mirror of
https://gogs.blitter.com/RLabs/xs
synced 2024-08-14 10:26:42 +00:00
f5be3578a8
2/3 Added vendor/ dir to lock down dependent pkg versions.
The author of git.schwanenlied.me/yawning/{chacha20,newhope,kyber}.git has copied
their repos to gitlab.com/yawning/ but some imports of chacha20 from newhope still
inconsistently refer to git.schwanenlied.me/, breaking build.
Licenses for chacha20 also changed from CC0 to AGPL, which may or may not be an
issue. Until the two aforementioned issues are resolved, locking to last-good
versions is probably the best way forward for now.
To build with vendored deps, use make VENDOR=1 clean all
3/3 Moved body of CI push script into bacillus/
90 lines
2.8 KiB
Go
90 lines
2.8 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// 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
|
|
// golang.org/x/crypto/chacha20poly1305).
|
|
package xtea // import "golang.org/x/crypto/xtea"
|
|
|
|
// For details, see http://www.cix.co.uk/~klockstone/xtea.pdf
|
|
|
|
import "strconv"
|
|
|
|
// The XTEA block size in bytes.
|
|
const BlockSize = 8
|
|
|
|
// A Cipher is an instance of an XTEA cipher using a particular key.
|
|
type Cipher struct {
|
|
// table contains a series of precalculated values that are used each round.
|
|
table [64]uint32
|
|
}
|
|
|
|
type KeySizeError int
|
|
|
|
func (k KeySizeError) Error() string {
|
|
return "crypto/xtea: invalid key size " + strconv.Itoa(int(k))
|
|
}
|
|
|
|
// NewCipher creates and returns a new Cipher.
|
|
// The key argument should be the XTEA key.
|
|
// XTEA only supports 128 bit (16 byte) keys.
|
|
func NewCipher(key []byte) (*Cipher, error) {
|
|
k := len(key)
|
|
switch k {
|
|
default:
|
|
return nil, KeySizeError(k)
|
|
case 16:
|
|
break
|
|
}
|
|
|
|
c := new(Cipher)
|
|
initCipher(c, key)
|
|
|
|
return c, nil
|
|
}
|
|
|
|
// BlockSize returns the XTEA block size, 8 bytes.
|
|
// It is necessary to satisfy the Block interface in the
|
|
// package "crypto/cipher".
|
|
func (c *Cipher) BlockSize() int { return BlockSize }
|
|
|
|
// 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).
|
|
func (c *Cipher) Encrypt(dst, src []byte) { encryptBlock(c, dst, src) }
|
|
|
|
// Decrypt decrypts the 8 byte buffer src using the key and stores the result in dst.
|
|
func (c *Cipher) Decrypt(dst, src []byte) { decryptBlock(c, dst, src) }
|
|
|
|
// initCipher initializes the cipher context by creating a look up table
|
|
// of precalculated values that are based on the key.
|
|
func initCipher(c *Cipher, key []byte) {
|
|
// Load the key into four uint32s
|
|
var k [4]uint32
|
|
for i := 0; i < len(k); i++ {
|
|
j := i << 2 // Multiply by 4
|
|
k[i] = uint32(key[j+0])<<24 | uint32(key[j+1])<<16 | uint32(key[j+2])<<8 | uint32(key[j+3])
|
|
}
|
|
|
|
// Precalculate the table
|
|
const delta = 0x9E3779B9
|
|
var sum uint32
|
|
|
|
// Two rounds of XTEA applied per loop
|
|
for i := 0; i < numRounds; {
|
|
c.table[i] = sum + k[sum&3]
|
|
i++
|
|
sum += delta
|
|
c.table[i] = sum + k[(sum>>11)&3]
|
|
i++
|
|
}
|
|
}
|