<?php

if (class_exists('ParagonIE_Sodium_Core32_X25519', false)) {
    return;
}
abstract class ParagonIE_Sodium_Core32_X25519 extends ParagonIE_Sodium_Core32_Curve25519
{
    public static function fe_cswap(ParagonIE_Sodium_Core32_Curve25519_Fe $f, ParagonIE_Sodium_Core32_Curve25519_Fe $g, $b = 0)
    {
        $f0 = (int) $f[0]->toInt();
        $f1 = (int) $f[1]->toInt();
        $f2 = (int) $f[2]->toInt();
        $f3 = (int) $f[3]->toInt();
        $f4 = (int) $f[4]->toInt();
        $f5 = (int) $f[5]->toInt();
        $f6 = (int) $f[6]->toInt();
        $f7 = (int) $f[7]->toInt();
        $f8 = (int) $f[8]->toInt();
        $f9 = (int) $f[9]->toInt();
        $g0 = (int) $g[0]->toInt();
        $g1 = (int) $g[1]->toInt();
        $g2 = (int) $g[2]->toInt();
        $g3 = (int) $g[3]->toInt();
        $g4 = (int) $g[4]->toInt();
        $g5 = (int) $g[5]->toInt();
        $g6 = (int) $g[6]->toInt();
        $g7 = (int) $g[7]->toInt();
        $g8 = (int) $g[8]->toInt();
        $g9 = (int) $g[9]->toInt();
        $b = -$b;
        $x0 = ($f0 ^ $g0) & $b;
        $x1 = ($f1 ^ $g1) & $b;
        $x2 = ($f2 ^ $g2) & $b;
        $x3 = ($f3 ^ $g3) & $b;
        $x4 = ($f4 ^ $g4) & $b;
        $x5 = ($f5 ^ $g5) & $b;
        $x6 = ($f6 ^ $g6) & $b;
        $x7 = ($f7 ^ $g7) & $b;
        $x8 = ($f8 ^ $g8) & $b;
        $x9 = ($f9 ^ $g9) & $b;
        $f[0] = ParagonIE_Sodium_Core32_Int32::fromInt($f0 ^ $x0);
        $f[1] = ParagonIE_Sodium_Core32_Int32::fromInt($f1 ^ $x1);
        $f[2] = ParagonIE_Sodium_Core32_Int32::fromInt($f2 ^ $x2);
        $f[3] = ParagonIE_Sodium_Core32_Int32::fromInt($f3 ^ $x3);
        $f[4] = ParagonIE_Sodium_Core32_Int32::fromInt($f4 ^ $x4);
        $f[5] = ParagonIE_Sodium_Core32_Int32::fromInt($f5 ^ $x5);
        $f[6] = ParagonIE_Sodium_Core32_Int32::fromInt($f6 ^ $x6);
        $f[7] = ParagonIE_Sodium_Core32_Int32::fromInt($f7 ^ $x7);
        $f[8] = ParagonIE_Sodium_Core32_Int32::fromInt($f8 ^ $x8);
        $f[9] = ParagonIE_Sodium_Core32_Int32::fromInt($f9 ^ $x9);
        $g[0] = ParagonIE_Sodium_Core32_Int32::fromInt($g0 ^ $x0);
        $g[1] = ParagonIE_Sodium_Core32_Int32::fromInt($g1 ^ $x1);
        $g[2] = ParagonIE_Sodium_Core32_Int32::fromInt($g2 ^ $x2);
        $g[3] = ParagonIE_Sodium_Core32_Int32::fromInt($g3 ^ $x3);
        $g[4] = ParagonIE_Sodium_Core32_Int32::fromInt($g4 ^ $x4);
        $g[5] = ParagonIE_Sodium_Core32_Int32::fromInt($g5 ^ $x5);
        $g[6] = ParagonIE_Sodium_Core32_Int32::fromInt($g6 ^ $x6);
        $g[7] = ParagonIE_Sodium_Core32_Int32::fromInt($g7 ^ $x7);
        $g[8] = ParagonIE_Sodium_Core32_Int32::fromInt($g8 ^ $x8);
        $g[9] = ParagonIE_Sodium_Core32_Int32::fromInt($g9 ^ $x9);
    }
    public static function fe_mul121666(ParagonIE_Sodium_Core32_Curve25519_Fe $f)
    {
        $h = array();
        for ($i = 0; $i < 10; ++$i) {
            $h[$i] = $f[$i]->toInt64()->mulInt(121666, 17);
        }
        $carry9 = $h[9]->addInt(1 << 24)->shiftRight(25);
        $h[0] = $h[0]->addInt64($carry9->mulInt(19, 5));
        $h[9] = $h[9]->subInt64($carry9->shiftLeft(25));
        $carry1 = $h[1]->addInt(1 << 24)->shiftRight(25);
        $h[2] = $h[2]->addInt64($carry1);
        $h[1] = $h[1]->subInt64($carry1->shiftLeft(25));
        $carry3 = $h[3]->addInt(1 << 24)->shiftRight(25);
        $h[4] = $h[4]->addInt64($carry3);
        $h[3] = $h[3]->subInt64($carry3->shiftLeft(25));
        $carry5 = $h[5]->addInt(1 << 24)->shiftRight(25);
        $h[6] = $h[6]->addInt64($carry5);
        $h[5] = $h[5]->subInt64($carry5->shiftLeft(25));
        $carry7 = $h[7]->addInt(1 << 24)->shiftRight(25);
