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crypto/des: new package providing implementations of DES and TDEA
Original code by Chris Lennert <cale...@gmail.com> R=rsc, agl1 CC=golang-dev https://golang.org/cl/4331054
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13
src/pkg/crypto/des/Makefile
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13
src/pkg/crypto/des/Makefile
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# Copyright 2010 The Go Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style
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# license that can be found in the LICENSE file.
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include ../../../Make.inc
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TARG=crypto/des
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GOFILES=\
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block.go\
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cipher.go\
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const.go\
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include ../../../Make.pkg
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130
src/pkg/crypto/des/block.go
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130
src/pkg/crypto/des/block.go
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// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package des
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// Encrypt one block from src into dst, using the subkeys.
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func encryptBlock(subkeys [16]uint64, dst, src []byte) {
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// perform initial permutation
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permutedSrc := permuteBlock(src, initialPermutation[0:])
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// split into left and right halves
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left := uint32(permutedSrc >> 32)
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right := uint32(permutedSrc)
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// process left and right with feistel function
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for i := 0; i < 16; i++ {
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previousRight := right
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right = left ^ feistel(right, subkeys[i])
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left = previousRight
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}
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// switch left & right and perform final permutation
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preOutput := (uint64(right) << 32) | uint64(left)
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final := uint64ToBytes(permuteBlock(uint64ToBytes(preOutput), finalPermutation[0:]))
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// copy bytes to destination
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copy(dst, final)
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}
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// Decrypt one block from src into dst, using the subkeys.
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func decryptBlock(subkeys [16]uint64, dst, src []byte) {
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// perform initial permutation
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permutedSrc := permuteBlock(src, initialPermutation[0:])
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// split into left and right halves
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left := uint32(permutedSrc >> 32)
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right := uint32(permutedSrc)
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// process left and right with feistel function
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for i := 0; i < 16; i++ {
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previousRight := right
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// decryption reverses order of subkeys
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right = left ^ feistel(right, subkeys[15-i])
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left = previousRight
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}
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// switch left & right and perform final permutation
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preOutput := (uint64(right) << 32) | uint64(left)
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final := uint64ToBytes(permuteBlock(uint64ToBytes(preOutput), finalPermutation[0:]))
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// copy bytes to destination
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copy(dst, final)
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}
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// DES Feistel function
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func feistel(right uint32, key uint64) (result uint32) {
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rightExpanded := permuteBlock(uint32ToBytes(right), expansionFunction[:])
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xorResult := key ^ rightExpanded
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var sBoxResult uint32
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for i := uint8(0); i < 8; i++ {
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sBoxCoordValue := uint8((xorResult << (16 + (6 * i))) >> 58)
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// determine the proper S-box row and column from the 6-bits of
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// sBoxCoordValue row is determined by 1st and 6th bit
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row := (sBoxCoordValue & 0x1) | ((sBoxCoordValue & 0x20) >> 4)
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// column is middle four bits
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column := (sBoxCoordValue << 3) >> 4
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sBoxResult |= uint32(sBoxes[i][row][column]) << (4 * (7 - i))
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}
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return uint32(permuteBlock(uint32ToBytes(sBoxResult), permutationFunction[0:]))
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}
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// general purpose function to perform DES block permutations
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func permuteBlock(src []byte, permutation []uint8) (block uint64) {
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for finalPosition, bitNumber := range permutation {
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bitIndex := bitNumber - 1
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byteIndex := bitIndex >> 3
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bitNumberInByte := bitIndex % 8
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bitValue := (src[byteIndex] << bitNumberInByte) >> 7
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block |= uint64(bitValue) << uint64((uint8(len(permutation)-1))-uint8(finalPosition))
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}
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return
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}
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// creates 16 28-bit blocks rotated according
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// to the rotation schedule
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func ksRotate(in uint32) (out []uint32) {
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out = make([]uint32, 16)
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last := in
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for i := 0; i < 16; i++ {
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// 28-bit circular left shift
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part1 := (last << (4 + uint32(ksRotations[i]))) >> 4
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part2 := (last << 4) >> (32 - ksRotations[i])
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out[i] = part1 | part2
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last = out[i]
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}
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return
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}
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// creates 16 56-bit subkeys from the original key
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func ksGenerateSubkeys(cipher *DESCipher) {
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// apply PC1 permutation to key
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permutedKey := permuteBlock(cipher.key, permutedChoice1[0:])
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// rotate halves of permuted key according to the rotation schedule
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leftRotations := ksRotate(uint32(permutedKey >> 28))
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rightRotations := ksRotate(uint32(permutedKey<<4) >> 4)
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// generate subkeys
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for i := 0; i < 16; i++ {
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// combine halves to form 56-bit input to PC2
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pc2Input := uint64(leftRotations[i])<<28 | uint64(rightRotations[i])
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// apply PC2 permutation to 7 byte input
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cipher.subkeys[i] = permuteBlock(uint64ToBytes(pc2Input)[1:], permutedChoice2[0:])
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}
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}
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// generates a byte array from uint32 input
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func uint32ToBytes(block uint32) []byte {
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return []byte{
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byte(block >> 24), byte(block >> 16),
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byte(block >> 8), byte(block)}
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}
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// generates a byte array from uint64 input
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func uint64ToBytes(block uint64) []byte {
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return []byte{
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byte(block >> 56), byte(block >> 48),
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byte(block >> 40), byte(block >> 32),
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byte(block >> 24), byte(block >> 16),
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byte(block >> 8), byte(block)}
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}
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113
src/pkg/crypto/des/cipher.go
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113
src/pkg/crypto/des/cipher.go
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// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package des
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import (
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"os"
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"strconv"
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)
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// The DES block size in bytes.
