code review 4315050: crypto/des: cleanups

src/pkg/crypto/des/const.go

 // 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.
 package des
 
-// Used to perform an initial permutation of a
-// 64-bit input block
-var initialPermutation = [64]uint8{
-        58, 50, 42, 34, 26, 18, 10, 2,
-        60, 52, 44, 36, 28, 20, 12, 4,
-        62, 54, 46, 38, 30, 22, 14, 6,
-        64, 56, 48, 40, 32, 24, 16, 8,
-        57, 49, 41, 33, 25, 17, 9, 1,
-        59, 51, 43, 35, 27, 19, 11, 3,
-        61, 53, 45, 37, 29, 21, 13, 5,
-        63, 55, 47, 39, 31, 23, 15, 7}
+// 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
-// 64-bit preoutput block
-// This is the inverse of initialPermutation
-var finalPermutation = [64]uint8{
-        40, 8, 48, 16, 56, 24, 64, 32,
-        39, 7, 47, 15, 55, 23, 63, 31,
-        38, 6, 46, 14, 54, 22, 62, 30,
-        37, 5, 45, 13, 53, 21, 61, 29,
-        36, 4, 44, 12, 52, 20, 60, 28,
-        35, 3, 43, 11, 51, 19, 59, 27,
-        34, 2, 42, 10, 50, 18, 58, 26,
-        33, 1, 41, 9, 49, 17, 57, 25}
+// 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]uint8{
-        32, 1, 2, 3, 4, 5,
-        4, 5, 6, 7, 8, 9,
-        8, 9, 10, 11, 12, 13,
-        12, 13, 14, 15, 16, 17,
-        16, 17, 18, 19, 20, 21,
-        20, 21, 22, 23, 24, 25,
-        24, 25, 26, 27, 28, 29,
-        28, 29, 30, 31, 32, 1}
+// 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]uint8{
-        16, 7, 20, 21,
-        29, 12, 28, 17,
-        1, 15, 23, 26,
-        5, 18, 31, 10,
-        2, 8, 24, 14,
-        32, 27, 3, 9,
-        19, 13, 30, 6,
-        22, 11, 4, 25}
+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]uint8{
-        // left
-        57, 49, 41, 33, 25, 17, 9,
-        1, 58, 50, 42, 34, 26, 18,
-        10, 2, 59, 51, 43, 35, 27,
-        19, 11, 3, 60, 52, 44, 36,
-        // right
-        63, 55, 47, 39, 31, 23, 15,
-        7, 62, 54, 46, 38, 30, 22,
-        14, 6, 61, 53, 45, 37, 29,
-        21, 13, 5, 28, 20, 12, 4}
+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]uint8{
-        14, 17, 11, 24, 1, 5,
-        3, 28, 15, 6, 21, 10,
-        23, 19, 12, 4, 26, 8,
-        16, 7, 27, 20, 13, 2,
-        41, 52, 31, 37, 47, 55,
-        30, 40, 51, 45, 33, 48,
-        44, 49, 39, 56, 34, 53,
-        46, 42, 50, 36, 29, 32}
+// 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
 var sBoxes = [8][4][16]uint8{
         // S-box 1
         {
-                [16]uint8{14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7},
-                [16]uint8{0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8},
-                [16]uint8{4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0},
-                [16]uint8{15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13}},
+                {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
         {
-                [16]uint8{15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10},
-                [16]uint8{3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5},
-                [16]uint8{0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15},
-                [16]uint8{13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9}},
+                {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
         {
-                [16]uint8{10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8},
-                [16]uint8{13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1},
-                [16]uint8{13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7},
-                [16]uint8{1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12}},
+                {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
         {
-                [16]uint8{7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15},
-                [16]uint8{13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9},
-                [16]uint8{10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4},
-                [16]uint8{3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14}},
+                {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
         {
-                [16]uint8{2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9},
-                [16]uint8{14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6},
-                [16]uint8{4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14},
-                [16]uint8{11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3}},
+                {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
         {
-                [16]uint8{12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11},
-                [16]uint8{10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8},
-                [16]uint8{9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6},
-                [16]uint8{4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13}},
+                {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
         {
-                [16]uint8{4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1},
-                [16]uint8{13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6},
-                [16]uint8{1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2},
-                [16]uint8{6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12}},
+                {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
         {
-                [16]uint8{13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7},
-                [16]uint8{1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2},
-                [16]uint8{7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8},
-                [16]uint8{2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11}}}
+                {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
 var ksRotations = [16]uint8{1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1}