diff options
author | kali kaneko (leap communications) <kali@leap.se> | 2021-11-29 01:46:27 +0100 |
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committer | kali kaneko (leap communications) <kali@leap.se> | 2021-11-29 18:14:16 +0100 |
commit | 18f52af5be3a9a0c73811706108f790d65ee9c67 (patch) | |
tree | e13cbacb47d56919caa9c44a2b45dec1497a7860 /vendor/golang.org/x/crypto/xtea | |
parent | ebcef0d57b6ecb5a40c6579f6be07182dd3033ba (diff) |
[pkg] update vendor
Diffstat (limited to 'vendor/golang.org/x/crypto/xtea')
-rw-r--r-- | vendor/golang.org/x/crypto/xtea/block.go | 66 | ||||
-rw-r--r-- | vendor/golang.org/x/crypto/xtea/cipher.go | 90 |
2 files changed, 156 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/xtea/block.go b/vendor/golang.org/x/crypto/xtea/block.go new file mode 100644 index 0000000..fcb4e4d --- /dev/null +++ b/vendor/golang.org/x/crypto/xtea/block.go @@ -0,0 +1,66 @@ +// 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. + +/* + Implementation adapted from Needham and Wheeler's paper: + http://www.cix.co.uk/~klockstone/xtea.pdf + + A precalculated look up table is used during encryption/decryption for values that are based purely on the key. +*/ + +package xtea + +// XTEA is based on 64 rounds. +const numRounds = 64 + +// blockToUint32 reads an 8 byte slice into two uint32s. +// The block is treated as big endian. +func blockToUint32(src []byte) (uint32, uint32) { + r0 := uint32(src[0])<<24 | uint32(src[1])<<16 | uint32(src[2])<<8 | uint32(src[3]) + r1 := uint32(src[4])<<24 | uint32(src[5])<<16 | uint32(src[6])<<8 | uint32(src[7]) + return r0, r1 +} + +// uint32ToBlock writes two uint32s into an 8 byte data block. +// Values are written as big endian. +func uint32ToBlock(v0, v1 uint32, dst []byte) { + dst[0] = byte(v0 >> 24) + dst[1] = byte(v0 >> 16) + dst[2] = byte(v0 >> 8) + dst[3] = byte(v0) + dst[4] = byte(v1 >> 24) + dst[5] = byte(v1 >> 16) + dst[6] = byte(v1 >> 8) + dst[7] = byte(v1 >> 0) +} + +// encryptBlock encrypts a single 8 byte block using XTEA. +func encryptBlock(c *Cipher, dst, src []byte) { + v0, v1 := blockToUint32(src) + + // Two rounds of XTEA applied per loop + for i := 0; i < numRounds; { + v0 += ((v1<<4 ^ v1>>5) + v1) ^ c.table[i] + i++ + v1 += ((v0<<4 ^ v0>>5) + v0) ^ c.table[i] + i++ + } + + uint32ToBlock(v0, v1, dst) +} + +// decryptBlock decrypts a single 8 byte block using XTEA. +func decryptBlock(c *Cipher, dst, src []byte) { + v0, v1 := blockToUint32(src) + + // Two rounds of XTEA applied per loop + for i := numRounds; i > 0; { + i-- + v1 -= ((v0<<4 ^ v0>>5) + v0) ^ c.table[i] + i-- + v0 -= ((v1<<4 ^ v1>>5) + v1) ^ c.table[i] + } + + uint32ToBlock(v0, v1, dst) +} diff --git a/vendor/golang.org/x/crypto/xtea/cipher.go b/vendor/golang.org/x/crypto/xtea/cipher.go new file mode 100644 index 0000000..a4c2fd0 --- /dev/null +++ b/vendor/golang.org/x/crypto/xtea/cipher.go @@ -0,0 +1,90 @@ +// 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++ + } +} |