[Summary view] [Print] [Text view]

   1  <?php
   2  
   3  if (class_exists('ParagonIE_Sodium_Core_X25519', false)) {
   4      return;
   5  }
   6  
   7  /**
   8   * Class ParagonIE_Sodium_Core_X25519
   9   */
  10  abstract class ParagonIE_Sodium_Core_X25519 extends ParagonIE_Sodium_Core_Curve25519
  11  {
  12      /**
  13       * Alters the objects passed to this method in place.
  14       *
  15       * @internal You should not use this directly from another application
  16       *
  17       * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
  18       * @param ParagonIE_Sodium_Core_Curve25519_Fe $g
  19       * @param int $b
  20       * @return void
  21       * @psalm-suppress MixedAssignment
  22       */
  23      public static function fe_cswap(
  24          ParagonIE_Sodium_Core_Curve25519_Fe $f,
  25          ParagonIE_Sodium_Core_Curve25519_Fe $g,
  26          $b = 0
  27      ) {
  28          $f0 = (int) $f[0];
  29          $f1 = (int) $f[1];
  30          $f2 = (int) $f[2];
  31          $f3 = (int) $f[3];
  32          $f4 = (int) $f[4];
  33          $f5 = (int) $f[5];
  34          $f6 = (int) $f[6];
  35          $f7 = (int) $f[7];
  36          $f8 = (int) $f[8];
  37          $f9 = (int) $f[9];
  38          $g0 = (int) $g[0];
  39          $g1 = (int) $g[1];
  40          $g2 = (int) $g[2];
  41          $g3 = (int) $g[3];
  42          $g4 = (int) $g[4];
  43          $g5 = (int) $g[5];
  44          $g6 = (int) $g[6];
  45          $g7 = (int) $g[7];
  46          $g8 = (int) $g[8];
  47          $g9 = (int) $g[9];
  48          $b = -$b;
  49          $x0 = ($f0 ^ $g0) & $b;
  50          $x1 = ($f1 ^ $g1) & $b;
  51          $x2 = ($f2 ^ $g2) & $b;
  52          $x3 = ($f3 ^ $g3) & $b;
  53          $x4 = ($f4 ^ $g4) & $b;
  54          $x5 = ($f5 ^ $g5) & $b;
  55          $x6 = ($f6 ^ $g6) & $b;
  56          $x7 = ($f7 ^ $g7) & $b;
  57          $x8 = ($f8 ^ $g8) & $b;
  58          $x9 = ($f9 ^ $g9) & $b;
  59          $f[0] = $f0 ^ $x0;
  60          $f[1] = $f1 ^ $x1;
  61          $f[2] = $f2 ^ $x2;
  62          $f[3] = $f3 ^ $x3;
  63          $f[4] = $f4 ^ $x4;
  64          $f[5] = $f5 ^ $x5;
  65          $f[6] = $f6 ^ $x6;
  66          $f[7] = $f7 ^ $x7;
  67          $f[8] = $f8 ^ $x8;
  68          $f[9] = $f9 ^ $x9;
  69          $g[0] = $g0 ^ $x0;
  70          $g[1] = $g1 ^ $x1;
  71          $g[2] = $g2 ^ $x2;
  72          $g[3] = $g3 ^ $x3;
  73          $g[4] = $g4 ^ $x4;
  74          $g[5] = $g5 ^ $x5;
  75          $g[6] = $g6 ^ $x6;
  76          $g[7] = $g7 ^ $x7;
  77          $g[8] = $g8 ^ $x8;
  78          $g[9] = $g9 ^ $x9;
  79      }
  80  
  81      /**
  82       * @internal You should not use this directly from another application
  83       *
  84       * @param ParagonIE_Sodium_Core_Curve25519_Fe $f
  85       * @return ParagonIE_Sodium_Core_Curve25519_Fe
  86       */
  87      public static function fe_mul121666(ParagonIE_Sodium_Core_Curve25519_Fe $f)
  88      {
  89          $h = array(
  90              self::mul((int) $f[0], 121666, 17),
  91              self::mul((int) $f[1], 121666, 17),
  92              self::mul((int) $f[2], 121666, 17),
  93              self::mul((int) $f[3], 121666, 17),
  94              self::mul((int) $f[4], 121666, 17),
  95              self::mul((int) $f[5], 121666, 17),
  96              self::mul((int) $f[6], 121666, 17),
  97              self::mul((int) $f[7], 121666, 17),
  98              self::mul((int) $f[8], 121666, 17),
  99              self::mul((int) $f[9], 121666, 17)
 100          );
 101  
 102          /** @var int $carry9 */
 103          $carry9 = ($h[9] + (1 << 24)) >> 25;
 104          $h[0] += self::mul($carry9, 19, 5);
 105          $h[9] -= $carry9 << 25;
 106          /** @var int $carry1 */
