Rework ecp_mod_p192()
On x86_64, this makes it 5x faster, and ecp_mul() 17% faster for this curve. The code is shorter too.
This commit is contained in:
Manuel Pégourié-Gonnard
parent
6888167e73
commit
d1e7a45fdd
101
library/ecp.c
101
library/ecp.c
@ -475,25 +475,36 @@ cleanup:
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}
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#if defined(POLARSSL_ECP_DP_SECP192R1_ENABLED)
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/*
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* 192 bits in terms of t_uint
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*/
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#define P192_SIZE_INT ( 192 / CHAR_BIT / sizeof( t_uint ) )
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/*
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* Table to get S1, S2, S3 of FIPS 186-3 D.2.1:
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* -1 means let this chunk be 0
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* a positive value i means A_i.
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*/
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#define P192_CHUNKS 3
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#define P192_CHUNK_CHAR ( 64 / CHAR_BIT )
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#define P192_CHUNK_INT ( P192_CHUNK_CHAR / sizeof( t_uint ) )
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/* Add 64-bit chunks (dst += src) and update carry */
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static inline void add_64( t_uint *dst, t_uint *src, t_uint *carry )
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{
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unsigned char i;
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t_uint c = 0;
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for( i = 0; i < 8 / sizeof( t_uint ); i++, dst++, src++ )
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{
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*dst += c; c = ( *dst < c );
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*dst += *src; c += ( *dst < *src );
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}
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*carry += c;
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}
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const signed char p192_tbl[][P192_CHUNKS] = {
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{ -1, 3, 3 }, /* S1 */
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{ 4, 4, -1 }, /* S2 */
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{ 5, 5, 5 }, /* S3 */
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};
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/* Add carry to a 64-bit chunk and update carry */
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static inline void carry64( t_uint *dst, t_uint *carry )
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{
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unsigned char i;
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for( i = 0; i < 8 / sizeof( t_uint ); i++, dst++ )
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{
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*dst += *carry;
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*carry = ( *dst < *carry );
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}
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}
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#define OFFSET ( 8 / sizeof( t_uint ) )
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#define A( i ) ( N->p + ( i ) * OFFSET )
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#define ADD( i ) add_64( p, A( i ), &c )
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#define NEXT p += OFFSET; carry64( p, &c )
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#define LAST p += OFFSET; *p = c; while( ++p < end ) *p = 0
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/*
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* Fast quasi-reduction modulo p192 (FIPS 186-3 D.2.1)
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@ -501,53 +512,27 @@ const signed char p192_tbl[][P192_CHUNKS] = {
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static int ecp_mod_p192( mpi *N )
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{
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int ret;
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unsigned char i, j, offset;
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signed char chunk;
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mpi tmp, acc;
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t_uint tmp_p[P192_SIZE_INT], acc_p[P192_SIZE_INT + 1];
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t_uint c = 0;
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t_uint *p, *end;
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tmp.s = 1;
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tmp.n = sizeof( tmp_p ) / sizeof( tmp_p[0] );
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tmp.p = tmp_p;
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/* Make sure we have the correct number of blocks */
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MPI_CHK( mpi_grow( N, 6 * OFFSET ) );
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p = N->p;
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end = p + N->n;
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acc.s = 1;
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acc.n = sizeof( acc_p ) / sizeof( acc_p[0] );
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acc.p = acc_p;
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MPI_CHK( mpi_grow( N, P192_SIZE_INT * 2 ) );
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/*
