<?php

if (class_exists('ParagonIE_Sodium_Crypto', false)) {
    return;
}









abstract class ParagonIE_Sodium_Crypto
{
    const aead_chacha20poly1305_KEYBYTES = 32;
    const aead_chacha20poly1305_NSECBYTES = 0;
    const aead_chacha20poly1305_NPUBBYTES = 8;
    const aead_chacha20poly1305_ABYTES = 16;

    const aead_chacha20poly1305_IETF_KEYBYTES = 32;
    const aead_chacha20poly1305_IETF_NSECBYTES = 0;
    const aead_chacha20poly1305_IETF_NPUBBYTES = 12;
    const aead_chacha20poly1305_IETF_ABYTES = 16;

    const aead_xchacha20poly1305_IETF_KEYBYTES = 32;
    const aead_xchacha20poly1305_IETF_NSECBYTES = 0;
    const aead_xchacha20poly1305_IETF_NPUBBYTES = 24;
    const aead_xchacha20poly1305_IETF_ABYTES = 16;

    const box_curve25519xsalsa20poly1305_SEEDBYTES = 32;
    const box_curve25519xsalsa20poly1305_PUBLICKEYBYTES = 32;
    const box_curve25519xsalsa20poly1305_SECRETKEYBYTES = 32;
    const box_curve25519xsalsa20poly1305_BEFORENMBYTES = 32;
    const box_curve25519xsalsa20poly1305_NONCEBYTES = 24;
    const box_curve25519xsalsa20poly1305_MACBYTES = 16;
    const box_curve25519xsalsa20poly1305_BOXZEROBYTES = 16;
    const box_curve25519xsalsa20poly1305_ZEROBYTES = 32;

    const onetimeauth_poly1305_BYTES = 16;
    const onetimeauth_poly1305_KEYBYTES = 32;

    const secretbox_xsalsa20poly1305_KEYBYTES = 32;
    const secretbox_xsalsa20poly1305_NONCEBYTES = 24;
    const secretbox_xsalsa20poly1305_MACBYTES = 16;
    const secretbox_xsalsa20poly1305_BOXZEROBYTES = 16;
    const secretbox_xsalsa20poly1305_ZEROBYTES = 32;

    const secretbox_xchacha20poly1305_KEYBYTES = 32;
    const secretbox_xchacha20poly1305_NONCEBYTES = 24;
    const secretbox_xchacha20poly1305_MACBYTES = 16;
    const secretbox_xchacha20poly1305_BOXZEROBYTES = 16;
    const secretbox_xchacha20poly1305_ZEROBYTES = 32;

    const stream_salsa20_KEYBYTES = 32;

    












    public static function aead_chacha20poly1305_decrypt(
        $message = '',
        $ad = '',
        $nonce = '',
        $key = ''
    ) {
         
        $len = ParagonIE_Sodium_Core_Util::strlen($message);

         
        $clen = $len - self::aead_chacha20poly1305_ABYTES;

         
        $adlen = ParagonIE_Sodium_Core_Util::strlen($ad);

         
        $mac = ParagonIE_Sodium_Core_Util::substr(
            $message,
            $clen,
            self::aead_chacha20poly1305_ABYTES
        );

         
        $ciphertext = ParagonIE_Sodium_Core_Util::substr($message, 0, $clen);

         
        $block0 = ParagonIE_Sodium_Core_ChaCha20::stream(
            32,
            $nonce,
            $key
        );

         
        $state = new ParagonIE_Sodium_Core_Poly1305_State($block0);
        try {
            ParagonIE_Sodium_Compat::memzero($block0);
        } catch (SodiumException $ex) {
            $block0 = null;
        }
        $state->update($ad);
        $state->update(ParagonIE_Sodium_Core_Util::store64_le($adlen));
        $state->update($ciphertext);
        $state->update(ParagonIE_Sodium_Core_Util::store64_le($clen));
        $computed_mac = $state->finish();

         
        if (!ParagonIE_Sodium_Core_Util::verify_16($computed_mac, $mac)) {
            throw new SodiumException('Invalid MAC');
        }

         
        return ParagonIE_Sodium_Core_ChaCha20::streamXorIc(
            $ciphertext,
            $nonce,
            $key,
            ParagonIE_Sodium_Core_Util::store64_le(1)
        );
    }

