BLAKE及BLAKE2算法详解

2019/04/10 10:10
阅读数 14

1 简介

哈希算法 (Hash Algorithm) 是将任意长度的数据映射为固定长度数据的算法,也称为消息摘要。
一般情况下,哈希算法有两个特点:

  1. 原始数据的细微变化(比如一个位翻转)会导致结果产生巨大差距
  2. 运算过程不可逆,理论上无法从结果还原输入数据

因此,哈希算法主要用于数据完整性校验和加密/签名。而哈希算法的安全性就在于碰撞难易度,即已知结果,构建出具有相同结果的输入数据的难易度。

2 BLAKE

BLAKE算法于2008年提出,它包含两个版本,一种基于32位word用于产生最长256位的哈希结果,一种基于64位word用于产生最长512位的哈希结果,BLAKE算法核心操作是不断地将8个散列中间结果和16个输入word进行组合,从而产生下一轮组合的8个中间结果。按照最终截断的哈希长度,BLAKE-256和BLAKE-224使用32位字分别产生256位和224位的哈希结果(也称消息摘要),而BLAKE-512和BLAKE-384使用64位字并产生512位和384位哈希结果。算法核心变量如下:

 1 typedef struct
 2 {
 3   uint32_t h[8], s[4], t[2];
 4   int buflen, nullt;
 5   uint8_t  buf[64];
 6 } state256;
 7 
 8 typedef state256 state224;
 9 
10 typedef struct
11 {
12   uint64_t h[8], s[4], t[2];
13   int buflen, nullt;
14   uint8_t buf[128];
15 } state512;
16 
17 typedef state512 state384;
18 
19 const uint8_t sigma[][16] =
20 {
21   { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
22   {14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3 },
23   {11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4 },
24   { 7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8 },
25   { 9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13 },
26   { 2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9 },
27   {12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11 },
28   {13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10 },
29   { 6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5 },
30   {10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13 , 0 },
31   { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
32   {14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3 },
33   {11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4 },
34   { 7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8 },
35   { 9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13 },
36   { 2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9 }
37 };
38 
39 const uint32_t u256[16] =
40 {
41   0x243f6a88, 0x85a308d3, 0x13198a2e, 0x03707344,
42   0xa4093822, 0x299f31d0, 0x082efa98, 0xec4e6c89,
43   0x452821e6, 0x38d01377, 0xbe5466cf, 0x34e90c6c,
44   0xc0ac29b7, 0xc97c50dd, 0x3f84d5b5, 0xb5470917
45 };
46 
47 const uint64_t u512[16] =
48 {
49   0x243f6a8885a308d3ULL, 0x13198a2e03707344ULL, 
50   0xa4093822299f31d0ULL, 0x082efa98ec4e6c89ULL,
51   0x452821e638d01377ULL, 0xbe5466cf34e90c6cULL, 
52   0xc0ac29b7c97c50ddULL, 0x3f84d5b5b5470917ULL,
53   0x9216d5d98979fb1bULL, 0xd1310ba698dfb5acULL, 
54   0x2ffd72dbd01adfb7ULL, 0xb8e1afed6a267e96ULL,
55   0xba7c9045f12c7f99ULL, 0x24a19947b3916cf7ULL, 
56   0x0801f2e2858efc16ULL, 0x636920d871574e69ULL
57 };
58 
59 
60 static const uint8_t padding[129] =
61 {
62   0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
63   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
64   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
65   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
66   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
67   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
68   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
69   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
70 };
blake

blake256核心计算过程如下:

