PolarSSL v1.1.4
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00001 00025 /* 00026 * The HAVEGE RNG was designed by Andre Seznec in 2002. 00027 * 00028 * http://www.irisa.fr/caps/projects/hipsor/publi.php 00029 * 00030 * Contact: seznec(at)irisa_dot_fr - orocheco(at)irisa_dot_fr 00031 */ 00032 00033 #include "polarssl/config.h" 00034 00035 #if defined(POLARSSL_HAVEGE_C) 00036 00037 #include "polarssl/havege.h" 00038 #include "polarssl/timing.h" 00039 00040 #include <string.h> 00041 #include <time.h> 00042 00043 /* ------------------------------------------------------------------------ 00044 * On average, one iteration accesses two 8-word blocks in the havege WALK 00045 * table, and generates 16 words in the RES array. 00046 * 00047 * The data read in the WALK table is updated and permuted after each use. 00048 * The result of the hardware clock counter read is used for this update. 00049 * 00050 * 25 conditional tests are present. The conditional tests are grouped in 00051 * two nested groups of 12 conditional tests and 1 test that controls the 00052 * permutation; on average, there should be 6 tests executed and 3 of them 00053 * should be mispredicted. 00054 * ------------------------------------------------------------------------ 00055 */ 00056 00057 #define SWAP(X,Y) { int *T = X; X = Y; Y = T; } 00058 00059 #define TST1_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1; 00060 #define TST2_ENTER if( PTEST & 1 ) { PTEST ^= 3; PTEST >>= 1; 00061 00062 #define TST1_LEAVE U1++; } 00063 #define TST2_LEAVE U2++; } 00064 00065 #define ONE_ITERATION \ 00066 \ 00067 PTEST = PT1 >> 20; \ 00068 \ 00069 TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \ 00070 TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \ 00071 TST1_ENTER TST1_ENTER TST1_ENTER TST1_ENTER \ 00072 \ 00073 TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \ 00074 TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \ 00075 TST1_LEAVE TST1_LEAVE TST1_LEAVE TST1_LEAVE \ 00076 \ 00077 PTX = (PT1 >> 18) & 7; \ 00078 PT1 &= 0x1FFF; \ 00079 PT2 &= 0x1FFF; \ 00080 CLK = (int) hardclock(); \ 00081 \ 00082 i = 0; \ 00083 A = &WALK[PT1 ]; RES[i++] ^= *A; \ 00084 B = &WALK[PT2 ]; RES[i++] ^= *B; \ 00085 C = &WALK[PT1 ^ 1]; RES[i++] ^= *C; \ 00086 D = &WALK[PT2 ^ 4]; RES[i++] ^= *D; \ 00087 \ 00088 IN = (*A >> (1)) ^ (*A << (31)) ^ CLK; \ 00089 *A = (*B >> (2)) ^ (*B << (30)) ^ CLK; \ 00090 *B = IN ^ U1; \ 00091 *C = (*C >> (3)) ^ (*C << (29)) ^ CLK; \ 00092 *D = (*D >> (4)) ^ (*D << (28)) ^ CLK; \ 00093 \ 00094 A = &WALK[PT1 ^ 2]; RES[i++] ^= *A; \ 00095 B = &WALK[PT2 ^ 2]; RES[i++] ^= *B; \ 00096 C = &WALK[PT1 ^ 3]; RES[i++] ^= *C; \ 00097 D = &WALK[PT2 ^ 6]; RES[i++] ^= *D; \ 00098 \ 00099 if( PTEST & 1 ) SWAP( A, C ); \ 00100 \ 00101 IN = (*A >> (5)) ^ (*A << (27)) ^ CLK; \ 00102 *A = (*B >> (6)) ^ (*B << (26)) ^ CLK; \ 00103 *B = IN; CLK = (int) hardclock(); \ 00104 *C = (*C >> (7)) ^ (*C << (25)) ^ CLK; \ 00105 *D = (*D >> (8)) ^ (*D << (24)) ^ CLK; \ 00106 \ 00107 A = &WALK[PT1 ^ 4]; \ 00108 B = &WALK[PT2 ^ 1]; \ 00109 \ 00110 PTEST = PT2 >> 1; \ 00111 \ 00112 PT2 = (RES[(i - 8) ^ PTY] ^ WALK[PT2 ^ PTY ^ 7]); \ 00113 PT2 = ((PT2 & 0x1FFF) & (~8)) ^ ((PT1 ^ 8) & 0x8); \ 00114 PTY = (PT2 >> 10) & 7; \ 00115 \ 00116 TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \ 00117 TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \ 00118 TST2_ENTER TST2_ENTER TST2_ENTER TST2_ENTER \ 00119 \ 00120 TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \ 00121 TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \ 00122 TST2_LEAVE TST2_LEAVE TST2_LEAVE TST2_LEAVE \ 00123 \ 00124 C = &WALK[PT1 ^ 5]; \ 00125 D = &WALK[PT2 ^ 5]; \ 00126 \ 00127 RES[i++] ^= *A; \ 00128 RES[i++] ^= *B; \ 00129 RES[i++] ^= *C; \ 00130 RES[i++] ^= *D; \ 00131 \ 00132 IN = (*A >> ( 9)) ^ (*A << (23)) ^ CLK; \ 00133 *A = (*B >> (10)) ^ (*B << (22)) ^ CLK; \ 00134 *B = IN ^ U2; \ 00135 *C = (*C >> (11)) ^ (*C << (21)) ^ CLK; \ 00136 *D = (*D >> (12)) ^ (*D << (20)) ^ CLK; \ 00137 \ 00138 A = &WALK[PT1 ^ 6]; RES[i++] ^= *A; \ 00139 B = &WALK[PT2 ^ 3]; RES[i++] ^= *B; \ 00140 C = &WALK[PT1 ^ 7]; RES[i++] ^= *C; \ 00141 D = &WALK[PT2 ^ 7]; RES[i++] ^= *D; \ 00142 \ 00143 IN = (*A >> (13)) ^ (*A << (19)) ^ CLK; \ 00144 *A = (*B >> (14)) ^ (*B << (18)) ^ CLK; \ 00145 *B = IN; \ 00146 *C = (*C >> (15)) ^ (*C << (17)) ^ CLK; \ 00147 *D = (*D >> (16)) ^ (*D << (16)) ^ CLK; \ 00148 \ 00149 PT1 = ( RES[(i - 8) ^ PTX] ^ \ 00150 WALK[PT1 ^ PTX ^ 7] ) & (~1); \ 00151 PT1 ^= (PT2 ^ 0x10) & 0x10; \ 00152 \ 00153 for( n++, i = 0; i < 16; i++ ) \ 00154 hs->pool[n % COLLECT_SIZE] ^= RES[i]; 00155 00156 /* 00157 * Entropy gathering function 00158 */ 00159 static void havege_fill( havege_state *hs ) 00160 { 00161 int i, n = 0; 00162 int U1, U2, *A, *B, *C, *D; 00163 int PT1, PT2, *WALK, RES[16]; 00164 int PTX, PTY, CLK, PTEST, IN; 00165 00166 WALK = hs->WALK; 00167 PT1 = hs->PT1; 00168 PT2 = hs->PT2; 00169 00170 PTX = U1 = 0; 00171 PTY = U2 = 0; 00172 00173 memset( RES, 0, sizeof( RES ) ); 00174 00175 while( n < COLLECT_SIZE * 4 ) 00176 { 00177 ONE_ITERATION 00178 ONE_ITERATION 00179 ONE_ITERATION 00180 ONE_ITERATION 00181 } 00182 00183 hs->PT1 = PT1; 00184 hs->PT2 = PT2; 00185 00186 hs->offset[0] = 0; 00187 hs->offset[1] = COLLECT_SIZE / 2; 00188 } 00189 00190 /* 00191 * HAVEGE initialization 00192 */ 00193 void havege_init( havege_state *hs ) 00194 { 00195 memset( hs, 0, sizeof( havege_state ) ); 00196 00197 havege_fill( hs ); 00198 } 00199 00200 /* 00201 * HAVEGE rand function 00202 */ 00203 int havege_random( void *p_rng, unsigned char *buf, size_t len ) 00204 { 00205 int val; 00206 size_t use_len; 00207 havege_state *hs = (havege_state *) p_rng; 00208 unsigned char *p = buf; 00209 00210 while( len > 0 ) 00211 { 00212 use_len = len; 00213 if( use_len > sizeof(int) ) 00214 use_len = sizeof(int); 00215 00216 if( hs->offset[1] >= COLLECT_SIZE ) 00217 havege_fill( hs ); 00218 00219 val = hs->pool[hs->offset[0]++]; 00220 val ^= hs->pool[hs->offset[1]++]; 00221 00222 memcpy( p, &val, use_len ); 00223 00224 len -= use_len; 00225 p += use_len; 00226 } 00227 00228 return( 0 ); 00229 } 00230 00231 #endif