Data encryption and decryption method and apparatus

A data encryption apparatus comprising:

• a packet module for packeting plaintext data to be encrypted;
• a true random number generation module for generating true random numbers with a predetermined length and a random seed with a predetermined length consisting of the true random number;
• an encryption algorithm building module for building and storing encryption algorithm set;
• an assignment module for assigning an index to each encryption algorithm in encryption algorithm set built by the encryption algorithm building module;
• an encryption algorithm index random string generation module for acquiring data from the random seed generated by the true random number generation module, to generate an encryption algorithm index random string;
• a synchronous traversal module for traversing synchronously the encryption algorithm index random string generated by encryption algorithm index random string generation module and the plaintext;
• an algorithm selecting module for selecting an encryption algorithm from the encryption algorithm set according to the encryption algorithm index when traversing the encryption algorithm index random string;
• an encryption algorithm assignment module for assigning the encryption algorithm to each group of the plaintext data packeted by the packet module at the corresponding position;
• and
• an encryption processing module for encrypting the data in the plaintext by use of the encryption algorithm assigned by the encryption algorithm random assignment module, and arranging the encrypted data according to its corresponding position in the plaintext data to form a ciphertext;
• wherein the encryption algorithm index random string generation module comprises:
• a data acquisition unit for acquiring the data from the random seed generated by the true random number generation module, and returning the results of data acquisition;
• an index random string generation unit for generating and saving an encryption algorithm index random string according to the results of data acquisition returned by the data acquisition unit;
• a message digest value generation module for generating a message digest value of the encryption algorithm index random string generated by the index random string generation unit through message digest operation;
• a storage module for storing message digest values of the encryption algorithm index random strings generated by the message digest value generation module;
• and
• a comparison module for comparing the message digest value generated by the message digest value generation module with the message digest values previously stored by the storage module, and returning the comparison result to the encryption algorithm index random string generation module.

A data encryption method carried out in at least one computer, comprising:

• comprising:
• packeting plaintext data to be encrypted;
• generating true random numbers with a predetermined length and a random seed with a predetermined length formed by the true random numbers;
• establishing an encryption algorithm set and assigning an index to each encryption algorithm in the encryption algorithm set;
• acquiring data from the random seed to generate an encryption algorithm index random string;
• traversing synchronously the encryption algorithm index random string and the plaintext to be encrypted;
• selecting an encryption algorithm from the encryption algorithm set according to the encryption algorithm index when traversing the encryption algorithm index random string and assigning the encryption algorithm to each group of the plaintext data at the corresponding position;
• encrypting each group of the plaintext data with the assigned encryption algorithm respectively;
• and
• arranging the encrypted data according to its corresponding position in the plaintext data to form a ciphertext;
• wherein the encryption algorithm set comprises the encryption algorithm of all conversion routes converting from any bit data 0 or 1 in the plaintext to a bit data 0 or 1 at the corresponding position in the ciphertext, and correspondingly, the step of establishing comprises:
• selecting the encryption algorithm to cover maximum possible conversion routes from the plaintext to ciphertext;
• recording the possible conversion routes;
• determining whether all possible conversion routes are completely covered;
• if so, using all the selected encryption algorithms to create the encryption algorithm set;
• otherwise, selecting another encryption algorithm covering the maximum possible conversion routes of the remaining;
• recording the routes covered by the current encryption algorithm ;
• re-selecting an encryption algorithm covering the maximum possible conversion routes not covered, until the selected encryption algorithm can cover all the possible conversion routes;
• and
• using the encryption algorithm selected to create the encryption algorithm set.