CN102811122A - Single-key public cryptosystem - Google Patents

Abstract

The invention relates to a single-key public cryptosystem. In the cryptosystem, a sender selects a serial number k first, then, extracts a scrambling key with the same length with a plaintext sequence m=m1, m2..., ms from R=(rk|k = 1, 2,..., n; n<infinity) for encryption operation to obtain a ciphertext c=msort(r), at last, sends k and c from a public channel to a receiver. According to the serial number k, the receiver extracts a scrambling key from R= (rk|k = 1, 2,..., n; n<infinity) for decryption operation to obtain a plaintext m=csort (sort(r)). The cryptosystem solves the problem of a large amount of key generation, storage and distribution in the traditional single-key system. Compared with the traditional single-key cryptosystem, the single-key public cryptosystem provided by the invention has a key that can be public, and compared with the traditional dual-key public cryptosystem, the single-key public cryptosystem provided by the invention has an encryption key and a decryption key which are the same to each other, thereby integrating the characteristics of the two cryptosystems. The single-key public cryptosystem has the largest advantage of easiness in realizing the 'once a crypto' encryption which cannot be decrypted in theory. The single-key public cryptosystem provided by the invention can be widely applied in various confidential departments and political, economical, cultural and social fields (such as e-government, e-commerce and other relevant fields) for serving the development of national economy, thereby having a broad application prospect in the market.

Description

Single key open code system

Technical field

The present invention relates to the cryptological technique field, particularly a kind of single key open code system.

Background technology

The modern password system can be divided into conbined public or double key system and single key system two big classes.

The characteristics of conbined public or double key password are that different keys is used in encryption and decryption, and decruption key is maintained secrecy, and encryption key can openly be propagated and the not fail safe of entail dangers to cryptographic system, and the maximum shortcoming of dual key encryption algorithm is that arithmetic speed is slower; The fail safe of most of conbined public or double key system can be summed up as the three major types types such as intractability of discrete logarithm problem on intractability and the elliptic curve of discrete logarithm problem on the intractability, finite field of the plain resolution problem of big integer.Typical conbined public or double key algorithm has RSA, EIGamal and Menezes-Vanstone etc.

The characteristics of single key password are to encrypt or decipher all to use same key, and therefore, the fail safe of key is depended in the fail safe of this cryptographic system fully, if the key leakage, just then this cryptographic system would be broken.Typical single key algorithm has DES, AES and IDEA etc.

The advantage of single key password is a fast operation; But because communicating pair all uses identical key pair information (data) to carry out encryption and decryption; So in order to ensure safety; Communicating pair must use other safe lane to come distributed key, and method commonly used is to transmit key with special courier (or safe lane); Under computer network environment, people use the common signal channel of network to transmit encrypt file on the one hand, need other safe lane distributed key on the one hand again, this contradiction that just seems itself, and cost is quite expensive.

In addition; In single key system; When communicating pair transmits with single key AES information of carrying out at every turn; All need use the ignorant only key of other users, this number of keys that can make that communicating pair had becomes geometric growth, thereby brings the insoluble problems such as generation, storage and distribution of a large amount of keys.

Summary of the invention

Goal of the invention of the present invention is in order to overcome the defective that above prior art exists, a kind of novel single key open code system to be provided, compare with the single key cryptographic system of tradition, and its key can disclose; Compare with traditional conbined public or double key cryptographic system, its encrypt and decrypt key is identical, thereby has taken into account the characteristics of these two kinds of encryption systems.

In order to realize the foregoing invention purpose, the technical scheme that the present invention takes is: this list key open code system is to choose Gauss-markoff process to produce random sequence set R={r _k| k=1,2 ..., n; N＜∞ }, the permutation cipher of encrypt and decrypt algorithm use " one-time pad ".

Transmit leg is at first selected a sequence number k, then from R={r _k| k=1,2 ..., n; N＜∞ } the middle extraction and plaintext sequence m=m ₁m ₂M _sIsometric scramble key

Carry out cryptographic calculation and get ciphertext c=m _{Sort (r)}Send k and c to recipient from overt channel at last;

The recipient is according to sequence number k, from R={r _k| k=1,2 ..., n; N＜∞ } the middle scramble key that extracts

Carry out decrypt operation and get expressly m=c _{Sort (sort (r))}

Specifically according to the following steps:

(1) generation of Gauss-Markov random sequence set

Gauss-Markov random sequence can be by recurrence formula x _i=ρ x _I-1+ ω _iProduce ω in the formula _iBe a zero-mean, independence and same (white) Gaussian stochastic variable that distributes, ρ confirms x _iAnd x _I-1Between a parameter of degree of correlation, promptly

σ ²It is variance;

Optional one group of ρ, x ₀And t, can generate a Gauss-Markov random sequence x ₁x ₂X _t, make it equal r ₁In like manner can get r ₂, r ₃..., constitute Gauss-Markov random sequence set R={r thus _k| k=1,2 ..., n; N＜∞ };

(2) encrypt and decrypt algorithm

Optional a certain random sequence r _k∈ R is from r _kThe middle extraction and plaintext m=m ₁m ₂M _sIsometric one section of ∈ M

As the scramble key that plaintext m is carried out the encrypt and decrypt computing;

AES:

G be with

Subscript vector after middle element sorts from small to large, then ciphertext c=m _g∈ C, m _gElement among the expression plaintext m carries out in-place computation according to g;

Decipherment algorithm: $f=\mathrm{Sort}\left(\mathrm{Sort}\left(\stackrel{\&OverBar;}{r}\right)\right),$ M=c expressly then _f

The advantage of the single key public encryption of the present invention system:

As long as a chooses different serial numbers k, encrypt just can accomplish " one-time pad ", know that by Shannon information theory this password can not be decoded in theory;

B, k and c can send from overt channel simultaneously; Even the disabled user has intercepted and captured k and c, under the situation of not knowing scramble key , still can not recover expressly m.

