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/* This is SipHash by Jean-Philippe Aumasson and Daniel J. Bernstein.
* The authors claim it is relatively secure compared to the alternatives
* and that performance wise it is a suitable hash for languages like Perl.
* See:
*
* https://www.131002.net/siphash/
*
* Naming convention:
*
* S_perl_hash_siphash_N_M: the N refers to how many rounds are performed per
* block. The M refers to how many rounds are performed as part of the
* finalizer. Increased values of either improve security, but decrease
* performance.
*
* _with_state: these functions take a 32 bit state vector prepared by
* S_perl_siphash_seed_state(). Functions without 'with_state' take a 16
* byte seed vector and call S_perl_siphash_seed_state() implicitly. If
* you are hashing many things with the same seed, the _with_state
* variants are faster.
*
* _64: returns a 64 bit hash
*
* no-suffix: returns a 32 bit hash.
*
* This file defines 9 functions related to implementing 2 variants of
* the Siphash family of hash functions, Siphash-2-4, and Siphash-1-3.
=for apidoc_section $numeric
=for apidoc eST|void|S_perl_siphash_seed_state \
|const unsigned char * const seed_buf \
|unsigned char * state_buf
Takes a 16 byte seed and converts it into a 32 byte state buffer. The
contents of state_buf will be overwritten.
If you need to hash a lot of things, then you can use this to process
the seed once, and then reuse the state over and over.
The siphash functions which take a seed argument will call this function
implicitly every time they are used. Those which take a state argument
require the seed to be converted into a state before they are used.
See the various _with_state siphash functions for a usage example.
=for apidoc eSTP|U64|S_perl_hash_siphash_1_3_with_state_64\
|const unsigned char * const state \
|const unsigned char *in|const STRLEN inlen
Implements the variant of Siphash which performs 1 round function
per block, and 3 as part of the finalizer.
Takes a 32 byte 'state' vector prepared by S_perl_siphash_seed_state()
and uses it to hash C<inlen> bytes from the buffer pointed to by C<in>,
returns a 64 bit hash.
The following code should return 0xB70339FD9E758A5C
U8 state[32];
char seed[] = "Call me Ishmael.";
S_perl_siphash_seed_state((const U8*)seed, state);
char in[] = "It is not down on any map; true places never are.";
U64 hash = S_perl_hash_siphash_1_3_with_state_64(
state, (const U8*)in, sizeof(in)-1);
=for apidoc eSTP|U32|S_perl_hash_siphash_1_3_with_state\
|const unsigned char * const state \
|const unsigned char *in|const STRLEN inlen
Implements the variant of Siphash which performs 1 round function
per block, and 3 as part of the finalizer.
Takes a 32 byte 'state' vector prepared by S_perl_siphash_seed_state()
and uses it to hash C<inlen> bytes from the buffer pointed to by C<in>,
returns a 32 bit hash.
The following code should return 0x2976B3A1
U8 state[32];
char seed[] = "Call me Ishmael.";
S_perl_siphash_seed_state((const U8*)seed, state);
char in[] = "It is not down on any map; true places never are.";
U32 hash = S_perl_hash_siphash_1_3_with_state(
state, (const U8*)in, sizeof(in)-1);
=for apidoc eSTP|U64|S_perl_hash_siphash_1_3_64\
|const unsigned char * const seed \
|const unsigned char *in|const STRLEN inlen
Implements the variant of Siphash which performs 1 round function
per block, and 3 as part of the finalizer.
Takes a 16 byte C<seed> vector, and uses it to hash C<inlen> bytes
from the buffer pointed to by C<in>, returns a 64 bit hash.
The following code should return 0xB70339FD9E758A5C
char seed[] = "Call me Ishmael.";
char in[] = "It is not down on any map; true places never are.";
U64 hash = S_perl_hash_siphash_1_3_64(
(const U8*)seed, (const U8*)in, sizeof(in)-1);
=for apidoc eSTP|U64|S_perl_hash_siphash_1_3\
|const unsigned char * const seed \
|const unsigned char *in|const STRLEN inlen
Implements the variant of Siphash which performs 1 round function
per block, and 3 as part of the finalizer.
