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crypto/des: improve the throughput of DES and 3DES
For detailed explanation of the adopted (Eric Young's) algorithm, see http://ftp.nluug.nl/security/coast/libs/libdes/ALGORITHM benchmark old ns/op new ns/op delta BenchmarkEncrypt-16 649 164 -74.73% BenchmarkDecrypt-16 546 156 -71.43% BenchmarkTDESEncrypt-16 1651 385 -76.68% BenchmarkTDESDecrypt-16 1645 378 -77.02% benchmark old MB/s new MB/s speedup BenchmarkEncrypt-16 12.31 48.76 3.96x BenchmarkDecrypt-16 14.64 51.03 3.49x BenchmarkTDESEncrypt-16 4.84 20.74 4.29x BenchmarkTDESDecrypt-16 4.86 21.16 4.35x Change-Id: Ic3e1fe3340419ec5a0e6379434911eb41e0246f6 Reviewed-on: https://go-review.googlesource.com/36490 Run-TryBot: Minux Ma <minux@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>
This commit is contained in:
Mura Li
Russ Cox
parent
08bb7ccb75
commit
76d4274491
@ -4,25 +4,29 @@
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package des
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import (
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"encoding/binary"
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)
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import "encoding/binary"
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func cryptBlock(subkeys []uint64, dst, src []byte, decrypt bool) {
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b := binary.BigEndian.Uint64(src)
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b = permuteInitialBlock(b)
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left, right := uint32(b>>32), uint32(b)
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var subkey uint64
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for i := 0; i < 16; i++ {
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if decrypt {
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subkey = subkeys[15-i]
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} else {
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subkey = subkeys[i]
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}
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left = (left << 1) | (left >> 31)
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right = (right << 1) | (right >> 31)
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left, right = right, left^feistel(right, subkey)
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if decrypt {
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for i := 0; i < 8; i++ {
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left, right = feistel(left, right, subkeys[15-2*i], subkeys[15-(2*i+1)])
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}
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} else {
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for i := 0; i < 8; i++ {
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left, right = feistel(left, right, subkeys[2*i], subkeys[2*i+1])
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}
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}
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left = (left << 31) | (left >> 1)
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right = (right << 31) | (right >> 1)
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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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binary.BigEndian.PutUint64(dst, permuteFinalBlock(preOutput))
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@ -39,19 +43,34 @@ func decryptBlock(subkeys []uint64, dst, src []byte) {
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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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sBoxLocations := key ^ expandBlock(right)
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var sBoxResult uint32
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for i := uint8(0); i < 8; i++ {
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sBoxLocation := uint8(sBoxLocations>>42) & 0x3f
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sBoxLocations <<= 6
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// row determined by 1st and 6th bit
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// column is middle four bits
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row := (sBoxLocation & 0x1) | ((sBoxLocation & 0x20) >> 4)
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column := (sBoxLocation >> 1) & 0xf
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sBoxResult ^= feistelBox[i][16*row+column]
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}
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return sBoxResult
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func feistel(l, r uint32, k0, k1 uint64) (lout, rout uint32) {
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var t uint32
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t = r ^ uint32(k0>>32)
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l ^= feistelBox[7][t&0x3f] ^
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feistelBox[5][(t>>8)&0x3f] ^
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feistelBox[3][(t>>16)&0x3f] ^
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feistelBox[1][(t>>24)&0x3f]
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t = ((r << 28) | (r >> 4)) ^ uint32(k0)
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l ^= feistelBox[6][(t)&0x3f] ^
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feistelBox[4][(t>>8)&0x3f] ^
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feistelBox[2][(t>>16)&0x3f] ^
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feistelBox[0][(t>>24)&0x3f]
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t = l ^ uint32(k1>>32)
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r ^= feistelBox[7][t&0x3f] ^
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feistelBox[5][(t>>8)&0x3f] ^
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feistelBox[3][(t>>16)&0x3f] ^
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feistelBox[1][(t>>24)&0x3f]
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t = ((l << 28) | (l >> 4)) ^ uint32(k1)
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r ^= feistelBox[6][(t)&0x3f] ^
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feistelBox[4][(t>>8)&0x3f] ^
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feistelBox[2][(t>>16)&0x3f] ^
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feistelBox[0][(t>>24)&0x3f]
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return l, r
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}
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// feistelBox[s][16*i+j] contains the output of permutationFunction
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@ -73,27 +92,22 @@ func init() {
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for j := 0; j < 16; j++ {
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f := uint64(sBoxes[s][i][j]) << (4 * (7 - uint(s)))
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f = permuteBlock(f, permutationFunction[:])
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feistelBox[s][16*i+j] = uint32(f)
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// Row is determined by the 1st and 6th bit.
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// Column is the middle four bits.
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row := uint8(((i & 2) << 4) | i&1)
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col := uint8(j << 1)
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t := row | col
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// The rotation was performed in the feistel rounds, being factored out and now mixed into the feistelBox.
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f = (f << 1) | (f >> 31)
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feistelBox[s][t] = uint32(f)
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}
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}
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}
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}
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// expandBlock expands an input block of 32 bits,
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// producing an output block of 48 bits.
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func expandBlock(src uint32) (block uint64) {
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// rotate the 5 highest bits to the right.
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src = (src << 5) | (src >> 27)
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for i := 0; i < 8; i++ {
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block <<= 6
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// take the 6 bits on the right
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block |= uint64(src) & (1<<6 - 1)
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// advance by 4 bits.
