31 results about "Pseudorandom permutation" patented technology

The invention discloses a cloud outsourcing privacy set comparison method and a cloud outsourcing privacy set comparison device, which relate to the field of communication technologies, and are used for solving the problems that security cannot be guaranteed, and the practicality and extendibility are not high existing in the existing outsourcing privacy set comparison protocol. The cloud outsourcing privacy set comparison method comprises the steps that: a first server receives a random number ri and a first ciphertext sent by a terminal, converts the first ciphertext into a second ciphertext and sends the second ciphertext and the random number ri to a second server; and the first server receives a second server random number r<S2> and a third ciphertext fed back by the second server, converts the third ciphertext into a fourth ciphertext and sends the fourth ciphertext and the second server random number r<S2> to the terminal, wherein the second server adopts a second server secret key K<S2> to obtain a pseudo-random permutation of a terminal set and calculates an intersection set of the pseudo-random permutation, the third ciphertext comprises the intersection set of the pseudo-random permutation of the terminal set and a pseudo-random function of the second server secret key K<S2>, and the fourth ciphertext comprises the intersection set of the pseudo-random permutation of the terminal set and a pseudo-random function of a terminal secret key Ki.

An encryption and authentication technique that achieves enhanced integrity verification through assured error-propagation using a multistage sequence of pseudorandom permutations. The present invention generates intermediate data-dependent cryptographic variables at each stage, which are systematically combined into feedback loops. The encryption technique also generates an authentication tag without any further steps that is N times longer than the block size where N is the number of pseudorandom permutations used in the encipherment of each block. The authentication tag provides a unique mapping to the plaintext for any number of plaintext blocks that is less than or equal to N. In addition to being a stand alone encryption algorithm, the disclosed technique is applicable to any mode that uses pseudorandom permutations such as, key dependent lookup tables, S-Boxes, and block ciphers such as RC5, TEA, and AES.

Generating a random permutation by arranging a sequence N numbers in a matrix, performing random arrangement operations on the rows of the matrix to generate an intermediary matrix, performing random arrangement operations on the columns of the intermediary matrix to generate a second intermediary matrix, and arranging the N numbers of the second intermediary matrix as a rearranged sequence of the N numbers.

The invention discloses an integrity verification method with an active attack resistance, wherein the integrity verification method mainly settles a problem of incapability of resisting active attacks in prior art. The integrity verification method comprises the steps of 1, uniformly blocking a file by a user, generating a main label and an auxiliary label, selecting a cryptographic Hash function, a pseudo random function and a pseudo random substitution function; 2, transmitting file sub-blocks to a cloud service provider by the user, deleting a local file, generating inquiry information by the user and transmitting the inquiry information to the cloud service provider; 3, generating proving information by the cloud service provider, and resisting the active attack by the user through the proving information and unidirectionality of the Hash function; and 4, verifying the proving information by the user through locally generating verification information, wherein the proving information is transmitted by the cloud service provider, if verification passes, determining a fact that the user data are complete, and otherwise, determining a fact that the data are damaged. The integrity verification method has advantages of reducing communication traffic and improving active attack resistance. The integrity verification method can be used for data integrity verification under a precondition that a client which is supported in cloud storage loses a data ownership.

In allusion to the problem that a modulator of a routine Turbo code stream has no encryption function, a modulation and encryption method based on key control is designed according to a random modulation-based combined channel and secure coding and decoding design method. By the method, an interleaver is associated with a modulator. Firstly, length of the interleaver is set as N; S is natural sequence of the length N; a Key is adopted to generate a random permutation d of natural numbers having the length N, wherein d=f(S,Key), and f is a random permutation function; mod-2 operation is carried out on d to generate a binary sequence b having the length N; and finally, random modulation is carried out on a reused coded bit sequence c, and a modulation sequence cm is outputted. During demodulation, a receiving end adopts the same Key and random function f with a coding end to generate the binary sequence b having the length N, and demodulation is carried out to output the correct bit sequence c.

The invention provides a method of generating arbitrary numbers given a seed, characterized by providing a challenge derived from the seed to a physical token, receiving an initial response from the physical token, combining the initial response with helper data associated with the challenge to produce a stable response, and generating the arbitrary numbers using a pseudo-random number generator using the stable response as a seed for the generator. Preferably one or more of these pseudo-random permutations are used as one or more round function(s) in a Feistel block cipher. The generated arbitrary numbers may also be used to create a cryptographic key.

The described system and method provide for an encryption and authentication technique that achieves enhanced integrity verification through assured error-propagation using a multistage sequence of pseudorandom permutations. The method generates intermediate data-dependent cryptographic variables at each stage, which are systematically combined into feedback loops. The encryption technique also generates an authentication tag with minimal post processing that is the size of the state. The size of the state is dependent on the number of pseudorandom permutations and the size of the LFSR. The authentication tag provides a unique mapping to the plaintext for any number of plaintext blocks that is less than or equal the size of the state. In addition to being a stand alone encryption algorithm, the disclosed technique is applicable to any mode that uses pseudorandom permutations such as, key dependent lookup tables, S-Boxes, and block ciphers such as RC5, TEA, and AES.

The invention provides a ciphertext file set correctness verification method. The method comprises the following steps: receiving a ciphertext file set sent by a cloud server and a corresponding authentication label; wherein the authentication label is obtained by substituting a preset private key into a specific label generation function and carrying out pseudo-random operation, pseudo-random replacement and corresponding accumulation operation; calculating a verification label corresponding to the ciphertext file set by using the ciphertext file set and a preset initial verification label; and comparing the authentication tag with the verification tag to verify the correctness of the ciphertext file set. According to the method, the authentication label is obtained by substituting the preset private key into the specific label generation function through the pseudo-random operation, the pseudo-random replacement and the corresponding accumulation operation, so that a large amount ofcalculation expenditure can be avoided, and the verification burden is reduced. The invention further provides a ciphertext file set correctness verification system and device and a computer readablestorage medium which all have the above beneficial effects.

