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Diffstat (limited to 'libgo/go/crypto/aes/block.go')
| -rw-r--r-- | libgo/go/crypto/aes/block.go | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/libgo/go/crypto/aes/block.go b/libgo/go/crypto/aes/block.go new file mode 100644 index 000000000..130cd011c --- /dev/null +++ b/libgo/go/crypto/aes/block.go @@ -0,0 +1,176 @@ +// 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. + +// This Go implementation is derived in part from the reference +// ANSI C implementation, which carries the following notice: +// +// rijndael-alg-fst.c +// +// @version 3.0 (December 2000) +// +// Optimised ANSI C code for the Rijndael cipher (now AES) +// +// @author Vincent Rijmen <vincent.rijmen@esat.kuleuven.ac.be> +// @author Antoon Bosselaers <antoon.bosselaers@esat.kuleuven.ac.be> +// @author Paulo Barreto <paulo.barreto@terra.com.br> +// +// This code is hereby placed in the public domain. +// +// THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY EXPRESS +// OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +// ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE +// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR +// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, +// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE +// OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, +// EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +// +// See FIPS 197 for specification, and see Daemen and Rijmen's Rijndael submission +// for implementation details. +// http://www.csrc.nist.gov/publications/fips/fips197/fips-197.pdf +// http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf + +package aes + +// Encrypt one block from src into dst, using the expanded key xk. +func encryptBlock(xk []uint32, dst, src []byte) { + var s0, s1, s2, s3, t0, t1, t2, t3 uint32 + + s0 = uint32(src[0])<<24 | uint32(src[1])<<16 | uint32(src[2])<<8 | uint32(src[3]) + s1 = uint32(src[4])<<24 | uint32(src[5])<<16 | uint32(src[6])<<8 | uint32(src[7]) + s2 = uint32(src[8])<<24 | uint32(src[9])<<16 | uint32(src[10])<<8 | uint32(src[11]) + s3 = uint32(src[12])<<24 | uint32(src[13])<<16 | uint32(src[14])<<8 | uint32(src[15]) + + // First round just XORs input with key. + s0 ^= xk[0] + s1 ^= xk[1] + s2 ^= xk[2] + s3 ^= xk[3] + + // Middle rounds shuffle using tables. + // Number of rounds is set by length of expanded key. + nr := len(xk)/4 - 2 // - 2: one above, one more below + k := 4 + for r := 0; r < nr; r++ { + t0 = xk[k+0] ^ te[0][s0>>24] ^ te[1][s1>>16&0xff] ^ te[2][s2>>8&0xff] ^ te[3][s3&0xff] + t1 = xk[k+1] ^ te[0][s1>>24] ^ te[1][s2>>16&0xff] ^ te[2][s3>>8&0xff] ^ te[3][s0&0xff] + t2 = xk[k+2] ^ te[0][s2>>24] ^ te[1][s3>>16&0xff] ^ te[2][s0>>8&0xff] ^ te[3][s1&0xff] + t3 = xk[k+3] ^ te[0][s3>>24] ^ te[1][s0>>16&0xff] ^ te[2][s1>>8&0xff] ^ te[3][s2&0xff] + k += 4 + s0, s1, s2, s3 = t0, t1, t2, t3 + } + + // Last round uses s-box directly and XORs to produce output. + s0 = uint32(sbox0[t0>>24])<<24 | uint32(sbox0[t1>>16&0xff])<<16 | uint32(sbox0[t2>>8&0xff])<<8 | uint32(sbox0[t3&0xff]) + s1 = uint32(sbox0[t1>>24])<<24 | uint32(sbox0[t2>>16&0xff])<<16 | uint32(sbox0[t3>>8&0xff])<<8 | uint32(sbox0[t0&0xff]) + s2 = uint32(sbox0[t2>>24])<<24 | uint32(sbox0[t3>>16&0xff])<<16 | uint32(sbox0[t0>>8&0xff])<<8 | uint32(sbox0[t1&0xff]) + s3 = uint32(sbox0[t3>>24])<<24 | uint32(sbox0[t0>>16&0xff])<<16 | uint32(sbox0[t1>>8&0xff])<<8 | uint32(sbox0[t2&0xff]) + + s0 ^= xk[k+0] + s1 ^= xk[k+1] + s2 ^= xk[k+2] + s3 ^= xk[k+3] + + dst[0], dst[1], dst[2], dst[3] = byte(s0>>24), byte(s0>>16), byte(s0>>8), byte(s0) + dst[4], dst[5], dst[6], dst[7] = byte(s1>>24), byte(s1>>16), byte(s1>>8), byte(s1) + dst[8], dst[9], dst[10], dst[11] = byte(s2>>24), byte(s2>>16), byte(s2>>8), byte(s2) + dst[12], dst[13], dst[14], dst[15] = byte(s3>>24), byte(s3>>16), byte(s3>>8), byte(s3) +} + +// Decrypt one block from src into dst, using the expanded key xk. +func decryptBlock(xk []uint32, dst, src []byte) { + var s0, s1, s2, s3, t0, t1, t2, t3 uint32 + + s0 = uint32(src[0])<<24 | uint32(src[1])<<16 | uint32(src[2])<<8 | uint32(src[3]) + s1 = uint32(src[4])<<24 | uint32(src[5])<<16 | uint32(src[6])<<8 | uint32(src[7]) + s2 = uint32(src[8])<<24 | uint32(src[9])<<16 | uint32(src[10])<<8 | uint32(src[11]) + s3 = uint32(src[12])<<24 | uint32(src[13])<<16 | uint32(src[14])<<8 | uint32(src[15]) + + // First round just XORs input with key. + s0 ^= xk[0] + s1 ^= xk[1] + s2 ^= xk[2] + s3 ^= xk[3] + + // Middle rounds shuffle using tables. + // Number of rounds is set by length of expanded key. + nr := len(xk)/4 - 2 // - 2: one above, one more below + k := 4 + for r := 0; r < nr; r++ { + t0 = xk[k+0] ^ td[0][s0>>24] ^ td[1][s3>>16&0xff] ^ td[2][s2>>8&0xff] ^ td[3][s1&0xff] + t1 = xk[k+1] ^ td[0][s1>>24] ^ td[1][s0>>16&0xff] ^ td[2][s3>>8&0xff] ^ td[3][s2&0xff] + t2 = xk[k+2] ^ td[0][s2>>24] ^ td[1][s1>>16&0xff] ^ td[2][s0>>8&0xff] ^ td[3][s3&0xff] + t3 = xk[k+3] ^ td[0][s3>>24] ^ td[1][s2>>16&0xff] ^ td[2][s1>>8&0xff] ^ td[3][s0&0xff] + k += 4 + s0, s1, s2, s3 = t0, t1, t2, t3 + } + + // Last round uses s-box directly and XORs to produce output. + s0 = uint32(sbox1[t0>>24])<<24 | uint32(sbox1[t3>>16&0xff])<<16 | uint32(sbox1[t2>>8&0xff])<<8 | uint32(sbox1[t1&0xff]) + s1 = uint32(sbox1[t1>>24])<<24 | uint32(sbox1[t0>>16&0xff])<<16 | uint32(sbox1[t3>>8&0xff])<<8 | uint32(sbox1[t2&0xff]) + s2 = uint32(sbox1[t2>>24])<<24 | uint32(sbox1[t1>>16&0xff])<<16 | uint32(sbox1[t0>>8&0xff])<<8 | uint32(sbox1[t3&0xff]) + s3 = uint32(sbox1[t3>>24])<<24 | uint32(sbox1[t2>>16&0xff])<<16 | uint32(sbox1[t1>>8&0xff])<<8 | uint32(sbox1[t0&0xff]) + + s0 ^= xk[k+0] + s1 ^= xk[k+1] + s2 ^= xk[k+2] + s3 ^= xk[k+3] + + dst[0], dst[1], dst[2], dst[3] = byte(s0>>24), byte(s0>>16), byte(s0>>8), byte(s0) + dst[4], dst[5], dst[6], dst[7] = byte(s1>>24), byte(s1>>16), byte(s1>>8), byte(s1) + dst[8], dst[9], dst[10], dst[11] = byte(s2>>24), byte(s2>>16), byte(s2>>8), byte(s2) + dst[12], dst[13], dst[14], dst[15] = byte(s3>>24), byte(s3>>16), byte(s3>>8), byte(s3) +} + +// Apply sbox0 to each byte in w. +func subw(w uint32) uint32 { + return uint32(sbox0[w>>24])<<24 | + uint32(sbox0[w>>16&0xff])<<16 | + uint32(sbox0[w>>8&0xff])<<8 | + uint32(sbox0[w&0xff]) +} + +// Rotate +func rotw(w uint32) uint32 { return w<<8 | w>>24 } + +// Key expansion algorithm. See FIPS-197, Figure 11. +// Their rcon[i] is our powx[i-1] << 24. +func expandKey(key []byte, enc, dec []uint32) { + // Encryption key setup. + var i int + nk := len(key) / 4 + for i = 0; i < nk; i++ { + enc[i] = uint32(key[4*i])<<24 | uint32(key[4*i+1])<<16 | uint32(key[4*i+2])<<8 | uint32(key[4*i+3]) + } + for ; i < len(enc); i++ { + t := enc[i-1] + if i%nk == 0 { + t = subw(rotw(t)) ^ (uint32(powx[i/nk-1]) << 24) + } else if nk > 6 && i%nk == 4 { + t = subw(t) + } + enc[i] = enc[i-nk] ^ t + } + + // Derive decryption key from encryption key. + // Reverse the 4-word round key sets from enc to produce dec. + // All sets but the first and last get the MixColumn transform applied. + if dec == nil { + return + } + n := len(enc) + for i := 0; i < n; i += 4 { + ei := n - i - 4 + for j := 0; j < 4; j++ { + x := enc[ei+j] + if i > 0 && i+4 < n { + x = td[0][sbox0[x>>24]] ^ td[1][sbox0[x>>16&0xff]] ^ td[2][sbox0[x>>8&0xff]] ^ td[3][sbox0[x&0xff]] + } + dec[i+j] = x + } + } +} |