<?php

if (class_exists('ParagonIE_Sodium_Core_Ed25519', false)) {
    return;
}
if (!class_exists('ParagonIE_Sodium_Core_Curve25519', false)) {
    require_once dirname(__FILE__) . '/Curve25519.php';
}




abstract class ParagonIE_Sodium_Core_Ed25519 extends ParagonIE_Sodium_Core_Curve25519
{
    const KEYPAIR_BYTES = 96;
    const SEED_BYTES = 32;
    const SCALAR_BYTES = 32;

    







    public static function keypair()
    {
        $seed = random_bytes(self::SEED_BYTES);
        $pk = '';
        $sk = '';
        self::seed_keypair($pk, $sk, $seed);
        return $sk . $pk;
    }

    









    public static function seed_keypair(&$pk, &$sk, $seed)
    {
        if (self::strlen($seed) !== self::SEED_BYTES) {
            throw new SodiumException('crypto_sign keypair seed must be 32 bytes long');
        }

         
        $pk = self::publickey_from_secretkey($seed);
        $sk = $seed . $pk;
        return $sk;
    }

    






    public static function secretkey($keypair)
    {
        if (self::strlen($keypair) !== self::KEYPAIR_BYTES) {
            throw new SodiumException('crypto_sign keypair must be 96 bytes long');
        }
        return self::substr($keypair, 0, 64);
    }

    






    public static function publickey($keypair)
    {
        if (self::strlen($keypair) !== self::KEYPAIR_BYTES) {
            throw new SodiumException('crypto_sign keypair must be 96 bytes long');
        }
        return self::substr($keypair, 64, 32);
    }

    







    public static function publickey_from_secretkey($sk)
    {
         
        $sk = hash('sha512', self::substr($sk, 0, 32), true);
        $sk[0] = self::intToChr(
            self::chrToInt($sk[0]) & 248
        );
        $sk[31] = self::intToChr(
            (self::chrToInt($sk[31]) & 63) | 64
        );
        return self::sk_to_pk($sk);
    }

    








    public static function is_on_main_subgroup(ParagonIE_Sodium_Core_Curve25519_Ge_P3 $A)
    {
        $p1 = self::ge_mul_l($A);
        $t = self::fe_sub($p1->Y, $p1->Z);
        return self::fe_isnonzero($p1->X) && self::fe_isnonzero($t);
    }

    





    public static function pk_to_curve25519($pk)
    {
        if (self::small_order($pk)) {
            throw new SodiumException('Public key is on a small order');
        }
        $A = self::ge_frombytes_negate_vartime(self::substr($pk, 0, 32));
        if (!self::is_on_main_subgroup($A)) {
            throw new SodiumException('Public key is not on a member of the main subgroup');
        }

         
         
         
        $one_minux_y = self::fe_invert(
            self::fe_sub(
                self::fe_1(),
                $A->Y
            )
        );

         
         
         
        $x = self::fe_mul(
            self::fe_add(self::fe_1(), $A->Y),
            $one_minux_y
        );

         
        return self::fe_tobytes($x);
    }

    







    public static function sk_to_pk($sk)
    {
        return self::ge_p3_tobytes(
            self::ge_scalarmult_base(
                self::substr($sk, 0, 32)
            )
        );
    }

    








    public static function sign($message, $sk)
    {
         
        $signature = self::sign_detached($message, $sk);
        return $signature . $message;
    }

    








    public static function sign_open($message, $pk)
    {
         
        $signature = self::substr($message, 0, 64);

         
        $message = self::substr($message, 64);

        if (self::verify_detached($signature, $message, $pk)) {
            return $message;
        }
        throw new SodiumException('Invalid signature');
    }

    








    public static function sign_detached($message, $sk)
    {
        if (self::strlen($sk) !== 64) {
            throw new SodiumException('Argument 2 must be CRYPTO_SIGN_SECRETKEYBYTES long');
        }
         
        $az =  hash('sha512', self::substr($sk, 0, 32), true);

         
         
         
        $az[0] = self::intToChr(self::chrToInt($az[0]) & 248);
        $az[31] = self::intToChr((self::chrToInt($az[31]) & 63) | 64);

