on the following procedure . In other words, 1) the entropy of encryption seen by an eavesdropper depends on the randomly chosen initial value, but 2) the random block group [X _n ] is not a random value derived from the initial value [X ₁ ], and 3) The identifier and the verifier are independent of each other. 4) The past secret [X ₁ ] and [Y ₁ ] and the current secret [X _n ] and [Y _n ] are cryptographically independent of each other. It is. Therefore, information leakage is no longer afraid.

(8) Largest feature In this regard, it has been impossible to prevent information leakage from the human system with the conventional security technology. Even if the encryption strength is increased, information leakage from human systems cannot be prevented. This is due to the cryptographic mechanism. However, the authenticator system using natural random numbers according to the present invention updates the authentication secret as needed based on the security of the natural random numbers every time the communication session is terminated. Secrets are automatically updated from time to time, without human intervention. Since the past secret and the current secret are independent, information leakage is no longer afraid, the leaked information becomes invalid. Therefore, the authenticator system is a system that prevents damage even if the password is leaked Make it possible to build

Disabling information leaks from the human system is not within the concept of security. Security is established at the expense of convenience, the identifier of the natural random number, and vice versa, but rather, is an IT So for survive Reno convenience.

  The present invention can be used for an authentication system including a 1: 1 authenticator.

FIG. 1 is a block diagram illustrating a mechanism for encryption and decryption of a random number using a natural random number [X _n ] in the authentication system according to the embodiment of the present invention. FIG. 2 is a block diagram showing a mechanism of random number encryption and decryption using a random number [Y _n ] of the authentication system according to the embodiment of the present invention. FIG. 3 is a block diagram showing a random number encryption / decryption mechanism using a natural random number [Z _n ] in the authentication system according to the embodiment of the present invention. FIG. 4 is a time chart showing a three-way operation in a continuous transaction of the authenticator of the authentication system according to the embodiment of the present invention.

Explanation of symbols

[X]: Natural random number source
[Y]: Random number source
[Z]: Natural random number source
Y _n : random variable
n: Index
[X _n ]: Natural random number block
[Y _n ]: Random number block
[Z _n ]: Natural random number block
| [X _n ] |: Number of digits in natural random number block
H (): A function that calculates the Shannon entropy of the variable in ()
h (): A function that calculates the hash value of the variable in ()
+: Exclusive OR

Claims (2)

A communication line;
And end late A and terminal B connected to the communication line,
The terminal A
As an initial value, it has three mutually independent integers [XAn], [YAn], [ZAn],
A first random number source (X) that generates a natural random number [XAn + 1] having the same digit as the initial value [XAn];
A second random number generator (Z) for generating a natural random number “ZAn + 1” having the same digit as the initial value [ZAn],
The terminal B
As initial values, [XBn] having the same value as the initial value [XAn], [YBn] having the same value as the initial value [YAn], and [ZBn] having the same value as the initial value [ZAn] are mutually independent. Has three integers,
A third random number generator (Y) that generates only a random number [YBn + 1] of the same digit as the initial value [YBn],
A communication path system in which the terminal A and the terminal B establish communication with three types of packets of three-way handshake via the communication line,
When establishing communication between the terminal A and the terminal B,
The terminal A
The natural random number [XAn + 1] is encrypted using the initial value [XAn] as an encryption key, and the information including the first ciphertext {[XAn] + [XAn + 1] is used as a first packet for the communication line. And the natural random number [XAn + 1] is encrypted using the initial value [ZAn] as an encryption key, and information including this third ciphertext {[ZAn] + [ZAn + 1]} 3 to the terminal B via the communication line,
Receiving a second packet from terminal B;
The terminal B
When the first packet is received, information including the second ciphertext {[YBn] + [YBn + 1]} obtained by encrypting the random number [YBn + 1] with the initial value [YBn] is converted into the second packet. To the terminal A,
Receiving the third packet;
In this way, by exchanging three packets based on the three types of packets, the random number [XAn + 1], the random number [YBn + 1], and the random number [ZAn + 1] derived from the natural random number are shared. Communication channel system. The communication path system according to claim 1, wherein the value shared by the terminal A and the terminal B is set as a next initial value .

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