| /** |
| * \brief HAVEGE: HArdware Volatile Entropy Gathering and Expansion |
| * |
| * Copyright (C) 2006-2010, Brainspark B.V. |
| * |
| * This file is part of PolarSSL (http://www.polarssl.org) |
| * Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org> |
| * |
| * All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License along |
| * with this program; if not, write to the Free Software Foundation, Inc., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| */ |
| /* |
| * The HAVEGE RNG was designed by Andre Seznec in 2002. |
| * |
| * http://www.irisa.fr/caps/projects/hipsor/publi.php |
| * |
| * Contact: seznec(at)irisa_dot_fr - orocheco(at)irisa_dot_fr |
| */ |
| |
| #include "polarssl/config.h" |
| |
| #if defined(POLARSSL_HAVEGE_C) |
| |
| #include "polarssl/havege.h" |
| #include "polarssl/timing.h" |
| |
| #include <string.h> |
| |
| /* ------------------------------------------------------------------------ |
| * On average, one iteration accesses two 8-word blocks in the havege WALK |
| * table, and generates 16 words in the RES array. |
| * |
| * The data read in the WALK table is updated and permuted after each use. |
| * The result of the hardware clock counter read is used for this update. |
| * |
| * 25 conditional tests are present. The conditional tests are grouped in |
| * two nested groups of 12 conditional tests and 1 test that controls the |
| * permutation; on average, there should be 6 tests executed and 3 of them |
| * should be mispredicted. |
| * ------------------------------------------------------------------------ |
| */ |
| |
| #define SWAP(X,Y) { int *T = X; X = Y; Y = T; } |
| |
| #define TST1_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1; |
| #define TST2_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1; |
| |
| #define TST1_LEAVE U1++; } |
| #define TST2_LEAVE U2++; } |
| |
| #define ONE_ITERATION \ |
| \ |
| PTEST = PT1 >> 20; \ |
| \ |
| TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \ |
| TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \ |
| TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \ |
| \ |
| TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \ |
| TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \ |
| TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \ |
| \ |
| PTX = (PT1 >> 18) & 7; \ |
| PT1 &= 0x1FFF; \ |
| PT2 &= 0x1FFF; \ |
| CLK = (int) hardclock(); \ |
| \ |
| i = 0; \ |
| A = &WALK[PT1 ]; RES[i++] ^= *A; \ |
| B = &WALK[PT2 ]; RES[i++] ^= *B; \ |
| C = &WALK[PT1 ^ 1]; RES[i++] ^= *C; \ |
| D = &WALK[PT2 ^ 4]; RES[i++] ^= *D; \ |
| \ |
| IN = (*A >> (1)) ^ (*A << (31)) ^ CLK; \ |
| *A = (*B >> (2)) ^ (*B << (30)) ^ CLK; \ |
| *B = IN ^ U1; \ |
| *C = (*C >> (3)) ^ (*C << (29)) ^ CLK; \ |
| *D = (*D >> (4)) ^ (*D << (28)) ^ CLK; \ |
| \ |
| A = &WALK[PT1 ^ 2]; RES[i++] ^= *A; \ |
| B = &WALK[PT2 ^ 2]; RES[i++] ^= *B; \ |
| C = &WALK[PT1 ^ 3]; RES[i++] ^= *C; \ |
| D = &WALK[PT2 ^ 6]; RES[i++] ^= *D; \ |
| \ |
| if( PTEST & 1 ) SWAP( A, C ); \ |
| \ |
| IN = (*A >> (5)) ^ (*A << (27)) ^ CLK; \ |