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* acc = T
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*/
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memset( acc_p, 0, sizeof( acc_p ) );
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memcpy( acc_p, N->p, P192_CHUNK_CHAR * P192_CHUNKS );
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for( i = 0; i < sizeof( p192_tbl ) / sizeof( p192_tbl[0] ); i++)
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{
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/*
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* tmp = S_i
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*/
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memset( tmp_p, 0, sizeof( tmp_p ) );
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for( j = 0, offset = P192_CHUNKS - 1; j < P192_CHUNKS; j++, offset-- )
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{
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chunk = p192_tbl[i][j];
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if( chunk >= 0 )
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memcpy( tmp_p + offset * P192_CHUNK_INT,
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N->p + chunk * P192_CHUNK_INT,
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P192_CHUNK_CHAR );
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}
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/*
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* acc += tmp
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*/
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MPI_CHK( mpi_add_abs( &acc, &acc, &tmp ) );
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}
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MPI_CHK( mpi_copy( N, &acc ) );
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ADD( 3 ); ADD( 5 ); NEXT; // A0 += A3 + A5
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ADD( 3 ); ADD( 4 ); ADD( 5 ); NEXT; // A1 += A3 + A4 + A5
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ADD( 4 ); ADD( 5 ); LAST; // A2 += A4 + A5
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cleanup:
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return( ret );
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}
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#undef OFFSET
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#undef A
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#undef ADD
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#undef NEXT
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#undef LAST
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#endif /* POLARSSL_ECP_DP_SECP192R1_ENABLED */
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#if defined(POLARSSL_ECP_DP_SECP521R1_ENABLED)
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@ -253,14 +253,26 @@ ECP gen keypair
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depends_on:POLARSSL_ECP_DP_SECP192R1_ENABLED
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ecp_gen_keypair:POLARSSL_ECP_DP_SECP192R1
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ECP mod p192 small (more than 192 bits, less limbs than 2 * 192 bits)
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depends_on:POLARSSL_ECP_DP_SECP192R1_ENABLED
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ecp_fast_mod:POLARSSL_ECP_DP_SECP192R1:"0100000000000103010000000000010201000000000001010100000000000100"
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ECP mod p192 readable
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depends_on:POLARSSL_ECP_DP_SECP192R1_ENABLED
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ecp_fast_mod:POLARSSL_ECP_DP_SECP192R1:"000000000000010500000000000001040000000000000103000000000000010200000000000001010000000000000100"
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ecp_fast_mod:POLARSSL_ECP_DP_SECP192R1:"010000000000010501000000000001040100000000000103010000000000010201000000000001010100000000000100"
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ECP mod p192 readable with carry
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depends_on:POLARSSL_ECP_DP_SECP192R1_ENABLED
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ecp_fast_mod:POLARSSL_ECP_DP_SECP192R1:"FF00000000010500FF00000000010400FF00000000010300FF00000000010200FF00000000010100FF00000000010000"
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ECP mod p192 random
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depends_on:POLARSSL_ECP_DP_SECP192R1_ENABLED
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ecp_fast_mod:POLARSSL_ECP_DP_SECP192R1:"36CF96B45D706A0954D89E52CE5F38517A2270E0175849B6F3740151D238CCABEF921437E475881D83BB69E4AA258EBD"
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ECP mod p192 (from a past failure case)
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depends_on:POLARSSL_ECP_DP_SECP192R1_ENABLED
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ecp_fast_mod:POLARSSL_ECP_DP_SECP192R1:"1AC2D6F96A2A425E9DD1776DD8368D4BBC86BF4964E79FEA713583BF948BBEFF0939F96FB19EC48C585BDA6A2D35C750"
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ECP test vectors secp192r1 rfc 5114
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depends_on:POLARSSL_ECP_DP_SECP192R1_ENABLED
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ecp_test_vect:POLARSSL_ECP_DP_SECP192R1:"323FA3169D8E9C6593F59476BC142000AB5BE0E249C43426":"CD46489ECFD6C105E7B3D32566E2B122E249ABAADD870612":"68887B4877DF51DD4DC3D6FD11F0A26F8FD3844317916E9A":"631F95BB4A67632C9C476EEE9AB695AB240A0499307FCF62":"519A121680E0045466BA21DF2EEE47F5973B500577EF13D5":"FF613AB4D64CEE3A20875BDB10F953F6B30CA072C60AA57F":"AD420182633F8526BFE954ACDA376F05E5FF4F837F54FEBE":"4371545ED772A59741D0EDA32C671112B7FDDD51461FCF32"
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