    












    public static function aead_chacha20poly1305_encrypt(
        $message = '',
        $ad = '',
        $nonce = '',
        $key = ''
    ) {
         
        $len = ParagonIE_Sodium_Core_Util::strlen($message);

         
        $adlen = ParagonIE_Sodium_Core_Util::strlen($ad);

         
        $block0 = ParagonIE_Sodium_Core_ChaCha20::stream(
            32,
            $nonce,
            $key
        );
        $state = new ParagonIE_Sodium_Core_Poly1305_State($block0);
        try {
            ParagonIE_Sodium_Compat::memzero($block0);
        } catch (SodiumException $ex) {
            $block0 = null;
        }

         
        $ciphertext = ParagonIE_Sodium_Core_ChaCha20::streamXorIc(
            $message,
            $nonce,
            $key,
            ParagonIE_Sodium_Core_Util::store64_le(1)
        );

        $state->update($ad);
        $state->update(ParagonIE_Sodium_Core_Util::store64_le($adlen));
        $state->update($ciphertext);
        $state->update(ParagonIE_Sodium_Core_Util::store64_le($len));
        return $ciphertext . $state->finish();
    }

    












    public static function aead_chacha20poly1305_ietf_decrypt(
        $message = '',
        $ad = '',
        $nonce = '',
        $key = ''
    ) {
         
        $adlen = ParagonIE_Sodium_Core_Util::strlen($ad);

         
        $len = ParagonIE_Sodium_Core_Util::strlen($message);

         
        $clen = $len - self::aead_chacha20poly1305_IETF_ABYTES;

         
        $block0 = ParagonIE_Sodium_Core_ChaCha20::ietfStream(
            32,
            $nonce,
            $key
        );

         
        $mac = ParagonIE_Sodium_Core_Util::substr(
            $message,
            $len - self::aead_chacha20poly1305_IETF_ABYTES,
            self::aead_chacha20poly1305_IETF_ABYTES
        );

         
        $ciphertext = ParagonIE_Sodium_Core_Util::substr(
            $message,
            0,
            $len - self::aead_chacha20poly1305_IETF_ABYTES
        );

         
        $state = new ParagonIE_Sodium_Core_Poly1305_State($block0);
        try {
            ParagonIE_Sodium_Compat::memzero($block0);
        } catch (SodiumException $ex) {
            $block0 = null;
        }
        $state->update($ad);
        $state->update(str_repeat("\x00", ((0x10 - $adlen) & 0xf)));
        $state->update($ciphertext);
        $state->update(str_repeat("\x00", (0x10 - $clen) & 0xf));
        $state->update(ParagonIE_Sodium_Core_Util::store64_le($adlen));
        $state->update(ParagonIE_Sodium_Core_Util::store64_le($clen));
        $computed_mac = $state->finish();

         
        if (!ParagonIE_Sodium_Core_Util::verify_16($computed_mac, $mac)) {
            throw new SodiumException('Invalid MAC');
        }

         
        return ParagonIE_Sodium_Core_ChaCha20::ietfStreamXorIc(
            $ciphertext,
            $nonce,
            $key,
            ParagonIE_Sodium_Core_Util::store64_le(1)
        );
    }

    












    public static function aead_chacha20poly1305_ietf_encrypt(
        $message = '',
        $ad = '',
        $nonce = '',
        $key = ''
    ) {
         
        $len = ParagonIE_Sodium_Core_Util::strlen($message);

         
        $adlen = ParagonIE_Sodium_Core_Util::strlen($ad);