| *A = (*B >> (6)) ^ (*B << (26)) ^ CLK; \ |
| *B = IN; CLK = (int) hardclock(); \ |
| *C = (*C >> (7)) ^ (*C << (25)) ^ CLK; \ |
| *D = (*D >> (8)) ^ (*D << (24)) ^ CLK; \ |
| \ |
| A = &WALK[PT1 ^ 4]; \ |
| B = &WALK[PT2 ^ 1]; \ |
| \ |
| PTEST = PT2 >> 1; \ |
| \ |
| PT2 = (RES[(i - 8) ^ PTY] ^ WALK[PT2 ^ PTY ^ 7]); \ |
| PT2 = ((PT2 & 0x1FFF) & (~8)) ^ ((PT1 ^ 8) & 0x8); \ |
| PTY = (PT2 >> 10) & 7; \ |
| \ |
| TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \ |
| TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \ |
| TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \ |
| \ |
| TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \ |
| TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \ |
| TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \ |
| \ |
| C = &WALK[PT1 ^ 5]; \ |
| D = &WALK[PT2 ^ 5]; \ |
| \ |
| RES[i++] ^= *A; \ |
| RES[i++] ^= *B; \ |
| RES[i++] ^= *C; \ |
| RES[i++] ^= *D; \ |
| \ |
| IN = (*A >> ( 9)) ^ (*A << (23)) ^ CLK; \ |
| *A = (*B >> (10)) ^ (*B << (22)) ^ CLK; \ |
| *B = IN ^ U2; \ |
| *C = (*C >> (11)) ^ (*C << (21)) ^ CLK; \ |
| *D = (*D >> (12)) ^ (*D << (20)) ^ CLK; \ |
| \ |
| A = &WALK[PT1 ^ 6]; RES[i++] ^= *A; \ |
| B = &WALK[PT2 ^ 3]; RES[i++] ^= *B; \ |
| C = &WALK[PT1 ^ 7]; RES[i++] ^= *C; \ |
| D = &WALK[PT2 ^ 7]; RES[i++] ^= *D; \ |
| \ |
| IN = (*A >> (13)) ^ (*A << (19)) ^ CLK; \ |
| *A = (*B >> (14)) ^ (*B << (18)) ^ CLK; \ |
| *B = IN; \ |
| *C = (*C >> (15)) ^ (*C << (17)) ^ CLK; \ |
| *D = (*D >> (16)) ^ (*D << (16)) ^ CLK; \ |
| \ |
| PT1 = ( RES[(i - 8) ^ PTX] ^ \ |
| WALK[PT1 ^ PTX ^ 7] ) & (~1); \ |
| PT1 ^= (PT2 ^ 0x10) & 0x10; \ |
| \ |
| for( n++, i = 0; i < 16; i++ ) \ |
| hs->pool[n % COLLECT_SIZE] ^= RES[i]; |
| |
| /* |
| * Entropy gathering function |
| */ |
| static void havege_fill( havege_state *hs ) |
| { |
| int i, n = 0; |
| int U1, U2, *A, *B, *C, *D; |
| int PT1, PT2, *WALK, RES[16]; |
| int PTX, PTY, CLK, PTEST, IN; |
| |
| WALK = hs->WALK; |
| PT1 = hs->PT1; |
| PT2 = hs->PT2; |
| |
| PTX = U1 = 0; |
| PTY = U2 = 0; |
| |
| memset( RES, 0, sizeof( RES ) ); |
| |
| while( n < COLLECT_SIZE * 4 ) |
| { |
| ONE_ITERATION |
| ONE_ITERATION |
| ONE_ITERATION |
| ONE_ITERATION |
| } |
| |
| hs->PT1 = PT1; |
| hs->PT2 = PT2; |
| |
| hs->offset[0] = 0; |
| hs->offset[1] = COLLECT_SIZE / 2; |
| } |
| |
| /* |
| * HAVEGE initialization |
| */ |
| void havege_init( havege_state *hs ) |
| { |
| memset( hs, 0, sizeof( havege_state ) ); |
| |
| havege_fill( hs ); |
| } |
| |
| /* |
| * HAVEGE rand function |
| */ |
| int havege_random( void *p_rng, unsigned char *buf, size_t len ) |
| { |
| int val; |
| size_t use_len; |
| havege_state *hs = (havege_state *) p_rng; |
| unsigned char *p = buf; |
| |
| while( len > 0 ) |
| { |
| use_len = len; |
| if( use_len > sizeof(int) ) |
| use_len = sizeof(int); |
| |
| if( hs->offset[1] >= COLLECT_SIZE ) |
| havege_fill( hs ); |
| |
| val = hs->pool[hs->offset[0]++]; |
| val ^= hs->pool[hs->offset[1]++]; |
| |
| memcpy( p, &val, use_len ); |
| |
| len -= use_len; |
| p += use_len; |
| } |
| |
| return( 0 ); |
| } |
| |
| #endif |