An implementation of the NIST approved FF1, FF3 and FF3-1 Format Preserving Encryption (FPE) algorithms in Python.

This package implements the FPE algorithm for Format Preserving Encryption as described in the March 2016 NIST publication 800-38G Methods for Format-Preserving Encryption, and revised on February 28th, 2019 with a draft update for FF3-1.

• NIST Recommendation SP 800-38G (FF3)
• NIST Recommendation SP 800-38G Revision 1 (FF3-1)

To compile the example.c with the fpe library, just run

make

To build on macOS:

brew install openssl
export CFLAGS="-I$(brew --prefix openssl)/include"
export LDFLAGS="-L$(brew --prefix openssl)/lib"

Run the example in example.c.

./example EF4359D8D580AA4F7F036D6F04FC6A94 D8E7920AFA330A73 10 890121234567890000

FF1 ciphertext: 318181603547192051
FF3 ciphertext: 750918814058654607

Run the tests

There are official test vectors for both FF1 and FF3 provided by NIST. You can run test.py with python 3.x. with a known test vector:

make test

This implementation is based on OpenSSL's BIGNUM and AES, so you need to install OpenSSL first.

There are several functions for FF1 and FF3 algorithm, respectively.

1. Create and delete FF1 key and tweak

FPE_KEY* FPE_ff1_create_key(const char *key, const char *tweak, const unsigned int radix);

void FPE_ff1_delete_key(FPE_KEY *keystruct);

2. encrypt or decrypt text using FF1 algorithm

void FPE_ff1_encrypt(char *plaintext, char *ciphertext, FPE_KEY *keystruct)
void FPE_ff1_decrypt(char *ciphertext, char *plaintext, FPE_KEY *keystruct)

3. Create and delete FF3 key and tweak

FPE_KEY* FPE_ff3_create_key(const char *key, const char *tweak, const unsigned char radix);
FPE_KEY* FPE_ff3_1_create_key(const char *key, const char *tweak, const unsigned char radix);

void FPE_ff3_delete_key(FPE_KEY *keystruct);

4. encrypt or decrypt text using FF3 algorithm

void FPE_ff3_encrypt(char *plaintext, char *ciphertext, FPE_KEY *keystruct);
void FPE_ff3_decrypt(char *ciphertext, char *plaintext, FPE_KEY *keystruct);

1. Performance testing
2. Custom alphabet support