diff options
Diffstat (limited to 'src/crypto/sha256/sha256.go')
-rw-r--r-- | src/crypto/sha256/sha256.go | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/src/crypto/sha256/sha256.go b/src/crypto/sha256/sha256.go new file mode 100644 index 000000000..d84cebf2f --- /dev/null +++ b/src/crypto/sha256/sha256.go @@ -0,0 +1,193 @@ +// 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. + +// Package sha256 implements the SHA224 and SHA256 hash algorithms as defined +// in FIPS 180-4. +package sha256 + +import ( + "crypto" + "hash" +) + +func init() { + crypto.RegisterHash(crypto.SHA224, New224) + crypto.RegisterHash(crypto.SHA256, New) +} + +// The size of a SHA256 checksum in bytes. +const Size = 32 + +// The size of a SHA224 checksum in bytes. +const Size224 = 28 + +// The blocksize of SHA256 and SHA224 in bytes. +const BlockSize = 64 + +const ( + chunk = 64 + init0 = 0x6A09E667 + init1 = 0xBB67AE85 + init2 = 0x3C6EF372 + init3 = 0xA54FF53A + init4 = 0x510E527F + init5 = 0x9B05688C + init6 = 0x1F83D9AB + init7 = 0x5BE0CD19 + init0_224 = 0xC1059ED8 + init1_224 = 0x367CD507 + init2_224 = 0x3070DD17 + init3_224 = 0xF70E5939 + init4_224 = 0xFFC00B31 + init5_224 = 0x68581511 + init6_224 = 0x64F98FA7 + init7_224 = 0xBEFA4FA4 +) + +// digest represents the partial evaluation of a checksum. +type digest struct { + h [8]uint32 + x [chunk]byte + nx int + len uint64 + is224 bool // mark if this digest is SHA-224 +} + +func (d *digest) Reset() { + if !d.is224 { + d.h[0] = init0 + d.h[1] = init1 + d.h[2] = init2 + d.h[3] = init3 + d.h[4] = init4 + d.h[5] = init5 + d.h[6] = init6 + d.h[7] = init7 + } else { + d.h[0] = init0_224 + d.h[1] = init1_224 + d.h[2] = init2_224 + d.h[3] = init3_224 + d.h[4] = init4_224 + d.h[5] = init5_224 + d.h[6] = init6_224 + d.h[7] = init7_224 + } + d.nx = 0 + d.len = 0 +} + +// New returns a new hash.Hash computing the SHA256 checksum. +func New() hash.Hash { + d := new(digest) + d.Reset() + return d +} + +// New224 returns a new hash.Hash computing the SHA224 checksum. +func New224() hash.Hash { + d := new(digest) + d.is224 = true + d.Reset() + return d +} + +func (d *digest) Size() int { + if !d.is224 { + return Size + } + return Size224 +} + +func (d *digest) BlockSize() int { return BlockSize } + +func (d *digest) Write(p []byte) (nn int, err error) { + nn = len(p) + d.len += uint64(nn) + if d.nx > 0 { + n := copy(d.x[d.nx:], p) + d.nx += n + if d.nx == chunk { + block(d, d.x[:]) + d.nx = 0 + } + p = p[n:] + } + if len(p) >= chunk { + n := len(p) &^ (chunk - 1) + block(d, p[:n]) + p = p[n:] + } + if len(p) > 0 { + d.nx = copy(d.x[:], p) + } + return +} + +func (d0 *digest) Sum(in []byte) []byte { + // Make a copy of d0 so that caller can keep writing and summing. + d := *d0 + hash := d.checkSum() + if d.is224 { + return append(in, hash[:Size224]...) + } + return append(in, hash[:]...) +} + +func (d *digest) checkSum() [Size]byte { + len := d.len + // Padding. Add a 1 bit and 0 bits until 56 bytes mod 64. + var tmp [64]byte + tmp[0] = 0x80 + if len%64 < 56 { + d.Write(tmp[0 : 56-len%64]) + } else { + d.Write(tmp[0 : 64+56-len%64]) + } + + // Length in bits. + len <<= 3 + for i := uint(0); i < 8; i++ { + tmp[i] = byte(len >> (56 - 8*i)) + } + d.Write(tmp[0:8]) + + if d.nx != 0 { + panic("d.nx != 0") + } + + h := d.h[:] + if d.is224 { + h = d.h[:7] + } + + var digest [Size]byte + for i, s := range h { + digest[i*4] = byte(s >> 24) + digest[i*4+1] = byte(s >> 16) + digest[i*4+2] = byte(s >> 8) + digest[i*4+3] = byte(s) + } + + return digest +} + +// Sum256 returns the SHA256 checksum of the data. +func Sum256(data []byte) [Size]byte { + var d digest + d.Reset() + d.Write(data) + return d.checkSum() +} + +// Sum224 returns the SHA224 checksum of the data. +func Sum224(data []byte) (sum224 [Size224]byte) { + var d digest + d.is224 = true + d.Reset() + d.Write(data) + sum := d.checkSum() + copy(sum224[:], sum[:Size224]) + return +} |