Block encryption method and block decryption method having integrity verification

摘要

An encryption method and decryption method are provided. The encryption method divides an electronic file into a plurality of message blocks, wherein the message blocks have a sequence. The encryption method sets a checking vector as the last message block. The encryption method performs the following steps on each message block according to the sequence: generating an input block, deriving an output block by encrypting the input block by an encryption key, and deriving an encrypted block by applying XOR operation to the output block and the previous message block, wherein the input block is equivalent to applying XOR operation to the message block, the output block corresponding to the previous message block, and the message block before the previous one. The encryption method generates an electronic encrypted file by concatenating the encrypted blocks. The decryption method performs a series of operations corresponding to the above operations.

主权项

1. A computer-implemented block encryption method, comprising:
(a) obtaining a first vector and a second vector; (b) dividing an electronic file into a plurality of message blocks, wherein the message blocks have a sequence; (c) adding a checking vector into the message blocks as the last one of the message blocks; (d) performing the following operations on each of the message blocks according to the sequence:
(d1) generating an input block, wherein a value of the input block is equal to a value obtained by performing an XOR operation on the message block, an output block corresponding to a previous message block of the message block, and a message block before the previous message block of the message block;(d2) encrypting the input block by using a key to obtain an output block; and(d3) performing an XOR operation on the output block and the previous message block of the message block to obtain an encrypted block; and (e) concatenating the encrypted blocks according to the sequence to generate an electronic encrypted file, wherein the output block corresponding to the previous message block of the message block is the first vector and the message block before the previous message block of the message block is an all-zero vector when the step (d) processes the first one of the message blocks, wherein the message block before the previous message block of the message block is the second vector when the step (d) processes the second one of the message blocks.