ParagonIE_Sodium_Core_Ristretto255::ristretto255_elligator() –

You appear to be a bot. Output may be restricted

Description

Usage

$ParagonIE_Sodium_Core_Curve25519_Ge_P3 = ParagonIE_Sodium_Core_Ristretto255::ristretto255_elligator( $t );

Parameters

$t
( ParagonIE_Sodium_Core_Curve25519_Fe ) required

Returns

ParagonIE_Sodium_Core_Curve25519_Ge_P3

Source

File name: wordpress/wp-includes/sodium_compat/src/Core/Ristretto255.php


Lines:

1 to 67 of 67
    public static function ristretto255_elligator(ParagonIE_Sodium_Core_Curve25519_Fe $t)
    {
        $sqrtm1   = ParagonIE_Sodium_Core_Curve25519_Fe::ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(self::$sqrtm1);
        $onemsqd  = ParagonIE_Sodium_Core_Curve25519_Fe::ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(self::$onemsqd);
        $d        = ParagonIE_Sodium_Core_Curve25519_Fe::ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(self::$d);
        $sqdmone  = ParagonIE_Sodium_Core_Curve25519_Fe::ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(self::$sqdmone);
        $sqrtadm1 = ParagonIE_Sodium_Core_Curve25519_Fe::ParagonIE_Sodium_Core_Curve25519_Fe::fromArray(self::$sqrtadm1);

        $one = self::fe_1();
        $r   = self::fe_mul($sqrtm1, self::fe_sq($t));         /* r = sqrt(-1)*t^2 */
        $u   = self::fe_mul(self::fe_add($r, $one), $onemsqd); /* u = (r+1)*(1-d^2) */
        $c   = self::fe_neg(self::fe_1());                     /* c = -1 */
        $rpd = self::fe_add($r, $d);                           /* rpd = r+d */

        $v = self::fe_mul(
            self::fe_sub(
                $c,
                self::fe_mul($r, $d)
            ),
            $rpd
        ); /* v = (c-r*d)*(r+d) */

        $result = self::ristretto255_sqrt_ratio_m1($u, $v);
        $s = $result['x'];
        $wasnt_square = 1 - $result['nonsquare'];

        $s_prime = self::fe_neg(
            self::fe_abs(
                self::fe_mul($s, $t)
            )
        ); /* s_prime = -|s*t| */
        $s = self::fe_cmov($s, $s_prime, $wasnt_square);
        $c = self::fe_cmov($c, $r, $wasnt_square);

        // fe25519_sub(n, r, one);            /* n = r-1 */
        // fe25519_mul(n, n, c);              /* n = c*(r-1) */
        // fe25519_mul(n, n, ed25519_sqdmone); /* n = c*(r-1)*(d-1)^2 */
        // fe25519_sub(n, n, v);              /* n =  c*(r-1)*(d-1)^2-v */
        $n = self::fe_sub(
            self::fe_mul(
                self::fe_mul(
                    self::fe_sub($r, $one),
                    $c
                ),
                $sqdmone
            ),
            $v
        ); /* n =  c*(r-1)*(d-1)^2-v */

        $w0 = self::fe_mul(
            self::fe_add($s, $s),
            $v
        ); /* w0 = 2s*v */

        $w1 = self::fe_mul($n, $sqrtadm1); /* w1 = n*sqrt(ad-1) */
        $ss = self::fe_sq($s); /* ss = s^2 */
        $w2 = self::fe_sub($one, $ss); /* w2 = 1-s^2 */
        $w3 = self::fe_add($one, $ss); /* w3 = 1+s^2 */

        return new ParagonIE_Sodium_Core_Curve25519_Ge_P3(
            self::fe_mul($w0, $w3),
            self::fe_mul($w2, $w1),
            self::fe_mul($w1, $w3),
            self::fe_mul($w0, $w2)
        );
    }
 

 View on GitHub View on Trac