        $h[8] = $h[8]->addInt64($carry7);
        $h[7] = $h[7]->subInt64($carry7->shiftLeft(25));
        $carry0 = $h[0]->addInt(1 << 25)->shiftRight(26);
        $h[1] = $h[1]->addInt64($carry0);
        $h[0] = $h[0]->subInt64($carry0->shiftLeft(26));
        $carry2 = $h[2]->addInt(1 << 25)->shiftRight(26);
        $h[3] = $h[3]->addInt64($carry2);
        $h[2] = $h[2]->subInt64($carry2->shiftLeft(26));
        $carry4 = $h[4]->addInt(1 << 25)->shiftRight(26);
        $h[5] = $h[5]->addInt64($carry4);
        $h[4] = $h[4]->subInt64($carry4->shiftLeft(26));
        $carry6 = $h[6]->addInt(1 << 25)->shiftRight(26);
        $h[7] = $h[7]->addInt64($carry6);
        $h[6] = $h[6]->subInt64($carry6->shiftLeft(26));
        $carry8 = $h[8]->addInt(1 << 25)->shiftRight(26);
        $h[9] = $h[9]->addInt64($carry8);
        $h[8] = $h[8]->subInt64($carry8->shiftLeft(26));
        for ($i = 0; $i < 10; ++$i) {
            $h[$i] = $h[$i]->toInt32();
        }
        $h2 = $h;
        return ParagonIE_Sodium_Core32_Curve25519_Fe::fromArray($h2);
    }
    public static function crypto_scalarmult_curve25519_ref10($n, $p)
    {
        $e = '' . $n;
        $e[0] = self::intToChr(self::chrToInt($e[0]) & 248);
        $e[31] = self::intToChr(self::chrToInt($e[31]) & 127 | 64);
        $x1 = self::fe_frombytes($p);
        $x2 = self::fe_1();
        $z2 = self::fe_0();
        $x3 = self::fe_copy($x1);
        $z3 = self::fe_1();
        $swap = 0;
        for ($pos = 254; $pos >= 0; --$pos) {
            $b = self::chrToInt($e[(int) floor($pos / 8)]) >> ($pos & 7);
            $b &= 1;
            $swap ^= $b;
            self::fe_cswap($x2, $x3, $swap);
            self::fe_cswap($z2, $z3, $swap);
            $swap = $b;
            $tmp0 = self::fe_sub($x3, $z3);
            $tmp1 = self::fe_sub($x2, $z2);
            $x2 = self::fe_add($x2, $z2);
            $z2 = self::fe_add($x3, $z3);
            $z3 = self::fe_mul($tmp0, $x2);
            $z2 = self::fe_mul($z2, $tmp1);
            $tmp0 = self::fe_sq($tmp1);
            $tmp1 = self::fe_sq($x2);
            $x3 = self::fe_add($z3, $z2);
            $z2 = self::fe_sub($z3, $z2);
            $x2 = self::fe_mul($tmp1, $tmp0);
            $tmp1 = self::fe_sub($tmp1, $tmp0);
            $z2 = self::fe_sq($z2);
            $z3 = self::fe_mul121666($tmp1);
            $x3 = self::fe_sq($x3);
            $tmp0 = self::fe_add($tmp0, $z3);
            $z3 = self::fe_mul($x1, $z2);
            $z2 = self::fe_mul($tmp1, $tmp0);
        }
        self::fe_cswap($x2, $x3, $swap);
        self::fe_cswap($z2, $z3, $swap);
        $z2 = self::fe_invert($z2);
        $x2 = self::fe_mul($x2, $z2);
        return (string) self::fe_tobytes($x2);
    }
    public static function edwards_to_montgomery(ParagonIE_Sodium_Core32_Curve25519_Fe $edwardsY, ParagonIE_Sodium_Core32_Curve25519_Fe $edwardsZ)
    {
        $tempX = self::fe_add($edwardsZ, $edwardsY);
        $tempZ = self::fe_sub($edwardsZ, $edwardsY);
        $tempZ = self::fe_invert($tempZ);
        return self::fe_mul($tempX, $tempZ);
    }
    public static function crypto_scalarmult_curve25519_ref10_base($n)
    {
        $e = '' . $n;
        $e[0] = self::intToChr(self::chrToInt($e[0]) & 248);
        $e[31] = self::intToChr(self::chrToInt($e[31]) & 127 | 64);
        $A = self::ge_scalarmult_base($e);
        if (!$A->Y instanceof ParagonIE_Sodium_Core32_Curve25519_Fe || !$A->Z instanceof ParagonIE_Sodium_Core32_Curve25519_Fe) {
            throw new TypeError('Null points encountered');
        }
        $pk = self::edwards_to_montgomery($A->Y, $A->Z);
        return self::fe_tobytes($pk);
    }
}