ParagonIE_Sodium_Core_X25519::crypto_scalarmult_curve25519_ref10() public WP 1.0

{} Это метод класса: ParagonIE_Sodium_Core_X25519{}

Хуков нет.

Возвращает

Строку.

Использование

$result = ParagonIE_Sodium_Core_X25519::crypto_scalarmult_curve25519_ref10( $n, $p );

$n(строка) (обязательный)

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$p(строка) (обязательный)

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Код ParagonIE_Sodium_Core_X25519::crypto_scalarmult_curve25519_ref10() ParagonIE Sodium Core X25519::crypto scalarmult curve25519 ref10 ^{WP 5.8.1}

public static function crypto_scalarmult_curve25519_ref10($n, $p)
{
    # for (i = 0;i < 32;++i) e[i] = n[i];
    $e = '' . $n;
    # e[0] &= 248;
    $e[0] = self::intToChr(
        self::chrToInt($e[0]) & 248
    );
    # e[31] &= 127;
    # e[31] |= 64;
    $e[31] = self::intToChr(
        (self::chrToInt($e[31]) & 127) | 64
    );
    # fe_frombytes(x1,p);
    $x1 = self::fe_frombytes($p);
    # fe_1(x2);
    $x2 = self::fe_1();
    # fe_0(z2);
    $z2 = self::fe_0();
    # fe_copy(x3,x1);
    $x3 = self::fe_copy($x1);
    # fe_1(z3);
    $z3 = self::fe_1();

    # swap = 0;
    /** @var int $swap */
    $swap = 0;

    # for (pos = 254;pos >= 0;--pos) {
    for ($pos = 254; $pos >= 0; --$pos) {
        # b = e[pos / 8] >> (pos & 7);
        /** @var int $b */
        $b = self::chrToInt(
                $e[(int) floor($pos / 8)]
            ) >> ($pos & 7);
        # b &= 1;
        $b &= 1;
        # swap ^= b;
        $swap ^= $b;
        # fe_cswap(x2,x3,swap);
        self::fe_cswap($x2, $x3, $swap);
        # fe_cswap(z2,z3,swap);
        self::fe_cswap($z2, $z3, $swap);
        # swap = b;
        $swap = $b;
        # fe_sub(tmp0,x3,z3);
        $tmp0 = self::fe_sub($x3, $z3);
        # fe_sub(tmp1,x2,z2);
        $tmp1 = self::fe_sub($x2, $z2);

        # fe_add(x2,x2,z2);
        $x2 = self::fe_add($x2, $z2);

        # fe_add(z2,x3,z3);
        $z2 = self::fe_add($x3, $z3);

        # fe_mul(z3,tmp0,x2);
        $z3 = self::fe_mul($tmp0, $x2);

        # fe_mul(z2,z2,tmp1);
        $z2 = self::fe_mul($z2, $tmp1);

        # fe_sq(tmp0,tmp1);
        $tmp0 = self::fe_sq($tmp1);

        # fe_sq(tmp1,x2);
        $tmp1 = self::fe_sq($x2);

        # fe_add(x3,z3,z2);
        $x3 = self::fe_add($z3, $z2);

        # fe_sub(z2,z3,z2);
        $z2 = self::fe_sub($z3, $z2);

        # fe_mul(x2,tmp1,tmp0);
        $x2 = self::fe_mul($tmp1, $tmp0);

        # fe_sub(tmp1,tmp1,tmp0);
        $tmp1 = self::fe_sub($tmp1, $tmp0);

        # fe_sq(z2,z2);
        $z2 = self::fe_sq($z2);

        # fe_mul121666(z3,tmp1);
        $z3 = self::fe_mul121666($tmp1);

        # fe_sq(x3,x3);
        $x3 = self::fe_sq($x3);

        # fe_add(tmp0,tmp0,z3);
        $tmp0 = self::fe_add($tmp0, $z3);

        # fe_mul(z3,x1,z2);
        $z3 = self::fe_mul($x1, $z2);

        # fe_mul(z2,tmp1,tmp0);
        $z2 = self::fe_mul($tmp1, $tmp0);
    }

    # fe_cswap(x2,x3,swap);
    self::fe_cswap($x2, $x3, $swap);

    # fe_cswap(z2,z3,swap);
    self::fe_cswap($z2, $z3, $swap);

    # fe_invert(z2,z2);
    $z2 = self::fe_invert($z2);

    # fe_mul(x2,x2,z2);
    $x2 = self::fe_mul($x2, $z2);
    # fe_tobytes(q,x2);
    return self::fe_tobytes($x2);
}