ff3

Documentation

Overview

Package ff3 implements the FF3 format-preserving encryption algorithm/scheme

Index

• Variables
• type Cipher
  • func NewCipher(radix int, key []byte, tweak []byte) (Cipher, error)
  • func (c Cipher) Decrypt(X string) (string, error)
  • func (c Cipher) DecryptWithTweak(X string, tweak []byte) (string, error)
  • func (c Cipher) Encrypt(X string) (string, error)
  • func (c Cipher) EncryptWithTweak(X string, tweak []byte) (string, error)

Variables

var (
	// ErrStringNotInRadix is returned if input or intermediate strings cannot be parsed in the given radix
	ErrStringNotInRadix = errors.New("string is not within base/radix")

	// ErrTweakLengthInvalid is returned if the tweak length is not 8 bytes
	ErrTweakLengthInvalid = errors.New("tweak must be 8 bytes, or 64 bits")
)

Types

type Cipher

type Cipher struct {
	// contains filtered or unexported fields
}

A Cipher is an instance of the FF3 mode of format preserving encryption using a particular key, radix, and tweak

func NewCipher

func NewCipher(radix int, key []byte, tweak []byte) (Cipher, error)

NewCipher initializes a new FF3 Cipher for encryption or decryption use based on the radix, key and tweak parameters.

func (Cipher) Decrypt

func (c Cipher) Decrypt(X string) (string, error)

Decrypt decrypts the string X over the current FF3 parameters and returns the plaintext of the same length and format

func (Cipher) DecryptWithTweak

func (c Cipher) DecryptWithTweak(X string, tweak []byte) (string, error)

DecryptWithTweak is the same as Decrypt except it uses the tweak from the parameter rather than the current Cipher's tweak This allows you to re-use a single Cipher (for a given key) and simply override the tweak for each unique data input, which is a practical use-case of FPE for things like credit card numbers.

func (Cipher) Encrypt

func (c Cipher) Encrypt(X string) (string, error)

Encrypt encrypts the string X over the current FF3 parameters and returns the ciphertext of the same length and format

func (Cipher) EncryptWithTweak

func (c Cipher) EncryptWithTweak(X string, tweak []byte) (string, error)

EncryptWithTweak is the same as Encrypt except it uses the tweak from the parameter rather than the current Cipher's tweak This allows you to re-use a single Cipher (for a given key) and simply override the tweak for each unique data input, which is a practical use-case of FPE for things like credit card numbers.