 107          $carry1 = ($h[1] + (1 << 24)) >> 25;
 108          $h[2] += $carry1;
 109          $h[1] -= $carry1 << 25;
 110          /** @var int $carry3 */
 111          $carry3 = ($h[3] + (1 << 24)) >> 25;
 112          $h[4] += $carry3;
 113          $h[3] -= $carry3 << 25;
 114          /** @var int $carry5 */
 115          $carry5 = ($h[5] + (1 << 24)) >> 25;
 116          $h[6] += $carry5;
 117          $h[5] -= $carry5 << 25;
 118          /** @var int $carry7 */
 119          $carry7 = ($h[7] + (1 << 24)) >> 25;
 120          $h[8] += $carry7;
 121          $h[7] -= $carry7 << 25;
 122  
 123          /** @var int $carry0 */
 124          $carry0 = ($h[0] + (1 << 25)) >> 26;
 125          $h[1] += $carry0;
 126          $h[0] -= $carry0 << 26;
 127          /** @var int $carry2 */
 128          $carry2 = ($h[2] + (1 << 25)) >> 26;
 129          $h[3] += $carry2;
 130          $h[2] -= $carry2 << 26;
 131          /** @var int $carry4 */
 132          $carry4 = ($h[4] + (1 << 25)) >> 26;
 133          $h[5] += $carry4;
 134          $h[4] -= $carry4 << 26;
 135          /** @var int $carry6 */
 136          $carry6 = ($h[6] + (1 << 25)) >> 26;
 137          $h[7] += $carry6;
 138          $h[6] -= $carry6 << 26;
 139          /** @var int $carry8 */
 140          $carry8 = ($h[8] + (1 << 25)) >> 26;
 141          $h[9] += $carry8;
 142          $h[8] -= $carry8 << 26;
 143  
 144          foreach ($h as $i => $value) {
 145              $h[$i] = (int) $value;
 146          }
 147          return ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($h);
 148      }
 149  
 150      /**
 151       * @internal You should not use this directly from another application
 152       *
 153       * Inline comments preceded by # are from libsodium's ref10 code.
 154       *
 155       * @param string $n
 156       * @param string $p
 157       * @return string
 158       * @throws SodiumException
 159       * @throws TypeError
 160       */
 161      public static function crypto_scalarmult_curve25519_ref10($n, $p)
 162      {
 163          # for (i = 0;i < 32;++i) e[i] = n[i];
 164          $e = '' . $n;
 165          # e[0] &= 248;
 166          $e[0] = self::intToChr(
 167              self::chrToInt($e[0]) & 248
 168          );
 169          # e[31] &= 127;
 170          # e[31] |= 64;
 171          $e[31] = self::intToChr(
 172              (self::chrToInt($e[31]) & 127) | 64
 173          );
 174          # fe_frombytes(x1,p);
 175          $x1 = self::fe_frombytes($p);
 176          # fe_1(x2);
 177          $x2 = self::fe_1();
 178          # fe_0(z2);
 179          $z2 = self::fe_0();
 180          # fe_copy(x3,x1);
 181          $x3 = self::fe_copy($x1);
 182          # fe_1(z3);
 183          $z3 = self::fe_1();
 184  
 185          # swap = 0;
 186          /** @var int $swap */
 187          $swap = 0;
 188  
 189          # for (pos = 254;pos >= 0;--pos) {
 190          for ($pos = 254; $pos >= 0; --$pos) {
 191              # b = e[pos / 8] >> (pos & 7);
 192              /** @var int $b */
 193              $b = self::chrToInt(
 194                      $e[(int) floor($pos / 8)]
 195                  ) >> ($pos & 7);
 196              # b &= 1;
 197              $b &= 1;
 198              # swap ^= b;
 199              $swap ^= $b;
 200              # fe_cswap(x2,x3,swap);
 201              self::fe_cswap($x2, $x3, $swap);
 202              # fe_cswap(z2,z3,swap);
 203              self::fe_cswap($z2, $z3, $swap);
 204              # swap = b;
 205              $swap = $b;
 206              # fe_sub(tmp0,x3,z3);
 207              $tmp0 = self::fe_sub($x3, $z3);
 208              # fe_sub(tmp1,x2,z2);
 209              $tmp1 = self::fe_sub($x2, $z2);
 210  
 211              # fe_add(x2,x2,z2);
 212              $x2 = self::fe_add($x2, $z2);
 213  