         
        $block0 = ParagonIE_Sodium_Core_ChaCha20::ietfStream(
            32,
            $nonce,
            $key
        );
        $state = new ParagonIE_Sodium_Core_Poly1305_State($block0);
        try {
            ParagonIE_Sodium_Compat::memzero($block0);
        } catch (SodiumException $ex) {
            $block0 = null;
        }

         
        $ciphertext = ParagonIE_Sodium_Core_ChaCha20::ietfStreamXorIc(
            $message,
            $nonce,
            $key,
            ParagonIE_Sodium_Core_Util::store64_le(1)
        );

        $state->update($ad);
        $state->update(str_repeat("\x00", ((0x10 - $adlen) & 0xf)));
        $state->update($ciphertext);
        $state->update(str_repeat("\x00", ((0x10 - $len) & 0xf)));
        $state->update(ParagonIE_Sodium_Core_Util::store64_le($adlen));
        $state->update(ParagonIE_Sodium_Core_Util::store64_le($len));
        return $ciphertext . $state->finish();
    }

    












    public static function aead_xchacha20poly1305_ietf_decrypt(
        $message = '',
        $ad = '',
        $nonce = '',
        $key = ''
    ) {
        $subkey = ParagonIE_Sodium_Core_HChaCha20::hChaCha20(
            ParagonIE_Sodium_Core_Util::substr($nonce, 0, 16),
            $key
        );
        $nonceLast = "\x00\x00\x00\x00" .
            ParagonIE_Sodium_Core_Util::substr($nonce, 16, 8);

        return self::aead_chacha20poly1305_ietf_decrypt($message, $ad, $nonceLast, $subkey);
    }

    












    public static function aead_xchacha20poly1305_ietf_encrypt(
        $message = '',
        $ad = '',
        $nonce = '',
        $key = ''
    ) {
        $subkey = ParagonIE_Sodium_Core_HChaCha20::hChaCha20(
            ParagonIE_Sodium_Core_Util::substr($nonce, 0, 16),
            $key
        );
        $nonceLast = "\x00\x00\x00\x00" .
            ParagonIE_Sodium_Core_Util::substr($nonce, 16, 8);

        return self::aead_chacha20poly1305_ietf_encrypt($message, $ad, $nonceLast, $subkey);
    }

    









    public static function auth($message, $key)
    {
        return ParagonIE_Sodium_Core_Util::substr(
            hash_hmac('sha512', $message, $key, true),
            0,
            32
        );
    }

    











    public static function auth_verify($mac, $message, $key)
    {
        return ParagonIE_Sodium_Core_Util::hashEquals(
            $mac,
            self::auth($message, $key)
        );
    }

    











    public static function box($plaintext, $nonce, $keypair)
    {
        $c = self::secretbox(
            $plaintext,
            $nonce,
            self::box_beforenm(
                self::box_secretkey($keypair),
                self::box_publickey($keypair)
            )
        );
        return $c;
    }

    










    public static function box_seal($message, $publicKey)
    {
         
        $ephemeralKeypair = self::box_keypair();

         
        $ephemeralSK = self::box_secretkey($ephemeralKeypair);

         
        $ephemeralPK = self::box_publickey($ephemeralKeypair);

         
        $nonce = self::generichash(
            $ephemeralPK . $publicKey,
            '',
            24
        );

         
        $keypair = self::box_keypair_from_secretkey_and_publickey($ephemeralSK, $publicKey);

         
        $ciphertext = self::box($message, $nonce, $keypair);
        try {
            ParagonIE_Sodium_Compat::memzero($ephemeralKeypair);
            ParagonIE_Sodium_Compat::memzero($ephemeralSK);
            ParagonIE_Sodium_Compat::memzero($nonce);
        } catch (SodiumException $ex) {
            $ephemeralKeypair = null;
            $ephemeralSK = null;
            $nonce = null;
        }
        return $ephemeralPK . $ciphertext;
    }

