ParagonIE_Sodium_Core_X25519

10abstract class ParagonIE_Sodium_Core_X25519 extends ParagonIE_Sodium_Core_Curve2551911{12    /**13     * Alters the objects passed to this method in place.14     *15     * @internal You should not use this directly from another application16     *17     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f18     * @param ParagonIE_Sodium_Core_Curve25519_Fe $g19     * @param int $b20     * @return void21     * @psalm-suppress MixedAssignment22     */23    public static function fe_cswap(24        ParagonIE_Sodium_Core_Curve25519_Fe $f,25        ParagonIE_Sodium_Core_Curve25519_Fe $g,26        $b = 027    ) {28        $b = -$b;29        $x0 = ($f->e0 ^ $g->e0) & $b;30        $x1 = ($f->e1 ^ $g->e1) & $b;31        $x2 = ($f->e2 ^ $g->e2) & $b;32        $x3 = ($f->e3 ^ $g->e3) & $b;33        $x4 = ($f->e4 ^ $g->e4) & $b;34        $x5 = ($f->e5 ^ $g->e5) & $b;35        $x6 = ($f->e6 ^ $g->e6) & $b;36        $x7 = ($f->e7 ^ $g->e7) & $b;37        $x8 = ($f->e8 ^ $g->e8) & $b;38        $x9 = ($f->e9 ^ $g->e9) & $b;39        $f->e0 ^= $x0;40        $f->e1 ^= $x1;41        $f->e2 ^= $x2;42        $f->e3 ^= $x3;43        $f->e4 ^= $x4;44        $f->e5 ^= $x5;45        $f->e6 ^= $x6;46        $f->e7 ^= $x7;47        $f->e8 ^= $x8;48        $f->e9 ^= $x9;49        $g->e0 ^= $x0;50        $g->e1 ^= $x1;51        $g->e2 ^= $x2;52        $g->e3 ^= $x3;53        $g->e4 ^= $x4;54        $g->e5 ^= $x5;55        $g->e6 ^= $x6;56        $g->e7 ^= $x7;57        $g->e8 ^= $x8;58        $g->e9 ^= $x9;59    }60 61    /**62     * @internal You should not use this directly from another application63     *64     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f65     * @return ParagonIE_Sodium_Core_Curve25519_Fe66     */67    public static function fe_mul121666(ParagonIE_Sodium_Core_Curve25519_Fe $f)68    {69        $h0 = self::mul($f->e0, 121666, 17);70        $h1 = self::mul($f->e1, 121666, 17);71        $h2 = self::mul($f->e2, 121666, 17);72        $h3 = self::mul($f->e3, 121666, 17);73        $h4 = self::mul($f->e4, 121666, 17);74        $h5 = self::mul($f->e5, 121666, 17);75        $h6 = self::mul($f->e6, 121666, 17);76        $h7 = self::mul($f->e7, 121666, 17);77        $h8 = self::mul($f->e8, 121666, 17);78        $h9 = self::mul($f->e9, 121666, 17);79 80        $carry9 = ($h9 + (1 << 24)) >> 25;81        $h0 += self::mul($carry9, 19, 5);82        $h9 -= $carry9 << 25;83 84        $carry1 = ($h1 + (1 << 24)) >> 25;85        $h2 += $carry1;86        $h1 -= $carry1 << 25;87 88        $carry3 = ($h3 + (1 << 24)) >> 25;89        $h4 += $carry3;