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        $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 application83     *84     * @param ParagonIE_Sodium_Core_Curve25519_Fe $f85     * @return ParagonIE_Sodium_Core_Curve25519_Fe86     */87    public static function fe_mul121666(ParagonIE_Sodium_Core_Curve25519_Fe $f)88    {89        $h = array(