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CryptoLib in Java

PinBlock in Java

Implementation of PinBlock Format 0 based on ISO-9564 standard. The PIN block is constructed by XOR-ing two 64-bit fields: the plain text PIN field and the account number field, both of which comprise 16 four-bit nibbles.

The plain text PIN field is :

  • one nibble with the value of 0, which identifies this as a format 0 block
  • one nibble encoding the length N of the PIN
  • N nibbles, each encoding one PIN digit
  • 14−N nibbles, each holding the Padding (cryptography)|fill value 15 (i.e. 1111 or F)

The account number field is:

  • four nibbles with the value of zero
  • 12 nibbles containing the right-most 12 digits of the primary account number(PAN), excluding the check digit

Extended PIN blocks

Formats 0 to 3 are all suitable for use with the Triple Data Encryption Algorithm, as they correspond to its 64-bit block size. However the standard allows for other encryption algorithms with larger block sizes, e.g. the Advanced Encryption Standard has a block size of 128 bits. In such cases the PIN must be encoding into an extended PIN block, the format of which is defined in a 2015 amendment to ISO 9564-1. In this library, we have used 3DES in ECB/NoPadding mode.

For better clarification please refer to the following online tool: https://neapay.com/online-tools/calculate-pin-block.html

Triple DES in Java

  • Build secret key based on an intial seed

  • Makeup secret keys to be suitable for 3DES encryption

  • Encryption / Decryption

Debug/Run/Unit-test/Benchmark

This is provided to be built/test/run on VS Code IDE easily. If you would like to build it in command line, you can use:

mvn clean package

The unit-tests will be run automatically in this way. But to run the sample PinBlockApp.java manually, you can run the following command:

cd cryptolib
java -cp target/cryptolib-0.1.0.jar cryptolib.PinBlockApp

Before running this command, please check the built cryptolib jar file version/name.

The benchmarks also can be run by the following commands:

cd benchmark
java -jar target/benchmarks.jar