Block.aes_encryptThe AES block cipher, in encryption mode. The string argument is the key; its length must be 16, 24 or 32 bytes.
transform src spos dst dpos encrypts or decrypts one block of data. The input data is read from byte array src at positions spos, ..., spos + blocksize - 1, and the output data is stored in byte array dst at positions dpos, ..., dpos + blocksize - 1.