Copyright 2010 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 des implements the Data Encryption Standard (DES) and the Triple Data Encryption Algorithm (TDEA) as defined in U.S. Federal Information Processing Standards Publication 46-3. DES is cryptographically broken and should not be used for secure applications.
package des
Used to perform an initial permutation of a 64-bit input block.
var initialPermutation = [64]byte{
	6, 14, 22, 30, 38, 46, 54, 62,
	4, 12, 20, 28, 36, 44, 52, 60,
	2, 10, 18, 26, 34, 42, 50, 58,
	0, 8, 16, 24, 32, 40, 48, 56,
	7, 15, 23, 31, 39, 47, 55, 63,
	5, 13, 21, 29, 37, 45, 53, 61,
	3, 11, 19, 27, 35, 43, 51, 59,
	1, 9, 17, 25, 33, 41, 49, 57,
}
Used to perform a final permutation of a 4-bit preoutput block. This is the inverse of initialPermutation
var finalPermutation = [64]byte{
	24, 56, 16, 48, 8, 40, 0, 32,
	25, 57, 17, 49, 9, 41, 1, 33,
	26, 58, 18, 50, 10, 42, 2, 34,
	27, 59, 19, 51, 11, 43, 3, 35,
	28, 60, 20, 52, 12, 44, 4, 36,
	29, 61, 21, 53, 13, 45, 5, 37,
	30, 62, 22, 54, 14, 46, 6, 38,
	31, 63, 23, 55, 15, 47, 7, 39,
}
Used to expand an input block of 32 bits, producing an output block of 48 bits.
var expansionFunction = [48]byte{
	0, 31, 30, 29, 28, 27, 28, 27,
	26, 25, 24, 23, 24, 23, 22, 21,
	20, 19, 20, 19, 18, 17, 16, 15,
	16, 15, 14, 13, 12, 11, 12, 11,
	10, 9, 8, 7, 8, 7, 6, 5,
	4, 3, 4, 3, 2, 1, 0, 31,
}
Yields a 32-bit output from a 32-bit input
var permutationFunction = [32]byte{
	16, 25, 12, 11, 3, 20, 4, 15,
	31, 17, 9, 6, 27, 14, 1, 22,
	30, 24, 8, 18, 0, 5, 29, 23,
	13, 19, 2, 26, 10, 21, 28, 7,
}
Used in the key schedule to select 56 bits from a 64-bit input.
var permutedChoice1 = [56]byte{
	7, 15, 23, 31, 39, 47, 55, 63,
	6, 14, 22, 30, 38, 46, 54, 62,
	5, 13, 21, 29, 37, 45, 53, 61,
	4, 12, 20, 28, 1, 9, 17, 25,
	33, 41, 49, 57, 2, 10, 18, 26,
	34, 42, 50, 58, 3, 11, 19, 27,
	35, 43, 51, 59, 36, 44, 52, 60,
}
Used in the key schedule to produce each subkey by selecting 48 bits from the 56-bit input
var permutedChoice2 = [48]byte{
	42, 39, 45, 32, 55, 51, 53, 28,
	41, 50, 35, 46, 33, 37, 44, 52,
	30, 48, 40, 49, 29, 36, 43, 54,
	15, 4, 25, 19, 9, 1, 26, 16,
	5, 11, 23, 8, 12, 7, 17, 0,
	22, 3, 10, 14, 6, 20, 27, 24,
}
8 S-boxes composed of 4 rows and 16 columns Used in the DES cipher function
S-box 1
	{
		{14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7},
		{0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8},
		{4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0},
		{15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13},
S-box 2
	{
		{15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10},
		{3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5},
		{0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15},
		{13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9},
S-box 3
	{
		{10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8},
		{13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1},
		{13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7},
		{1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12},
S-box 4
	{
		{7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15},
		{13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9},
		{10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4},
		{3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14},
S-box 5
	{
		{2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9},
		{14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6},
		{4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14},
		{11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3},
S-box 6
	{
		{12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11},
		{10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8},
		{9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6},
		{4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13},
S-box 7
	{
		{4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1},
		{13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6},
		{1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2},
		{6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12},
S-box 8
	{
		{13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7},
		{1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2},
		{7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8},
		{2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11},
	},
}
Size of left rotation per round in each half of the key schedule