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const BlockSize = 8
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type KeySizeError int
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func (k KeySizeError) String() string {
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return "crypto/des: invalid key size " + strconv.Itoa(int(k))
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}
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// A DESCipher is an instance of DES encryption.
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type DESCipher struct {
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key []byte
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subkeys [16]uint64
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}
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// NewCipher creates and returns a new Cipher.
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func NewDESCipher(key []byte) (*DESCipher, os.Error) {
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k := len(key)
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if k != 8 {
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return nil, KeySizeError(k)
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}
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c := &DESCipher{key, [16]uint64{}}
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ksGenerateSubkeys(c)
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return c, nil
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}
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// BlockSize returns the DES block size, 8 bytes.
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func (c *DESCipher) BlockSize() int { return BlockSize }
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// Encrypts the 8-byte buffer src and stores the result in dst.
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// Note that for amounts of data larger than a block,
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// it is not safe to just call Encrypt on successive blocks;
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// instead, use an encryption mode like CBC (see crypto/cipher/cbc.go).
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func (c *DESCipher) Encrypt(dst, src []byte) { encryptBlock(c.subkeys, dst, src) }
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// Decrypts the 8-byte buffer src and stores the result in dst.
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func (c *DESCipher) Decrypt(dst, src []byte) { decryptBlock(c.subkeys, dst, src) }
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// Reset zeros the key data, so that it will no longer
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// appear in the process's memory.
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func (c *DESCipher) Reset() {
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for i := 0; i < len(c.key); i++ {
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c.key[i] = 0
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}
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for i := 0; i < len(c.subkeys); i++ {
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c.subkeys[i] = 0
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}
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}
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// A TripleDESCipher is an instance of TripleDES encryption.
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type TripleDESCipher struct {
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key []byte
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cipher1, cipher2, cipher3 *DESCipher
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}
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// NewCipher creates and returns a new Cipher.
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func NewTripleDESCipher(key []byte) (*TripleDESCipher, os.Error) {
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k := len(key)
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if k != 24 {
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return nil, KeySizeError(k)
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}
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cipher1, _ := NewDESCipher(key[0:8])
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cipher2, _ := NewDESCipher(key[8:16])
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cipher3, _ := NewDESCipher(key[16:])
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c := &TripleDESCipher{key, cipher1, cipher2, cipher3}
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return c, nil
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}
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// BlockSize returns the TripleDES block size, 8 bytes.
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// It is necessary to satisfy the Block interface in the
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// package "crypto/cipher".
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func (c *TripleDESCipher) BlockSize() int { return BlockSize }
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// Encrypts the 8-byte buffer src and stores the result in dst.
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// Note that for amounts of data larger than a block,
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// it is not safe to just call Encrypt on successive blocks;
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// instead, use an encryption mode like CBC (see crypto/cipher/cbc.go).
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func (c *TripleDESCipher) Encrypt(dst, src []byte) {
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c.cipher1.Encrypt(dst, src)
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c.cipher2.Decrypt(dst, dst)
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c.cipher3.Encrypt(dst, dst)
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}
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// Decrypts the 8-byte buffer src and stores the result in dst.
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func (c *TripleDESCipher) Decrypt(dst, src []byte) {
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c.cipher3.Decrypt(dst, src)
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c.cipher2.Encrypt(dst, dst)
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c.cipher1.Decrypt(dst, dst)
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}
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// Reset zeros the key data, so that it will no longer
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// appear in the process's memory.
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func (c *TripleDESCipher) Reset() {
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for i := 0; i < len(c.key); i++ {
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c.key[i] = 0
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}
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c.cipher1.Reset()
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c.cipher2.Reset()
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c.cipher3.Reset()
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}
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138
src/pkg/crypto/des/const.go
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138
src/pkg/crypto/des/const.go
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// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package des implements the Data Encryption Standard (DES) and the
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// Triple Data Encryption Algorithm (TDEA) as defined
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// in U.S. Federal Information Processing Standards Publication 46-3.
