1 /*
2 SipHash reference C implementation
3
4 Copyright (c) 2012-2016 Jean-Philippe Aumasson
5 <jeanphilippe.aumasson@gmail.com>
6 Copyright (c) 2012-2014 Daniel J. Bernstein <djb@cr.yp.to>
7
8 To the extent possible under law, the author(s) have dedicated all copyright
9 and related and neighboring rights to this software to the public domain
10 worldwide. This software is distributed without any warranty.
11
12 You should have received a copy of the CC0 Public Domain Dedication along
13 with
14 this software. If not, see
15 <http://creativecommons.org/publicdomain/zero/1.0/>.
16 */
17 #include <assert.h>
18 #include <stdint.h>
19 #include <stdio.h>
20 #include <string.h>
21
22 /* default: SipHash-2-4 */
23 #define cROUNDS 2
24 #define dROUNDS 4
25
26 #define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
27
28 #define U32TO8_LE(p, v) \
29 (p)[0] = (uint8_t)((v)); \
30 (p)[1] = (uint8_t)((v) >> 8); \
31 (p)[2] = (uint8_t)((v) >> 16); \
32 (p)[3] = (uint8_t)((v) >> 24);
33
34 #define U64TO8_LE(p, v) \
35 U32TO8_LE((p), (uint32_t)((v))); \
36 U32TO8_LE((p) + 4, (uint32_t)((v) >> 32));
37
38 #define U8TO64_LE(p) \
39 (((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) | \
40 ((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) | \
41 ((uint64_t)((p)[4]) << 32) | ((uint64_t)((p)[5]) << 40) | \
42 ((uint64_t)((p)[6]) << 48) | ((uint64_t)((p)[7]) << 56))
43
44 #define SIPROUND \
45 do { \
46 v0 += v1; \
47 v1 = ROTL(v1, 13); \
48 v1 ^= v0; \
49 v0 = ROTL(v0, 32); \
50 v2 += v3; \
51 v3 = ROTL(v3, 16); \
52 v3 ^= v2; \
53 v0 += v3; \
54 v3 = ROTL(v3, 21); \
55 v3 ^= v0; \
56 v2 += v1; \
57 v1 = ROTL(v1, 17); \
58 v1 ^= v2; \
59 v2 = ROTL(v2, 32); \
60 } while (0)
61
62 #ifdef DEBUG
63 #define TRACE \
64 do { \
65 printf("(%3d) v0 %08x %08x\n", (int)inlen, (uint32_t)(v0 >> 32), \
66 (uint32_t)v0); \
67 printf("(%3d) v1 %08x %08x\n", (int)inlen, (uint32_t)(v1 >> 32), \
68 (uint32_t)v1); \
69 printf("(%3d) v2 %08x %08x\n", (int)inlen, (uint32_t)(v2 >> 32), \
70 (uint32_t)v2); \
71 printf("(%3d) v3 %08x %08x\n", (int)inlen, (uint32_t)(v3 >> 32), \
72 (uint32_t)v3); \
73 } while (0)
74 #else
75 #define TRACE
76 #endif
77
siphash(const uint8_t * in,const size_t inlen,const uint8_t * k,uint8_t * out,const size_t outlen)78 int siphash(const uint8_t *in, const size_t inlen, const uint8_t *k,
79 uint8_t *out, const size_t outlen) {
80 uint64_t v0 = 0x736f6d6570736575ULL;
81 uint64_t v1 = 0x646f72616e646f6dULL;
82 uint64_t v2 = 0x6c7967656e657261ULL;
83 uint64_t v3 = 0x7465646279746573ULL;
84 uint64_t k0 = U8TO64_LE(k);
85 uint64_t k1 = U8TO64_LE(k + 8);
86 uint64_t m;
87 int i;
88 const uint8_t *end = in + inlen - (inlen % sizeof(uint64_t));
89 const int left = inlen & 7;
90 uint64_t b = ((uint64_t)inlen) << 56;
91 v3 ^= k1;
92 v2 ^= k0;
93 v1 ^= k1;
94 v0 ^= k0;
95
96 assert((outlen == 8) || (outlen == 16));
97 if (outlen == 16)
98 v1 ^= 0xee;
99
100 for (; in != end; in += 8) {
101 m = U8TO64_LE(in);
102 v3 ^= m;
103
104 TRACE;
105 for (i = 0; i < cROUNDS; ++i)
106 SIPROUND;
107
108 v0 ^= m;
109 }
110
111 switch (left) {
112 case 7:
113 b |= ((uint64_t)in[6]) << 48;
114 /* fallthrough */
115 case 6:
116 b |= ((uint64_t)in[5]) << 40;
117 /* fallthrough */
118 case 5:
119 b |= ((uint64_t)in[4]) << 32;
120 /* fallthrough */
121 case 4:
122 b |= ((uint64_t)in[3]) << 24;
123 /* fallthrough */
124 case 3:
125 b |= ((uint64_t)in[2]) << 16;
126 /* fallthrough */
127 case 2:
128 b |= ((uint64_t)in[1]) << 8;
129 /* fallthrough */
130 case 1:
131 b |= ((uint64_t)in[0]);
132 break;
133 case 0:
134 break;
135 }
136
137 v3 ^= b;
138
139 TRACE;
140 for (i = 0; i < cROUNDS; ++i)
141 SIPROUND;
142
143 v0 ^= b;
144
145 if (outlen == 16)
146 v2 ^= 0xee;
147 else
148 v2 ^= 0xff;
149
150 TRACE;
151 for (i = 0; i < dROUNDS; ++i)
152 SIPROUND;
153
154 b = v0 ^ v1 ^ v2 ^ v3;
155 U64TO8_LE(out, b);
156
157 if (outlen == 8)
158 return 0;
159
160 v1 ^= 0xdd;
161
162 TRACE;
163 for (i = 0; i < dROUNDS; ++i)
164 SIPROUND;
165
166 b = v0 ^ v1 ^ v2 ^ v3;
167 U64TO8_LE(out + 8, b);
168
169 return 0;
170 }
171