Description of drawings

Fig. 1 is the schematic diagram of the single key open code of the present invention system;

Fig. 2 is the encrypt and decrypt figure as a result of original image.

Embodiment

Single key public encryption system of the present invention is made up of following five parts:

A. space M expressly: all set expressly;

B. cryptogram space C: the set of all ciphertexts;

C. key space R: the set of all keys (random sequence of the maintaining secrecy set R={r that the present invention utilizes communicating pair to own together _k| k=1,2 ..., n; N＜∞ } constitute key space);

D. AES E: by the set of the enciphering transformation of cipher controlled;

E. decipherment algorithm D: by the set of the deciphering conversion of cipher controlled.

When carrying out secure communication, transmit leg is optional k random sequence r from the set R that maintains secrecy _kAs the key of communicating pair, carry out cryptographic calculation and get ciphertext

Send k and c to recipient from overt channel together then, the recipient extracts key r according to k from R _k, carry out decrypt operation and get expressly Because the encryption and decryption computing only and r _kRelevant, irrelevant with k, so k can disclose, thereby obtain a kind of novel single key open code system, its principle is as shown in Figure 1.In the present invention, k only indicates the selected random sequence r of communicating pair _kSequence number, its encrypt and decrypt information is hidden in secret r fully _kIn, there is not direct relation with k, so k can transmit from overt channel in company with ciphertext c together; Therefore disabled user (assailant) is not if know r _kEven, intercepted and captured c and k, also be difficult to decoding and obtain expressly m.Random sequence r is depended in the fail safe of this system fully _kRandomness, complexity, be difficult to analytical and unpredictable property.

The implementation method of the single key open code of the present invention system:

Suppose that transmit leg will be that 256 * 256 the original image (shown in Fig. 2 (a)) of maintaining secrecy sends the recipient to through overt channel with a width of cloth size.

One, transmit leg is operated as follows:

Step1, optional ρ=0.2, x ₀=0.5 substitution x _i=ρ x _I-1+ ω _i, generate random sequence r ₁∈ R;

Step2, convert original image into expressly sequence m=m ₁m ₂M ₆₅₅₃₆, from r ₁The middle extraction and the isometric scramble key of plaintext sequence m

Carry out cryptographic calculation and get encrypted result c=m _{Sort (r)}(shown in Fig. 2 (b));

Setp3, send k=1 and ciphertext c to recipient through overt channel.

Two, operate as follows the side of meeting and sending off:

Step1, according to k=1, from R, extract and the isometric scramble key of ciphertext sequence c

Carry out decrypt operation and get m '=c _{Sort (sort (r))}

Step2, convert m ' into 256 * 256 picture format and get decrypted result (shown in Fig. 2 (c)).

By knowing like Fig. 2, decrypted result (c) has been reduced to original image (a).

Claims (1)

1. single key open code system, it is characterized in that: transmit leg is at first selected a sequence number k, then from R={r _k| k=1,2 ..., n; N＜∞ } the middle extraction and plaintext sequence m=m ₁m ₂M _sIsometric scramble key

Carry out cryptographic calculation and get ciphertext c=m _{Sort (r)}Send k and c to recipient from overt channel at last;

The recipient is according to sequence number k, from R={r _k| k=1,2 ..., n; N＜∞ } the middle scramble key that extracts Carry out decrypt operation and get expressly m=c _{Sort (sort (r))}

Specifically according to the following steps:

(1) generation of Gauss-Markov random sequence set

Gauss-Markov random sequence can be by recurrence formula x _i=ρ x _I-1+ ω _iProduce ω in the formula _iBe a zero-mean, independence and same (white) Gaussian stochastic variable that distributes, ρ confirms x _iAnd x _I-1Between a parameter of degree of correlation, promptly

σ ²It is variance;

Optional one group of ρ, x ₀And t, can generate a Gauss-Markov random sequence x ₁x ₂X _t, make it equal r ₁In like manner can get r ₂, r ₃..., constitute Gauss-Markov random sequence set R={r thus _k| k=1,2 ..., n; N＜∞ };

(2) encrypt and decrypt algorithm

Optional a certain random sequence r _k∈ R is from r _kThe middle extraction and plaintext m=m ₁m ₂M _sIsometric one section of ∈ M

As the scramble key that plaintext m is carried out the encrypt and decrypt computing;

AES:

G be with

Subscript vector after middle element sorts from small to large, then ciphertext c=m _g∈ C, m _gElement among the expression plaintext m carries out in-place computation according to g;

Decipherment algorithm: $f=\mathrm{Sort}\left(\mathrm{Sort}\left(\stackrel{\&OverBar;}{r}\right)\right),$ M=c expressly then _f

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