    










    public static function box_seal_open($message, $keypair)
    {
         
        $ephemeralPK = ParagonIE_Sodium_Core_Util::substr($message, 0, 32);

         
        $ciphertext = ParagonIE_Sodium_Core_Util::substr($message, 32);

         
        $secretKey = self::box_secretkey($keypair);

         
        $publicKey = self::box_publickey($keypair);

         
        $nonce = self::generichash(
            $ephemeralPK . $publicKey,
            '',
            24
        );

         
        $keypair = self::box_keypair_from_secretkey_and_publickey($secretKey, $ephemeralPK);

         
        $m = self::box_open($ciphertext, $nonce, $keypair);
        try {
            ParagonIE_Sodium_Compat::memzero($secretKey);
            ParagonIE_Sodium_Compat::memzero($ephemeralPK);
            ParagonIE_Sodium_Compat::memzero($nonce);
        } catch (SodiumException $ex) {
            $secretKey = null;
            $ephemeralPK = null;
            $nonce = null;
        }
        return $m;
    }

    










    public static function box_beforenm($sk, $pk)
    {
        return ParagonIE_Sodium_Core_HSalsa20::hsalsa20(
            str_repeat("\x00", 16),
            self::scalarmult($sk, $pk)
        );
    }

    







    public static function box_keypair()
    {
        $sKey = random_bytes(32);
        $pKey = self::scalarmult_base($sKey);
        return $sKey . $pKey;
    }

    





    public static function box_seed_keypair($seed)
    {
        $sKey = ParagonIE_Sodium_Core_Util::substr(
            hash('sha512', $seed, true),
            0,
            32
        );
        $pKey = self::scalarmult_base($sKey);
        return $sKey . $pKey;
    }

    







    public static function box_keypair_from_secretkey_and_publickey($sKey, $pKey)
    {
        return ParagonIE_Sodium_Core_Util::substr($sKey, 0, 32) .
            ParagonIE_Sodium_Core_Util::substr($pKey, 0, 32);
    }

    







    public static function box_secretkey($keypair)
    {
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== 64) {
            throw new RangeException(
                'Must be ParagonIE_Sodium_Compat::CRYPTO_BOX_KEYPAIRBYTES bytes long.'
            );
        }
        return ParagonIE_Sodium_Core_Util::substr($keypair, 0, 32);
    }

    







    public static function box_publickey($keypair)
    {
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== ParagonIE_Sodium_Compat::CRYPTO_BOX_KEYPAIRBYTES) {
            throw new RangeException(
                'Must be ParagonIE_Sodium_Compat::CRYPTO_BOX_KEYPAIRBYTES bytes long.'
            );
        }
        return ParagonIE_Sodium_Core_Util::substr($keypair, 32, 32);
    }

    








    public static function box_publickey_from_secretkey($sKey)
    {
        if (ParagonIE_Sodium_Core_Util::strlen($sKey) !== ParagonIE_Sodium_Compat::CRYPTO_BOX_SECRETKEYBYTES) {
            throw new RangeException(
                'Must be ParagonIE_Sodium_Compat::CRYPTO_BOX_SECRETKEYBYTES bytes long.'
            );
        }
        return self::scalarmult_base($sKey);
    }

    











    public static function box_open($ciphertext, $nonce, $keypair)
    {
        return self::secretbox_open(
            $ciphertext,
            $nonce,
            self::box_beforenm(
                self::box_secretkey($keypair),
                self::box_publickey($keypair)
            )
        );
    }

    












    public static function generichash($message, $key = '', $outlen = 32)
    {
         
        ParagonIE_Sodium_Core_BLAKE2b::pseudoConstructor();

        $k = null;
        if (!empty($key)) {
             
            $k = ParagonIE_Sodium_Core_BLAKE2b::stringToSplFixedArray($key);
            if ($k->count() > ParagonIE_Sodium_Core_BLAKE2b::KEYBYTES) {
                throw new RangeException('Invalid key size');
            }
        }