         
         
         
         
        $hs = hash_init('sha512');
        hash_update($hs, self::substr($az, 32, 32));
        hash_update($hs, $message);
        $nonceHash = hash_final($hs, true);

         
        $pk = self::substr($sk, 32, 32);

         
         
         
        $nonce = self::sc_reduce($nonceHash) . self::substr($nonceHash, 32);
        $sig = self::ge_p3_tobytes(
            self::ge_scalarmult_base($nonce)
        );

         
         
         
         
        $hs = hash_init('sha512');
        hash_update($hs, self::substr($sig, 0, 32));
        hash_update($hs, self::substr($pk, 0, 32));
        hash_update($hs, $message);
        $hramHash = hash_final($hs, true);

         
         
        $hram = self::sc_reduce($hramHash);
        $sigAfter = self::sc_muladd($hram, $az, $nonce);
        $sig = self::substr($sig, 0, 32) . self::substr($sigAfter, 0, 32);

        try {
            ParagonIE_Sodium_Compat::memzero($az);
        } catch (SodiumException $ex) {
            $az = null;
        }
        return $sig;
    }

    









    public static function verify_detached($sig, $message, $pk)
    {
        if (self::strlen($sig) !== 64) {
            throw new SodiumException('Argument 1 must be CRYPTO_SIGN_BYTES long');
        }
        if (self::strlen($pk) !== 32) {
            throw new SodiumException('Argument 3 must be CRYPTO_SIGN_PUBLICKEYBYTES long');
        }
        if ((self::chrToInt($sig[63]) & 240) && self::check_S_lt_L(self::substr($sig, 32, 32))) {
            throw new SodiumException('S >= L - Invalid signature');
        }
        if (self::small_order($sig)) {
            throw new SodiumException('Signature is on too small of an order');
        }
        if ((self::chrToInt($sig[63]) & 224) !== 0) {
            throw new SodiumException('Invalid signature');
        }
        $d = 0;
        for ($i = 0; $i < 32; ++$i) {
            $d |= self::chrToInt($pk[$i]);
        }
        if ($d === 0) {
            throw new SodiumException('All zero public key');
        }

         
        $orig = ParagonIE_Sodium_Compat::$fastMult;

         
        ParagonIE_Sodium_Compat::$fastMult = true;

         
        $A = self::ge_frombytes_negate_vartime($pk);
        if (!self::is_on_main_subgroup($A)) {
            throw new SodiumException('Public key is not on a member of the main subgroup');
        }

         
        $hDigest = hash(
            'sha512',
            self::substr($sig, 0, 32) .
                self::substr($pk, 0, 32) .
                $message,
            true
        );

         
        $h = self::sc_reduce($hDigest) . self::substr($hDigest, 32);

         
        $R = self::ge_double_scalarmult_vartime(
            $h,
            $A,
            self::substr($sig, 32)
        );

         
        $rcheck = self::ge_tobytes($R);

         
        ParagonIE_Sodium_Compat::$fastMult = $orig;

        return self::verify_32($rcheck, self::substr($sig, 0, 32));
    }

    







    public static function check_S_lt_L($S)
    {
        if (self::strlen($S) < 32) {
            throw new SodiumException('Signature must be 32 bytes');
        }
        $L = array(
            0xed, 0xd3, 0xf5, 0x5c, 0x1a, 0x63, 0x12, 0x58,
            0xd6, 0x9c, 0xf7, 0xa2, 0xde, 0xf9, 0xde, 0x14,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10
        );
        $c = 0;
        $n = 1;
        $i = 32;

         
        do {
            --$i;
            $x = self::chrToInt($S[$i]);
            $c |= (
                (($x - $L[$i]) >> 8) & $n
            );
            $n &= (
                (($x ^ $L[$i]) - 1) >> 8
            );
        } while ($i !== 0);

        return $c === 0;
    }

    





    public static function small_order($R)
    {
         
        $blocklist = array(
             
            array(
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
            ),
             
            array(
                0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
            ),
             