Takes a 16 byte C<seed> vector, and uses it to hash C<inlen> bytes
from the buffer pointed to by C<in>, returns a 32 bit hash.
The following code should return 0x2976B3A1
char seed[] = "Call me Ishmael.";
char in[] = "It is not down on any map; true places never are.";
U32 hash = S_perl_hash_siphash_1_3(
(const U8*)seed, (const U8*)in, sizeof(in)-1);
=for apidoc eSTP|U64|S_perl_hash_siphash_2_4_with_state_64\
|const unsigned char * const state \
|const unsigned char *in|const STRLEN inlen
Implements the variant of Siphash which performs 2 round functions
per block, and 4 as part of the finalizer.
Takes a 32 byte 'state' vector prepared by S_perl_siphash_seed_state()
and uses it to hash C<inlen> bytes from the buffer pointed to by C<in>,
returns a 64 bit hash.
The following code should return 0x1E84CF1D7AA516B7
U8 state[32];
char seed[] = "Call me Ishmael.";
S_perl_siphash_seed_state((const U8*)seed, state);
char in[] = "It is not down on any map; true places never are.";
U64 hash = S_perl_hash_siphash_2_4_with_state_64(
state, (const U8*)in, sizeof(in)-1);
=for apidoc eSTP|U32|S_perl_hash_siphash_2_4_with_state\
|const unsigned char * const state \
|const unsigned char *in|const STRLEN inlen
Implements the variant of Siphash which performs 2 round function
per block, and 4 as part of the finalizer.
Takes a 32 byte 'state' vector prepared by S_perl_siphash_seed_state()
and uses it to hash C<inlen> bytes from the buffer pointed to by C<in>,
returns a 32 bit hash.
The following code should return 0x6421D9AA
U8 state[32];
char seed[] = "Call me Ishmael.";
S_perl_siphash_seed_state((const U8*)seed, state);
char in[] = "It is not down on any map; true places never are.";
U32 hash = S_perl_hash_siphash_2_4_with_state(
state, (const U8*)in, sizeof(in)-1);
=for apidoc eSTP|U64|S_perl_hash_siphash_2_4_64\
|const unsigned char * const seed \
|const unsigned char *in|const STRLEN inlen
Implements the variant of Siphash which performs 2 round functions
per block, and 4 as part of the finalizer.
Takes a 16 byte C<seed> vector, and uses it to hash C<inlen> bytes
from the buffer pointed to by C<in>, returns a 64 bit hash.
The following code should return 0x1E84CF1D7AA516B7
char seed[] = "Call me Ishmael.";
char in[] = "It is not down on any map; true places never are.";
U64 hash = S_perl_hash_siphash_2_4_64(
(const U8*)seed, (const U8*)in, sizeof(in)-1);
=for apidoc eSTP|U32|S_perl_hash_siphash_2_4\
|const unsigned char * const seed \
|const unsigned char *in|const STRLEN inlen
Implements the variant of Siphash which performs 2 round functions
per block, and 4 as part of the finalizer.
Takes a 16 byte C<seed> vector, and uses it to hash C<inlen> bytes
from the buffer pointed to by C<in>, returns a 32 bit hash.
