v/vlib/crypto/sha1/sha1.v

147 lines
2.8 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 sha1 implements the SHA-1 hash algorithm as defined in RFC 3174.
//
// SHA-1 is cryptographically broken and should not be used for secure
// applications.
// Adapted from: https://github.com/golang/go/blob/master/src/crypto/sha1
module sha1
import math
import encoding.binary
const(
// The size of a SHA-1 checksum in bytes.
Size = 20
// The blocksize of SHA-1 in bytes.
BlockSize = 64
)
const (
Chunk = 64
Init0 = 0x67452301
Init1 = 0xEFCDAB89
Init2 = 0x98BADCFE
Init3 = 0x10325476
Init4 = 0xC3D2E1F0
)
// digest represents the partial evaluation of a checksum.
struct Digest {
mut:
h []u32
x []byte
nx int
len u64
}
fn (d mut Digest) reset() {
d.x = [byte(0); Chunk]
d.h = [u32(0); 5]
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.nx = 0
d.len = u64(0)
}
// New returns a new Digest (implementing hash.Hash) computing the SHA1 checksum.
pub fn new() &Digest {
mut d := &Digest{}
d.reset()
return d
}
pub fn (d mut Digest) write(p []byte) ?int {
nn := p.len
d.len += u64(nn)
if d.nx > 0 {
n := int(math.min(f64(d.x.len), f64(p.len)))
for i:=0; i<n; i++ {
d.x.set(i+d.nx, p[i])
}
d.nx += n
if d.nx == Chunk {
block(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(d, p.left(n))
if n >= p.len {
p = []byte
} else {
p = p.right(n)
}
}
if p.len > 0 {
d.nx = int(math.min(f64(d.x.len), f64(p.len)))
for i:=0; i<d.nx; i++ {
d.x.set(i, p[i])
}
}
return nn
}
pub 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.check_sum()
for b in hash {
b_in << b
}
return *b_in
}
fn (d mut Digest) check_sum() []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(tmp, len)
d.write(tmp.left(8))
mut digest := [byte(0); Size]
binary.big_endian_put_u32(digest, d.h[0])
binary.big_endian_put_u32(digest.right(4), d.h[1])
binary.big_endian_put_u32(digest.right(8), d.h[2])
binary.big_endian_put_u32(digest.right(12), d.h[3])
binary.big_endian_put_u32(digest.right(16), d.h[4])
return digest
}
// Sum returns the SHA-1 checksum of the data.
pub fn sum(data []byte) []byte {
mut d := Digest{}
d.reset()
d.write(data)
return d.check_sum()
}
pub fn (d &Digest) size() int { return Size }
pub fn (d &Digest) block_size() int { return BlockSize }