mirror of
https://github.com/vbatts/go-mtree.git
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124 lines
2.6 KiB
Go
124 lines
2.6 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package ripemd160 implements the RIPEMD-160 hash algorithm.
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//
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// Deprecated: RIPEMD-160 is a legacy hash and should not be used for new
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// applications. Also, this package does not and will not provide an optimized
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// implementation. Instead, use a modern hash like SHA-256 (from crypto/sha256).
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package ripemd160 // import "golang.org/x/crypto/ripemd160"
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// RIPEMD-160 is designed by Hans Dobbertin, Antoon Bosselaers, and Bart
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// Preneel with specifications available at:
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// http://homes.esat.kuleuven.be/~cosicart/pdf/AB-9601/AB-9601.pdf.
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import (
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"crypto"
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"hash"
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)
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func init() {
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crypto.RegisterHash(crypto.RIPEMD160, New)
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}
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// The size of the checksum in bytes.
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const Size = 20
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// The block size of the hash algorithm in bytes.
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const BlockSize = 64
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const (
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_s0 = 0x67452301
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_s1 = 0xefcdab89
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_s2 = 0x98badcfe
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_s3 = 0x10325476
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_s4 = 0xc3d2e1f0
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)
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// digest represents the partial evaluation of a checksum.
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type digest struct {
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s [5]uint32 // running context
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x [BlockSize]byte // temporary buffer
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nx int // index into x
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tc uint64 // total count of bytes processed
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}
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func (d *digest) Reset() {
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d.s[0], d.s[1], d.s[2], d.s[3], d.s[4] = _s0, _s1, _s2, _s3, _s4
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d.nx = 0
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d.tc = 0
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}
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// New returns a new hash.Hash computing the checksum.
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func New() hash.Hash {
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result := new(digest)
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result.Reset()
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return result
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}
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func (d *digest) Size() int { return Size }
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func (d *digest) BlockSize() int { return BlockSize }
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func (d *digest) Write(p []byte) (nn int, err error) {
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nn = len(p)
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d.tc += uint64(nn)
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if d.nx > 0 {
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n := len(p)
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if n > BlockSize-d.nx {
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n = BlockSize - d.nx
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}
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for i := 0; i < n; i++ {
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d.x[d.nx+i] = p[i]
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}
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d.nx += n
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if d.nx == BlockSize {
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_Block(d, d.x[0:])
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d.nx = 0
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}
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p = p[n:]
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}
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n := _Block(d, p)
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p = p[n:]
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if len(p) > 0 {
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d.nx = copy(d.x[:], p)
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}
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return
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}
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func (d0 *digest) Sum(in []byte) []byte {
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// Make a copy of d0 so that caller can keep writing and summing.
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d := *d0
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// Padding. Add a 1 bit and 0 bits until 56 bytes mod 64.
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tc := d.tc
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var tmp [64]byte
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tmp[0] = 0x80
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if tc%64 < 56 {
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d.Write(tmp[0 : 56-tc%64])
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} else {
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d.Write(tmp[0 : 64+56-tc%64])
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}
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// Length in bits.
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tc <<= 3
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for i := uint(0); i < 8; i++ {
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tmp[i] = byte(tc >> (8 * i))
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}
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d.Write(tmp[0:8])
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if d.nx != 0 {
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panic("d.nx != 0")
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}
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var digest [Size]byte
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for i, s := range d.s {
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digest[i*4] = byte(s)
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digest[i*4+1] = byte(s >> 8)
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digest[i*4+2] = byte(s >> 16)
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digest[i*4+3] = byte(s >> 24)
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}
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return append(in, digest[:]...)
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}
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