xtea

Documentation

Overview

Package xtea implements XTEA encryption, as defined in Needham and Wheeler's 1997 technical report, "Tea extensions."

XTEA is a legacy cipher and its short block size makes it vulnerable to birthday bound attacks (see https://sweet32.info). It should only be used where compatibility with legacy systems, not security, is the goal.

Deprecated: any new system should use AES (from crypto/aes, if necessary in an AEAD mode like crypto/cipher.NewGCM) or XChaCha20-Poly1305 (from github.com/dagood/x/crypto/chacha20poly1305).

Index

• Constants
• type Cipher
  • func NewCipher(key []byte) (*Cipher, error)
  • func (c *Cipher) BlockSize() int
  • func (c *Cipher) Decrypt(dst, src []byte)
  • func (c *Cipher) Encrypt(dst, src []byte)
• type KeySizeError
  • func (k KeySizeError) Error() string

Constants

const BlockSize = 8

The XTEA block size in bytes.

Types

type Cipher

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

A Cipher is an instance of an XTEA cipher using a particular key.

func NewCipher

func NewCipher(key []byte) (*Cipher, error)

NewCipher creates and returns a new Cipher. The key argument should be the XTEA key. XTEA only supports 128 bit (16 byte) keys.

func (*Cipher) BlockSize

func (c *Cipher) BlockSize() int

BlockSize returns the XTEA block size, 8 bytes. It is necessary to satisfy the Block interface in the package "crypto/cipher".

func (*Cipher) Decrypt

func (c *Cipher) Decrypt(dst, src []byte)

Decrypt decrypts the 8 byte buffer src using the key and stores the result in dst.

func (*Cipher) Encrypt

func (c *Cipher) Encrypt(dst, src []byte)

Encrypt encrypts the 8 byte buffer src using the key and stores the result in dst. Note that for amounts of data larger than a block, it is not safe to just call Encrypt on successive blocks; instead, use an encryption mode like CBC (see crypto/cipher/cbc.go).

type KeySizeError

type KeySizeError int

func (KeySizeError) Error

func (k KeySizeError) Error() string