 214              # fe_add(z2,x3,z3);
 215              $z2 = self::fe_add($x3, $z3);
 216  
 217              # fe_mul(z3,tmp0,x2);
 218              $z3 = self::fe_mul($tmp0, $x2);
 219  
 220              # fe_mul(z2,z2,tmp1);
 221              $z2 = self::fe_mul($z2, $tmp1);
 222  
 223              # fe_sq(tmp0,tmp1);
 224              $tmp0 = self::fe_sq($tmp1);
 225  
 226              # fe_sq(tmp1,x2);
 227              $tmp1 = self::fe_sq($x2);
 228  
 229              # fe_add(x3,z3,z2);
 230              $x3 = self::fe_add($z3, $z2);
 231  
 232              # fe_sub(z2,z3,z2);
 233              $z2 = self::fe_sub($z3, $z2);
 234  
 235              # fe_mul(x2,tmp1,tmp0);
 236              $x2 = self::fe_mul($tmp1, $tmp0);
 237  
 238              # fe_sub(tmp1,tmp1,tmp0);
 239              $tmp1 = self::fe_sub($tmp1, $tmp0);
 240  
 241              # fe_sq(z2,z2);
 242              $z2 = self::fe_sq($z2);
 243  
 244              # fe_mul121666(z3,tmp1);
 245              $z3 = self::fe_mul121666($tmp1);
 246  
 247              # fe_sq(x3,x3);
 248              $x3 = self::fe_sq($x3);
 249  
 250              # fe_add(tmp0,tmp0,z3);
 251              $tmp0 = self::fe_add($tmp0, $z3);
 252  
 253              # fe_mul(z3,x1,z2);
 254              $z3 = self::fe_mul($x1, $z2);
 255  
 256              # fe_mul(z2,tmp1,tmp0);
 257              $z2 = self::fe_mul($tmp1, $tmp0);
 258          }
 259  
 260          # fe_cswap(x2,x3,swap);
 261          self::fe_cswap($x2, $x3, $swap);
 262  
 263          # fe_cswap(z2,z3,swap);
 264          self::fe_cswap($z2, $z3, $swap);
 265  
 266          # fe_invert(z2,z2);
 267          $z2 = self::fe_invert($z2);
 268  
 269          # fe_mul(x2,x2,z2);
 270          $x2 = self::fe_mul($x2, $z2);
 271          # fe_tobytes(q,x2);
 272          return self::fe_tobytes($x2);
 273      }
 274  
 275      /**
 276       * @internal You should not use this directly from another application
 277       *
 278       * @param ParagonIE_Sodium_Core_Curve25519_Fe $edwardsY
 279       * @param ParagonIE_Sodium_Core_Curve25519_Fe $edwardsZ
 280       * @return ParagonIE_Sodium_Core_Curve25519_Fe
 281       */
 282      public static function edwards_to_montgomery(
 283          ParagonIE_Sodium_Core_Curve25519_Fe $edwardsY,
 284          ParagonIE_Sodium_Core_Curve25519_Fe $edwardsZ
 285      ) {
 286          $tempX = self::fe_add($edwardsZ, $edwardsY);
 287          $tempZ = self::fe_sub($edwardsZ, $edwardsY);
 288          $tempZ = self::fe_invert($tempZ);
 289          return self::fe_mul($tempX, $tempZ);
 290      }
 291  
 292      /**
 293       * @internal You should not use this directly from another application
 294       *
 295       * @param string $n
 296       * @return string
 297       * @throws SodiumException
 298       * @throws TypeError
 299       */
 300      public static function crypto_scalarmult_curve25519_ref10_base($n)
 301      {
 302          # for (i = 0;i < 32;++i) e[i] = n[i];
 303          $e = '' . $n;
 304  
 305          # e[0] &= 248;
 306          $e[0] = self::intToChr(
 307              self::chrToInt($e[0]) & 248
 308          );
 309  
 310          # e[31] &= 127;
 311          # e[31] |= 64;
 312          $e[31] = self::intToChr(
 313              (self::chrToInt($e[31]) & 127) | 64
 314          );
 315  
 316          $A = self::ge_scalarmult_base($e);
 317          if (
 318              !($A->Y instanceof ParagonIE_Sodium_Core_Curve25519_Fe)
 319                  ||
 320              !($A->Z instanceof ParagonIE_Sodium_Core_Curve25519_Fe)
 321          ) {
 322              throw new TypeError('Null points encountered');
 323          }
 324          $pk = self::edwards_to_montgomery($A->Y, $A->Z);
 325          return self::fe_tobytes($pk);
 326      }
 327  }