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src = (src << 4) | (src >> 28)
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}
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return
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}
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// permuteInitialBlock is equivalent to the permutation defined
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// by initialPermutation.
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func permuteInitialBlock(block uint64) uint64 {
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@ -218,6 +232,24 @@ func (c *desCipher) generateSubkeys(keyBytes []byte) {
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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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c.subkeys[i] = permuteBlock(pc2Input, permutedChoice2[:])
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c.subkeys[i] = unpack(permuteBlock(pc2Input, permutedChoice2[:]))
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}
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}
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// Expand 48-bit input to 64-bit, with each 6-bit block padded by extra two bits at the top.
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// By doing so, we can have the input blocks (four bits each), and the key blocks (six bits each) well-aligned without
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// extra shifts/rotations for alignments.
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func unpack(x uint64) uint64 {
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var result uint64
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result = ((x>>(6*1))&0xff)<<(8*0) |
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((x>>(6*3))&0xff)<<(8*1) |
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((x>>(6*5))&0xff)<<(8*2) |
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((x>>(6*7))&0xff)<<(8*3) |
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((x>>(6*0))&0xff)<<(8*4) |
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((x>>(6*2))&0xff)<<(8*5) |
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((x>>(6*4))&0xff)<<(8*6) |
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((x>>(6*6))&0xff)<<(8*7)
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return result
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}
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@ -6,6 +6,7 @@ package des
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import (
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"crypto/cipher"
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"encoding/binary"
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"strconv"
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)
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@ -61,13 +62,51 @@ func NewTripleDESCipher(key []byte) (cipher.Block, error) {
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func (c *tripleDESCipher) BlockSize() int { return BlockSize }
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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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b := binary.BigEndian.Uint64(src)
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b = permuteInitialBlock(b)
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left, right := uint32(b>>32), uint32(b)
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left = (left << 1) | (left >> 31)
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right = (right << 1) | (right >> 31)
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for i := 0; i < 8; i++ {
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left, right = feistel(left, right, c.cipher1.subkeys[2*i], c.cipher1.subkeys[2*i+1])
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}
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for i := 0; i < 8; i++ {
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right, left = feistel(right, left, c.cipher2.subkeys[15-2*i], c.cipher2.subkeys[15-(2*i+1)])
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}
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for i := 0; i < 8; i++ {
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left, right = feistel(left, right, c.cipher3.subkeys[2*i], c.cipher3.subkeys[2*i+1])
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}
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left = (left << 31) | (left >> 1)
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right = (right << 31) | (right >> 1)
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preOutput := (uint64(right) << 32) | uint64(left)
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binary.BigEndian.PutUint64(dst, permuteFinalBlock(preOutput))
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}
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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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b := binary.BigEndian.Uint64(src)
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b = permuteInitialBlock(b)
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left, right := uint32(b>>32), uint32(b)
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left = (left << 1) | (left >> 31)
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right = (right << 1) | (right >> 31)
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for i := 0; i < 8; i++ {
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left, right = feistel(left, right, c.cipher3.subkeys[15-2*i], c.cipher3.subkeys[15-(2*i+1)])
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}
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for i := 0; i < 8; i++ {
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right, left = feistel(right, left, c.cipher2.subkeys[2*i], c.cipher2.subkeys[2*i+1])
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}
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for i := 0; i < 8; i++ {
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left, right = feistel(left, right, c.cipher1.subkeys[15-2*i], c.cipher1.subkeys[15-(2*i+1)])
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}
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left = (left << 31) | (left >> 1)
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right = (right << 31) | (right >> 1)
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preOutput := (uint64(right) << 32) | uint64(left)
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binary.BigEndian.PutUint64(dst, permuteFinalBlock(preOutput))
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}
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@ -1526,17 +1526,6 @@ func TestFinalPermute(t *testing.T) {
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}
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}
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func TestExpandBlock(t *testing.T) {
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for i := uint(0); i < 32; i++ {
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bit := uint32(1) << i
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got := expandBlock(bit)
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want := permuteBlock(uint64(bit), expansionFunction[:])
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if got != want {
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t.Errorf("expand(%x) = %x, want %x", bit, got, want)
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}
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}
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}
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func BenchmarkEncrypt(b *testing.B) {
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tt := encryptDESTests[0]
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c, err := NewCipher(tt.key)
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@ -1564,3 +1553,31 @@ func BenchmarkDecrypt(b *testing.B) {
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c.Decrypt(out, tt.out)
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}
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}
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func BenchmarkTDESEncrypt(b *testing.B) {
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tt := encryptTripleDESTests[0]
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c, err := NewTripleDESCipher(tt.key)
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if err != nil {
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b.Fatal("NewCipher:", err)
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}
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out := make([]byte, len(tt.in))
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b.SetBytes(int64(len(out)))
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b.ResetTimer()
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for i := 0; i < b.N; i++ {
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c.Encrypt(out, tt.in)
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}
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}
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func BenchmarkTDESDecrypt(b *testing.B) {
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tt := encryptTripleDESTests[0]
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c, err := NewTripleDESCipher(tt.key)
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if err != nil {
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b.Fatal("NewCipher:", err)
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}
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out := make([]byte, len(tt.out))
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b.SetBytes(int64(len(out)))
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b.ResetTimer()
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for i := 0; i < b.N; i++ {
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c.Decrypt(out, tt.out)
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}
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}
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