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package des
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// Used to perform an initial permutation of a
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// 64-bit input block
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var initialPermutation = [64]uint8{
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58, 50, 42, 34, 26, 18, 10, 2,
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60, 52, 44, 36, 28, 20, 12, 4,
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62, 54, 46, 38, 30, 22, 14, 6,
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64, 56, 48, 40, 32, 24, 16, 8,
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57, 49, 41, 33, 25, 17, 9, 1,
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59, 51, 43, 35, 27, 19, 11, 3,
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61, 53, 45, 37, 29, 21, 13, 5,
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63, 55, 47, 39, 31, 23, 15, 7}
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// Used to perform a final permutation of a
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// 64-bit preoutput block
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// This is the inverse of initialPermutation
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var finalPermutation = [64]uint8{
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40, 8, 48, 16, 56, 24, 64, 32,
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39, 7, 47, 15, 55, 23, 63, 31,
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38, 6, 46, 14, 54, 22, 62, 30,
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37, 5, 45, 13, 53, 21, 61, 29,
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36, 4, 44, 12, 52, 20, 60, 28,
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35, 3, 43, 11, 51, 19, 59, 27,
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34, 2, 42, 10, 50, 18, 58, 26,
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33, 1, 41, 9, 49, 17, 57, 25}
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// Used to expand an input block of 32 bits,
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// producing an output block of 48 bits.
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var expansionFunction = [48]uint8{
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32, 1, 2, 3, 4, 5,
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4, 5, 6, 7, 8, 9,
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8, 9, 10, 11, 12, 13,
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12, 13, 14, 15, 16, 17,
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16, 17, 18, 19, 20, 21,
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20, 21, 22, 23, 24, 25,
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24, 25, 26, 27, 28, 29,
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28, 29, 30, 31, 32, 1}
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// Yields a 32-bit output from a 32-bit input
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var permutationFunction = [32]uint8{
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16, 7, 20, 21,
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29, 12, 28, 17,
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1, 15, 23, 26,
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5, 18, 31, 10,
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2, 8, 24, 14,
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32, 27, 3, 9,
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19, 13, 30, 6,
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22, 11, 4, 25}
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// Used in the key schedule to select 56 bits
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// from a 64-bit input.
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var permutedChoice1 = [56]uint8{
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// left
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57, 49, 41, 33, 25, 17, 9,
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1, 58, 50, 42, 34, 26, 18,
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10, 2, 59, 51, 43, 35, 27,
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19, 11, 3, 60, 52, 44, 36,
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// right
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63, 55, 47, 39, 31, 23, 15,
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7, 62, 54, 46, 38, 30, 22,
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14, 6, 61, 53, 45, 37, 29,
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21, 13, 5, 28, 20, 12, 4}
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// Used in the key schedule to produce
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// each subkey by selecting 48 bits
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// from the 56-bit input
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var permutedChoice2 = [48]uint8{
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14, 17, 11, 24, 1, 5,
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3, 28, 15, 6, 21, 10,
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23, 19, 12, 4, 26, 8,
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16, 7, 27, 20, 13, 2,
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41, 52, 31, 37, 47, 55,
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30, 40, 51, 45, 33, 48,
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44, 49, 39, 56, 34, 53,
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46, 42, 50, 36, 29, 32}
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// 8 S-boxes composed of 4 rows and 16 columns
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// Used in the DES cipher function
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var sBoxes = [8][4][16]uint8{
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// S-box 1
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{
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[16]uint8{14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7},
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[16]uint8{0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8},
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[16]uint8{4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0},
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[16]uint8{15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13}},
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// S-box 2
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{
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[16]uint8{15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10},
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[16]uint8{3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5},
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[16]uint8{0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15},
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[16]uint8{13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9}},
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// S-box 3
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{
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[16]uint8{10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8},
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[16]uint8{13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1},
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[16]uint8{13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7},
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[16]uint8{1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12}},
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// S-box 4
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{
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[16]uint8{7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15},
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[16]uint8{13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9},
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[16]uint8{10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4},
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[16]uint8{3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14}},
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// S-box 5
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{
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[16]uint8{2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9},
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[16]uint8{14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6},
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[16]uint8{4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14},
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[16]uint8{11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3}},
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// S-box 6
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{
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[16]uint8{12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11},
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[16]uint8{10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8},
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[16]uint8{9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6},
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[16]uint8{4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13}},
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// S-box 7
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{
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[16]uint8{4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1},
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[16]uint8{13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6},
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[16]uint8{1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2},
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[16]uint8{6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12}},
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// S-box 8
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{
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[16]uint8{13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7},
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[16]uint8{1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2},
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[16]uint8{7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8},
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[16]uint8{2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11}}}
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|
||||
// Size of left rotation per round in each half of the key schedule
|
||||
var ksRotations = [16]uint8{1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1}
|
1595
src/pkg/crypto/des/des_test.go
Normal file
1595
src/pkg/crypto/des/des_test.go
Normal file
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Block a user