            array(
                0x26, 0xe8, 0x95, 0x8f, 0xc2, 0xb2, 0x27, 0xb0,
                0x45, 0xc3, 0xf4, 0x89, 0xf2, 0xef, 0x98, 0xf0,
                0xd5, 0xdf, 0xac, 0x05, 0xd3, 0xc6, 0x33, 0x39,
                0xb1, 0x38, 0x02, 0x88, 0x6d, 0x53, 0xfc, 0x05
            ),
             
            array(
                0xc7, 0x17, 0x6a, 0x70, 0x3d, 0x4d, 0xd8, 0x4f,
                0xba, 0x3c, 0x0b, 0x76, 0x0d, 0x10, 0x67, 0x0f,
                0x2a, 0x20, 0x53, 0xfa, 0x2c, 0x39, 0xcc, 0xc6,
                0x4e, 0xc7, 0xfd, 0x77, 0x92, 0xac, 0x03, 0x7a
            ),
             
            array(
                0x13, 0xe8, 0x95, 0x8f, 0xc2, 0xb2, 0x27, 0xb0,
                0x45, 0xc3, 0xf4, 0x89, 0xf2, 0xef, 0x98, 0xf0,
                0xd5, 0xdf, 0xac, 0x05, 0xd3, 0xc6, 0x33, 0x39,
                0xb1, 0x38, 0x02, 0x88, 0x6d, 0x53, 0xfc, 0x85
            ),
             
            array(
                0xb4, 0x17, 0x6a, 0x70, 0x3d, 0x4d, 0xd8, 0x4f,
                0xba, 0x3c, 0x0b, 0x76, 0x0d, 0x10, 0x67, 0x0f,
                0x2a, 0x20, 0x53, 0xfa, 0x2c, 0x39, 0xcc, 0xc6,
                0x4e, 0xc7, 0xfd, 0x77, 0x92, 0xac, 0x03, 0xfa
            ),
             
            array(
                0xec, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f
            ),
             
            array(
                0xed, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f
            ),
             
            array(
                0xee, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f
            ),
             
            array(
                0xd9, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
            ),
             
            array(
                0xda, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
            ),
             
            array(
                0xdb, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
            )
        );
         
        $countBlocklist = count($blocklist);

        for ($i = 0; $i < $countBlocklist; ++$i) {
            $c = 0;
            for ($j = 0; $j < 32; ++$j) {
                $c |= self::chrToInt($R[$j]) ^ (int) $blocklist[$i][$j];
            }
            if ($c === 0) {
                return true;
            }
        }
        return false;
    }

    




    public static function scalar_complement($s)
    {
        $t_ = self::L . str_repeat("\x00", 32);
        sodium_increment($t_);
        $s_ = $s . str_repeat("\x00", 32);
        ParagonIE_Sodium_Compat::sub($t_, $s_);
        return self::sc_reduce($t_);
    }

    



    public static function scalar_random()
    {
        do {
            $r = ParagonIE_Sodium_Compat::randombytes_buf(self::SCALAR_BYTES);
            $r[self::SCALAR_BYTES - 1] = self::intToChr(
                self::chrToInt($r[self::SCALAR_BYTES - 1]) & 0x1f
            );
        } while (
            !self::check_S_lt_L($r) || ParagonIE_Sodium_Compat::is_zero($r)
        );
        return $r;
    }

    




    public static function scalar_negate($s)
    {
        $t_ = self::L . str_repeat("\x00", 32) ;
        $s_ = $s . str_repeat("\x00", 32) ;
        ParagonIE_Sodium_Compat::sub($t_, $s_);
        return self::sc_reduce($t_);
    }

    





    public static function scalar_add($a, $b)
    {
        $a_ = $a . str_repeat("\x00", 32);
        $b_ = $b . str_repeat("\x00", 32);
        ParagonIE_Sodium_Compat::add($a_, $b_);
        return self::sc_reduce($a_);
    }

    





    public static function scalar_sub($x, $y)
    {
        $yn = self::scalar_negate($y);
        return self::scalar_add($x, $yn);
    }
}
