github.com/graybobo/golang.org-package-offline-cache@v0.0.0-20200626051047-6608995c132f/x/crypto/ripemd160/ripemd160.go (about)

     1  // Copyright 2010 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package ripemd160 implements the RIPEMD-160 hash algorithm.
     6  package ripemd160 // import "golang.org/x/crypto/ripemd160"
     7  
     8  // RIPEMD-160 is designed by by Hans Dobbertin, Antoon Bosselaers, and Bart
     9  // Preneel with specifications available at:
    10  // http://homes.esat.kuleuven.be/~cosicart/pdf/AB-9601/AB-9601.pdf.
    11  
    12  import (
    13  	"crypto"
    14  	"hash"
    15  )
    16  
    17  func init() {
    18  	crypto.RegisterHash(crypto.RIPEMD160, New)
    19  }
    20  
    21  // The size of the checksum in bytes.
    22  const Size = 20
    23  
    24  // The block size of the hash algorithm in bytes.
    25  const BlockSize = 64
    26  
    27  const (
    28  	_s0 = 0x67452301
    29  	_s1 = 0xefcdab89
    30  	_s2 = 0x98badcfe
    31  	_s3 = 0x10325476
    32  	_s4 = 0xc3d2e1f0
    33  )
    34  
    35  // digest represents the partial evaluation of a checksum.
    36  type digest struct {
    37  	s  [5]uint32       // running context
    38  	x  [BlockSize]byte // temporary buffer
    39  	nx int             // index into x
    40  	tc uint64          // total count of bytes processed
    41  }
    42  
    43  func (d *digest) Reset() {
    44  	d.s[0], d.s[1], d.s[2], d.s[3], d.s[4] = _s0, _s1, _s2, _s3, _s4
    45  	d.nx = 0
    46  	d.tc = 0
    47  }
    48  
    49  // New returns a new hash.Hash computing the checksum.
    50  func New() hash.Hash {
    51  	result := new(digest)
    52  	result.Reset()
    53  	return result
    54  }
    55  
    56  func (d *digest) Size() int { return Size }
    57  
    58  func (d *digest) BlockSize() int { return BlockSize }
    59  
    60  func (d *digest) Write(p []byte) (nn int, err error) {
    61  	nn = len(p)
    62  	d.tc += uint64(nn)
    63  	if d.nx > 0 {
    64  		n := len(p)
    65  		if n > BlockSize-d.nx {
    66  			n = BlockSize - d.nx
    67  		}
    68  		for i := 0; i < n; i++ {
    69  			d.x[d.nx+i] = p[i]
    70  		}
    71  		d.nx += n
    72  		if d.nx == BlockSize {
    73  			_Block(d, d.x[0:])
    74  			d.nx = 0
    75  		}
    76  		p = p[n:]
    77  	}
    78  	n := _Block(d, p)
    79  	p = p[n:]
    80  	if len(p) > 0 {
    81  		d.nx = copy(d.x[:], p)
    82  	}
    83  	return
    84  }
    85  
    86  func (d0 *digest) Sum(in []byte) []byte {
    87  	// Make a copy of d0 so that caller can keep writing and summing.
    88  	d := *d0
    89  
    90  	// Padding.  Add a 1 bit and 0 bits until 56 bytes mod 64.
    91  	tc := d.tc
    92  	var tmp [64]byte
    93  	tmp[0] = 0x80
    94  	if tc%64 < 56 {
    95  		d.Write(tmp[0 : 56-tc%64])
    96  	} else {
    97  		d.Write(tmp[0 : 64+56-tc%64])
    98  	}
    99  
   100  	// Length in bits.
   101  	tc <<= 3
   102  	for i := uint(0); i < 8; i++ {
   103  		tmp[i] = byte(tc >> (8 * i))
   104  	}
   105  	d.Write(tmp[0:8])
   106  
   107  	if d.nx != 0 {
   108  		panic("d.nx != 0")
   109  	}
   110  
   111  	var digest [Size]byte
   112  	for i, s := range d.s {
   113  		digest[i*4] = byte(s)
   114  		digest[i*4+1] = byte(s >> 8)
   115  		digest[i*4+2] = byte(s >> 16)
   116  		digest[i*4+3] = byte(s >> 24)
   117  	}
   118  
   119  	return append(in, digest[:]...)
   120  }