FPE 0.1.1

Format Preserving Encryption with FF1 and FF3-1

Installation

This library uses PyCryptodome which means a C compiler is required. For Mac and Linux users this is already installed. For Windows users please follow this guide from PyCryptoDome.

https://pycryptodome.readthedocs.io/en/latest/src/installation.html#windows-from-sources

Usage

The libray is imported as from FPE import FPE.

To generate a tweak use FPE.generate_tweak(tweak_length) where tweak_len is the length of the tweak in bytes. Note that for FF3-1 the tweak_length must be 7 bytes.

To generate a key use FPE.generate_key(), this will generate a 16 byte key.

To make a cipher object use cipher = FPE.New(key,tweak,mode)

Currently supported modes are FPE.Mode.FF1 and FPE.Mode.FF3-1

To encrypt use cipher.encrypt(plaintext,format)

Currently supported formats are:

Format.DIGITS
Format.CREDITCARD
Format.LETTERS
Format.STRING
Format.EMAIL
Format.CPR

to decrypt use cipher.decrypt(ciphertext,format)

The library also supports CSV files

To encrypt a csv file use cipher.encryptCSV(InputFilePath,OutputFilePath,formats) where formats is a list of formats sorted by the columns

To decrypt a csv file use cipher.decryptCSV(InputFilePath,OutputFilePath,formats)

to generate a random CSV file with certain formats use cipher.generateData(OutputFilePath,rows,formats,variables) where rows define the number of rows in the CSV file. Formats is the lists of formats to use. Variables is the list of variable names used for the first row.

Examples

Example of encrypting and decrypting "12345" as DIGITS and printing the output

from FPE import FPE

if __name__ == '__main__':

	T = FPE.generate_tweak(8)
	
	key = FPE.generate_key()
	
	cipher = FPE.New(key,T,FPE.Mode.FF1)
	
	ciphertext = cipher.encrypt('12345',FPE.Format.DIGITS)
	
	print(ciphertext)
	
	plaintext = cipher.decrypt(ciphertext,FPE.Format.DIGITS)
	
	print(plaintext)

Example of generating, encrypting and decrypting a 1000 row CSV file

from FPE import FPE, Format

variables = [
	'Username','Password','Email','PhoneNumber','Cpr-number',
	'Creditcard','adress','city','zip','country'
]


formats = [
	Format.LETTERS, Format.STRING, Format.EMAIL, Format.DIGITS,
	Format.CPR, Format.CREDITCARD,Format.STRING,Format.LETTERS,
	Format.DIGITS,Format.LETTERS
]

if __name__ == '__main__':
	
	T = FPE.generate_tweak(7)
	key = FPE.generate_key()
	cipher = FPE.New(key,T,FPE.Mode.FF3)
	cipher.generateData('testData.csv',1000,formats,variables)
	cipher.encryptCSV('testData.csv','encryptedData.csv',formats)
	cipher.decryptCSV('encryptedData.csv','decryptedData.csv',formats)