 1 void blake256_compress( state256 *S, const uint8_t *block )
 2 {
 3   uint32_t v[16], m[16], i;
 4 #define ROT(x,n) (((x)<<(32-n))|( (x)>>(n)))
 5 #define G(a,b,c,d,e)          \
 6   v[a] += (m[sigma[i][e]] ^ u256[sigma[i][e+1]]) + v[b]; \
 7   v[d] = ROT( v[d] ^ v[a],16);        \
 8   v[c] += v[d];           \
 9   v[b] = ROT( v[b] ^ v[c],12);        \
10   v[a] += (m[sigma[i][e+1]] ^ u256[sigma[i][e]])+v[b]; \
11   v[d] = ROT( v[d] ^ v[a], 8);        \
12   v[c] += v[d];           \
13   v[b] = ROT( v[b] ^ v[c], 7);
14 
15   for( i = 0; i < 16; ++i )  m[i] = U8TO32_BIG( block + i * 4 );
16 
17   for( i = 0; i < 8; ++i )  v[i] = S->h[i];
18 
19   v[ 8] = S->s[0] ^ u256[0];
20   v[ 9] = S->s[1] ^ u256[1];
21   v[10] = S->s[2] ^ u256[2];
22   v[11] = S->s[3] ^ u256[3];
23   v[12] = u256[4];
24   v[13] = u256[5];
25   v[14] = u256[6];
26   v[15] = u256[7];
27 
28   /* don't xor t when the block is only padding */
29   if ( !S->nullt )
30   {
31     v[12] ^= S->t[0];
32     v[13] ^= S->t[0];
33     v[14] ^= S->t[1];
34     v[15] ^= S->t[1];
35   }
36 
37   for( i = 0; i < 14; ++i )
38   {
39     /* column step */
40     G( 0,  4,  8, 12,  0 );
41     G( 1,  5,  9, 13,  2 );
42     G( 2,  6, 10, 14,  4 );
43     G( 3,  7, 11, 15,  6 );
44     /* diagonal step */
45     G( 0,  5, 10, 15,  8 );
46     G( 1,  6, 11, 12, 10 );
47     G( 2,  7,  8, 13, 12 );
48     G( 3,  4,  9, 14, 14 );
49   }
50 
51   for( i = 0; i < 16; ++i )  S->h[i % 8] ^= v[i];
52 
53   for( i = 0; i < 8 ; ++i )  S->h[i] ^= S->s[i % 4];
54 }
blake256_compress

详细实现可参考网上开源代码,BLAKE源码:https://github.com/veorq/BLAKE
四种算法对空字符串的哈希结果如下:

BLAKE-224("") =
7dc5313b1c04512a174bd6503b89607aecbee0903d40a8a569c94eed
BLAKE-256("") =
716f6e863f744b9ac22c97ec7b76ea5f5908bc5b2f67c61510bfc4751384ea7a
BLAKE-384("") =
c6cbd89c926ab525c242e6621f2f5fa73aa4afe3d9e24aed727faaadd6af38b620bdb623dd2b4788b1c8086984af8706
BLAKE-512("") =
a8cfbbd73726062df0c6864dda65defe58ef0cc52a5625090fa17601e1eecd1b628e94f396ae402a00acc9eab77b4d4c2e852aaaa25a636d80af3fc7913ef5b8

 3 BLAKE2

BLAKE2算法基于BLAKE算法,于2012年被提出,BLAKE2不再向blake round函数中对输入字添加常量,修改了两个旋转常量及padding等,并在BLAKE2b(对应BLAKE-512)中将rounds的数量由16减少为12,在BLAKE2s(对应BLAKE-256)中将rounds数量由14减少为10,同样的,BLAKE2b产生1到64字节的消息摘要,BLAKE2s产生1到32字节的消息摘要,同时这两种算法也由对应的多核并行版本BLAKE2bp(4路并行)和BLAKE2sp(8路并行)。除了以上几种算法变种,BLAKE2还有一种BLAKE2x的变种,这种算法可以产生任意长度的消息摘要,详情请参考相应文档。除了安全性方面的优势,据称BLAKE2算法在Intel CPU第六代微处理架构(Skylake)中的处理速度要优于MD5,SHA-1,SHA-2和SHA-3等算法,如图所示:

BLAKE2源码可以参考:https://github.com/BLAKE2/BLAKE2,类似的,BLAKE2对空字符串的哈希结果如下:

BLAKE2s-224("") =
1fa1291e65248b37b3433475b2a0dd63d54a11ecc4e3e034e7bc1ef4
BLAKE2s-256("") =
69217a3079908094e11121d042354a7c1f55b6482ca1a51e1b250dfd1ed0eef9
BLAKE2b-384("") =
b32811423377f52d7862286ee1a72ee540524380fda1724a6f25d7978c6fd3244a6caf0498812673c5e05ef583825100
BLAKE2b-512("") =
786a02f742015903c6c6fd852552d272912f4740e15847618a86e217f71f5419d25e1031afee585313896444934eb04b903a685b1448b755d56f701afe9be2ce

 4 应用

BLAKE系列算法被广泛应用于区块链数字货币领域,下面介绍3中典型数字货币:

1 decred
以blake256为核心哈希算法,其主页为:https://decred.org/

2 sia
以blake2b为核心哈希算法,其主页为:https://sia.tech/

3 verge
以blake2s为核心哈希算法,其主页为:https://vergecurrency.com/

至于具体哈希算法在各个币种应用细节,请参考相关钱包的源代码。

参考:

https://en.wikipedia.org/wiki/BLAKE_(hash_function)

2 Blake web site

3 Blake2 web site

https://coinguides.org/

原文出处:https://www.cnblogs.com/zhaoweiwei/p/blake.html

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