The following code should return 0x6421D9AA
char seed[] = "Call me Ishmael.";
char in[] = "It is not down on any map; true places never are.";
U32 hash = S_perl_hash_siphash_2_4(
(const U8*)seed, (const U8*)in, sizeof(in)-1);
=cut
*/
#ifdef CAN64BITHASH
#define SIPROUND \
STMT_START { \
v0 += v1; v1=ROTL64(v1,13); v1 ^= v0; v0=ROTL64(v0,32); \
v2 += v3; v3=ROTL64(v3,16); v3 ^= v2; \
v0 += v3; v3=ROTL64(v3,21); v3 ^= v0; \
v2 += v1; v1=ROTL64(v1,17); v1 ^= v2; v2=ROTL64(v2,32); \
} STMT_END
#define SIPHASH_SEED_STATE(key,v0,v1,v2,v3) \
do { \
v0 = v2 = U8TO64_LE(key + 0); \
v1 = v3 = U8TO64_LE(key + 8); \
/* "somepseudorandomlygeneratedbytes" */ \
v0 ^= UINT64_C(0x736f6d6570736575); \
v1 ^= UINT64_C(0x646f72616e646f6d); \
v2 ^= UINT64_C(0x6c7967656e657261); \
v3 ^= UINT64_C(0x7465646279746573); \
} while (0)
PERL_STATIC_INLINE
void S_perl_siphash_seed_state(const unsigned char * const seed_buf, unsigned char * state_buf) {
U64 *v= (U64*) state_buf;
SIPHASH_SEED_STATE(seed_buf, v[0],v[1],v[2],v[3]);
}
#define PERL_SIPHASH_FNC(FNC,SIP_ROUNDS,SIP_FINAL_ROUNDS) \
PERL_STATIC_INLINE U64 \
FNC ## _with_state_64 \
(const unsigned char * const state, const unsigned char *in, const STRLEN inlen) \
{ \
const int left = inlen & 7; \
const U8 *end = in + inlen - left;\
\
U64 b = ( ( U64 )(inlen) ) << 56; \
U64 m; \
U64 v0 = U8TO64_LE(state); \
U64 v1 = U8TO64_LE(state+8); \
U64 v2 = U8TO64_LE(state+16); \
U64 v3 = U8TO64_LE(state+24); \
\
for ( ; in != end; in += 8 ) \
{ \
m = U8TO64_LE( in ); \
v3 ^= m; \
\
SIP_ROUNDS; \
\
v0 ^= m; \
} \
\
switch( left ) \
{ \
case 7: b |= ( ( U64 )in[ 6] ) << 48; /*FALLTHROUGH*/ \
case 6: b |= ( ( U64 )in[ 5] ) << 40; /*FALLTHROUGH*/ \
case 5: b |= ( ( U64 )in[ 4] ) << 32; /*FALLTHROUGH*/ \
case 4: b |= ( ( U64 )in[ 3] ) << 24; /*FALLTHROUGH*/ \
case 3: b |= ( ( U64 )in[ 2] ) << 16; /*FALLTHROUGH*/ \
case 2: b |= ( ( U64 )in[ 1] ) << 8; /*FALLTHROUGH*/ \
case 1: b |= ( ( U64 )in[ 0] ); break; \
case 0: break; \
} \
\
v3 ^= b; \
\
SIP_ROUNDS; \
\
v0 ^= b; \
\
v2 ^= 0xff; \
\
SIP_FINAL_ROUNDS \
\
b = v0 ^ v1 ^ v2 ^ v3; \
return b; \
} \
\
PERL_STATIC_INLINE U32 \
FNC ## _with_state \
(const unsigned char * const state, const unsigned char *in, const STRLEN inlen) \
{ \
union { \
U64 h64; \
U32 h32[2]; \
} h; \
h.h64= FNC ## _with_state_64(state,in,inlen); \
return h.h32[0] ^ h.h32[1]; \
} \
\
\
PERL_STATIC_INLINE U32 \
FNC (const unsigned char * const seed, const unsigned char *in, const STRLEN inlen) \
{ \
U64 state[4]; \
SIPHASH_SEED_STATE(seed,state[0],state[1],state[2],state[3]); \
return FNC ## _with_state((U8*)state,in,inlen); \
} \
\
PERL_STATIC_INLINE U64 \
FNC ## _64 (const unsigned char * const seed, const unsigned char *in, const STRLEN inlen) \
{ \
U64 state[4]; \
SIPHASH_SEED_STATE(seed,state[0],state[1],state[2],state[3]); \
return FNC ## _with_state_64((U8*)state,in,inlen); \
}
PERL_SIPHASH_FNC(
S_perl_hash_siphash_1_3
,SIPROUND;
,SIPROUND;SIPROUND;SIPROUND;
)
PERL_SIPHASH_FNC(
S_perl_hash_siphash_2_4
,SIPROUND;SIPROUND;
,SIPROUND;SIPROUND;SIPROUND;SIPROUND;
)
#endif /* defined(CAN64BITHASH) */
|