The invention discloses a method for detecting the randomicity of a pseudorandom sequence based on random permutation, which belongs to the field of detection and mainly solves the problems of limitation and onesidedness existing in the traditional randomicity detection method. A series of random permutation processing, such as inversion or negative or random interleaving, is carried out on a sequence to be detected; statistics is carried out on an inverse sequence or a negative sequence or a random interleaving sequence obtained after the random permutation processing by a Cramer-von Mises detection method, a statistical value corresponding to the sequence is obtained, and the statistical value corresponding to the sequence is compared with a selected standard statistical value; if the statistical value is smaller than the standard statistical value, the sequence to be detected meets random properties; and contrarily, the sequence to be detected does not have the random properties. The invention enables the randomicity detection of the pseudorandom sequence to be more comprehensive in a detection result and can be applied to the fields of secret communication, aerospace, distance measurement, cryptography and automatic control.

The present invention provides a particle-based data security protection method, comprising: step S1: obtaining a group of plaintext data; step S2: preprocessing the plaintext data to obtain plaintext group data; step S3: performing the first forgery on the plaintext group data Obtaining permutation data by random permutation; step S4: performing block encryption on the permutation data to obtain block encryption data; step S5: performing second pseudo-random permutation on block encryption data to obtain ciphertext data. The particle-based data security protection method of the present invention reduces the probability of secret stealers stealing and restoring valid information, and improves the security of data transmission.

The invention discloses a cloud outsourcing privacy set comparison method and a cloud outsourcing privacy set comparison device, which relate to the field of communication technologies, and are used for solving the problems that security cannot be guaranteed, and the practicality and extendibility are not high existing in the existing outsourcing privacy set comparison protocol. The cloud outsourcing privacy set comparison method comprises the steps that: a first server receives a random number ri and a first ciphertext sent by a terminal, converts the first ciphertext into a second ciphertext and sends the second ciphertext and the random number ri to a second server; and the first server receives a second server random number r<S2> and a third ciphertext fed back by the second server, converts the third ciphertext into a fourth ciphertext and sends the fourth ciphertext and the second server random number r<S2> to the terminal, wherein the second server adopts a second server secret key K<S2> to obtain a pseudo-random permutation of a terminal set and calculates an intersection set of the pseudo-random permutation, the third ciphertext comprises the intersection set of the pseudo-random permutation of the terminal set and a pseudo-random function of the second server secret key K<S2>, and the fourth ciphertext comprises the intersection set of the pseudo-random permutation of the terminal set and a pseudo-random function of a terminal secret key Ki.

A system and method for pseudorandom permutation for interleaving in wireless communication is disclosed. In one embodiment, the method comprises receiving a first ordered sequence of communication symbols having a first order, permuting the first ordered sequence of communication symbols to generate a second ordered sequence of communication symbols having a second order, and outputting the second ordered sequence of communication symbols, wherein the second order is based, at least in part, on a third order having a greater size than the second order, the third order being a pseudorandom permutation defined by the input-output relationship Y = mod ⁡ ( m * S * ( S + 1 ) 2 , P ) , wherein P is the smallest power of two not less than the number of elements in the first ordered sequence, S is an input order represented by a sequence of consecutive integers from zero to P−1 in increasing order, Y is an output order represented as a sequence of integers, and m is an integer.

A method comprising the steps of creating a random permutation of data from a data input by executing at least one of a Pseudo-Random Permutation (PRP) and a Pseudo-Random Function (PRF), creating a first data block by combining the random permutation of data with a received second data block and executing an epsilon-differentially uniform function on the result of the combination, XORing the result of the epsilon-DU function evaluation with a secret key, and reducing the first data block to a first message authentication code.

The invention relates to a sequence cipher based search encryption method in a cloud storage environment. The sequence cipher based search encryption method in the cloud storage environment comprises the steps of realizing data security search by improving a key stream generation mode in sequence cipher encryption, and carrying out ECB encryption for a searched keyword to form a direct ciphertext; generating a random number by a pseudorandom generator, and generating a key stream by using the random number and the direct ciphertext through a pseudorandom replacement function; and finally carrying out XOR operation for the key stream and the direct ciphertext to obtain a concealed ciphertext, storing the concealed ciphertext at a server and accordingly building a query matching table; when a new search query occurs, firstly calculating a replacement key and then comparing data in the query matching table with the equality relationship among the concealed ciphertext of the current query session, and accordingly confirming the returned query result. The sequence cipher based search encryption method in the cloud storage environment can realize efficient data search of users, can increase the verification efficiency and can guarantee privacy security.

A method for verifying the correctness of a ciphertext file set provided by this application includes: receiving the ciphertext file set and the corresponding authentication label sent by the cloud server; wherein, the authentication label is to substitute a preset private key into a specific label generation function, Obtained by pseudo-random operation, pseudo-random permutation and corresponding accumulation operation; use the ciphertext file set and the preset initial verification label to calculate the verification label corresponding to the ciphertext file set; compare the authentication label and the verification label to verify the ciphertext file The correctness of the collection. In this method, the authentication label is obtained by substituting the preset private key into a specific label generation function through pseudo-random operation, pseudo-random permutation and corresponding accumulation operation, which can avoid a large amount of calculation overhead and reduce the verification burden. The present application also provides a system, device and computer-readable storage medium for verifying the correctness of a set of ciphertext files, all of which have the above beneficial effects.