string-data-encryption

代码说明：

  Data Encryption by Matrix Multiplication We will only use numbers 0 to 26 for the encryptive mathematics operation. Numbers from 1 to 26 are for letters from A to Z and 0 is for all non-letter characters. To minimize usage of numbers, all letters are converted to upper case. The original message is converted to number array according to the ASCII table and minus 64. We partition whole array into blocks of 8 numbers. The last block may be added several zeros. Then multiply each block by the an 8x8 matrix A which is invertible in Z27 to get cipher data. The decryption is the same process except to use its inverse matrix B. For good visual reading, we convert all non-letter characters to under score for the decryption.