Encode/Decode PIN Block card payments

Encode - Calculate PIN block

Enter the 4..11 digit PIN number

Enter the 16 or 19 digits card number:

Enter the PIN Block Padding/Filler character, 0-9 A-F::

Select the PIN Block format Format 0 (ISO-0) Format 1 (ISO-1) Format 2 (ISO-2) Format 3 (ISO-3) Format 4 (ISO-4)

Encode PIN block

Decode - Calculate clear PIN

Enter the card number PAN, Padding, and PIN block, in HEX. Decode PIN block

Encrypt Encoded PIN block

Enter the 16 digit PIN block

Enter the PIN Block Filler character, 0 or F:

Select Algorythm Triple DES DES

Encrypt PIN block

Decrypt Encoded PIN Block

Enter the Encrypted PIN Block, and the key, in HEX. Decrypt PIN block

How PIN block Encoding works

The most common scenario is ISO-0 PIN Block Encoding.

The block calculation begins with setting up the two parts, Block1 and Block2

PIN block part one is built from character "0", followed by the length of the PIN, then the PIN number, and then fill the value up to 16 characters with "F".

In our example, 0+4+1111+FFFFFFFFFF=041111FFFFFFFFFF

PIN block part two is built from four zeroes, followed by the card number, without the first 3 digits, and without the last digit. So 12 digits.

In our example, for PAN 5516422217375116, the block will be 0000 642221737511

Next step is to do a HEX XOR on the two blocks

XOR(block1, block2)

And then, finally, apply a 3DES encryption of the above block with the PIN Encryption key.

How PIN block Encryption works

In order to encrypt the PIN block, 3DES or single DES will be applied.

For single DES, 16-hex , 8 bytes key is used.

For Triple DES, a double key is used, 32 hex , 16 bytes.