MagTek USB MagnePrint Swipe Reader with Encryption - Manual (Page 71)

63
APPENDIX C. GUIDE ON DECRYPTING DATA
When a data field consists of more than one block, Cipher Block Chaining (CBC) method is used
by the encrypting algorithm.
To decrypt this group of data, follow these steps:
• Start decryption on the last block.
• The result of the decryption is then XORed with the previous block.
• Continue until reaching the first block.
• The first block can skip the XOR operation.