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v/vlib/crypto/sha256/sha256.v
2019-08-07 13:37:07 +02:00

215 lines
4.6 KiB
Go

// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
// Package sha256 implements the SHA224 and SHA256 hash algorithms as defined
// in FIPS 180-4.
// Based off: https://github.com/golang/go/tree/master/src/crypto/sha256
// Last commit: https://github.com/golang/go/commit/3ce865d7a0b88714cc433454ae2370a105210c01
module sha256
import encoding.binary
const (
// The size of a SHA256 checksum in bytes.
Size = 32
// The size of a SHA224 checksum in bytes.
Size224 = 28
// The blocksize of SHA256 and SHA224 in bytes.
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.
struct Digest {
mut:
h []u32
x []byte
nx int
len u64
is224 bool // mark if this digest is SHA-224
}
fn (d mut Digest) reset() {
d.h = [u32(0); 8]
d.x = [byte(0); Chunk]
if !d.is224 {
d.h[0] = u32(Init0)
d.h[1] = u32(Init1)
d.h[2] = u32(Init2)
d.h[3] = u32(Init3)
d.h[4] = u32(Init4)
d.h[5] = u32(Init5)
d.h[6] = u32(Init6)
d.h[7] = u32(Init7)
} else {
d.h[0] = u32(Init0_224)
d.h[1] = u32(Init1_224)
d.h[2] = u32(Init2_224)
d.h[3] = u32(Init3_224)
d.h[4] = u32(Init4_224)
d.h[5] = u32(Init5_224)
d.h[6] = u32(Init6_224)
d.h[7] = u32(Init7_224)
}
d.nx = 0
d.len = u64(0)
}
// new returns a new Digest (implementing hash.Hash) computing the SHA256 checksum.
pub fn new() *Digest {
mut d := &Digest{}
d.reset()
return d
}
// new224 returns a new Digest (implementing hash.Hash) computing the SHA224 checksum.
pub fn new224() *Digest {
mut d := &Digest{}
d.is224 = true
d.reset()
return d
}
fn (d mut Digest) write(p_ []byte) ?int {
mut p := p_
nn := p.len
d.len += u64(nn)
if d.nx > 0 {
n := copy(d.x.right(d.nx), p)
d.nx += n
if d.nx == Chunk {
block(mut d, d.x)
d.nx = 0
}
if n >= p.len {
p = []byte
} else {
p = p.right(n)
}
}
if p.len >= Chunk {
n := p.len &~ (Chunk - 1)
block(mut d, p.left(n))
if n >= p.len {
p = []byte
} else {
p = p.right(n)
}
}
if p.len > 0 {
d.nx = copy(d.x, p)
}
return nn
}
fn (d &Digest) sum(b_in mut []byte) []byte {
// Make a copy of d so that caller can keep writing and summing.
mut d0 := *d
hash := d0.checksum()
if d0.is224 {
for b in hash.left(Size224) {
b_in << b
}
} else {
for b in hash {
b_in << b
}
}
return *b_in
}
fn (d mut Digest) checksum() []byte {
mut len := d.len
// Padding. Add a 1 bit and 0 bits until 56 bytes mod 64.
mut tmp := [byte(0); 64]
tmp[0] = 0x80
if int(len)%64 < 56 {
d.write(tmp.left(56-int(len)%64))
} else {
d.write(tmp.left(64+56-int(len)%64))
}
// Length in bits.
len <<= u64(3)
binary.big_endian_put_u64(mut tmp, len)
d.write(tmp.left(8))
if d.nx != 0 {
panic('d.nx != 0')
}
digest := [byte(0); Size]
binary.big_endian_put_u32(mut digest, d.h[0])
binary.big_endian_put_u32(mut digest.right(4), d.h[1])
binary.big_endian_put_u32(mut digest.right(8), d.h[2])
binary.big_endian_put_u32(mut digest.right(12), d.h[3])
binary.big_endian_put_u32(mut digest.right(16), d.h[4])
binary.big_endian_put_u32(mut digest.right(20), d.h[5])
binary.big_endian_put_u32(mut digest.right(24), d.h[6])
if !d.is224 {
binary.big_endian_put_u32(mut digest.right(28), d.h[7])
}
return digest
}
// sum256 returns the SHA256 checksum of the data.
pub fn sum(data []byte) []byte {
return sum256(data)
}
// sum256 returns the SHA256 checksum of the data.
pub fn sum256(data []byte) []byte {
mut d := new()
d.write(data)
return d.checksum()
}
// sum224 returns the SHA224 checksum of the data.
pub fn sum224(data []byte) []byte {
mut d := new224()
d.write(data)
sum := d.checksum()
mut sum224 := [byte(0); Size224]
copy(sum224, sum.left(Size224))
return sum224
}
fn block(dig mut Digest, p []byte) {
// For now just use block_generic until we have specific
// architecture optimized versions
block_generic(mut dig, p)
}
pub fn (d &Digest) size() int {
if !d.is224 {
return Size
}
return Size224
}
pub fn (d &Digest) block_size() int { return BlockSize }