         
        $in = ParagonIE_Sodium_Core_BLAKE2b::stringToSplFixedArray($message);

         
        $ctx = ParagonIE_Sodium_Core_BLAKE2b::init($k, $outlen);
        ParagonIE_Sodium_Core_BLAKE2b::update($ctx, $in, $in->count());

         
        $out = new SplFixedArray($outlen);
        $out = ParagonIE_Sodium_Core_BLAKE2b::finish($ctx, $out);

         
        $outArray = $out->toArray();
        return ParagonIE_Sodium_Core_Util::intArrayToString($outArray);
    }

    










    public static function generichash_final($ctx, $outlen = 32)
    {
        if (!is_string($ctx)) {
            throw new TypeError('Context must be a string');
        }
        $out = new SplFixedArray($outlen);

         
        $context = ParagonIE_Sodium_Core_BLAKE2b::stringToContext($ctx);

         
        $out = ParagonIE_Sodium_Core_BLAKE2b::finish($context, $out);

         
        $outArray = $out->toArray();
        return ParagonIE_Sodium_Core_Util::intArrayToString($outArray);
    }

    











    public static function generichash_init($key = '', $outputLength = 32)
    {
         
        ParagonIE_Sodium_Core_BLAKE2b::pseudoConstructor();

        $k = null;
        if (!empty($key)) {
            $k = ParagonIE_Sodium_Core_BLAKE2b::stringToSplFixedArray($key);
            if ($k->count() > ParagonIE_Sodium_Core_BLAKE2b::KEYBYTES) {
                throw new RangeException('Invalid key size');
            }
        }

         
        $ctx = ParagonIE_Sodium_Core_BLAKE2b::init($k, $outputLength);

        return ParagonIE_Sodium_Core_BLAKE2b::contextToString($ctx);
    }

    













    public static function generichash_init_salt_personal(
        $key = '',
        $outputLength = 32,
        $salt = '',
        $personal = ''
    ) {
         
        ParagonIE_Sodium_Core_BLAKE2b::pseudoConstructor();

        $k = null;
        if (!empty($key)) {
            $k = ParagonIE_Sodium_Core_BLAKE2b::stringToSplFixedArray($key);
            if ($k->count() > ParagonIE_Sodium_Core_BLAKE2b::KEYBYTES) {
                throw new RangeException('Invalid key size');
            }
        }
        if (!empty($salt)) {
            $s = ParagonIE_Sodium_Core_BLAKE2b::stringToSplFixedArray($salt);
        } else {
            $s = null;
        }
        if (!empty($salt)) {
            $p = ParagonIE_Sodium_Core_BLAKE2b::stringToSplFixedArray($personal);
        } else {
            $p = null;
        }

         
        $ctx = ParagonIE_Sodium_Core_BLAKE2b::init($k, $outputLength, $s, $p);

        return ParagonIE_Sodium_Core_BLAKE2b::contextToString($ctx);
    }

    










    public static function generichash_update($ctx, $message)
    {
         
        ParagonIE_Sodium_Core_BLAKE2b::pseudoConstructor();

         
        $context = ParagonIE_Sodium_Core_BLAKE2b::stringToContext($ctx);

         
        $in = ParagonIE_Sodium_Core_BLAKE2b::stringToSplFixedArray($message);

        ParagonIE_Sodium_Core_BLAKE2b::update($context, $in, $in->count());

        return ParagonIE_Sodium_Core_BLAKE2b::contextToString($context);
    }

    












    public static function keyExchange($my_sk, $their_pk, $client_pk, $server_pk)
    {
        return ParagonIE_Sodium_Compat::crypto_generichash(
            ParagonIE_Sodium_Compat::crypto_scalarmult($my_sk, $their_pk) .
            $client_pk .
            $server_pk
        );
    }

    











    public static function scalarmult($sKey, $pKey)
    {
        $q = ParagonIE_Sodium_Core_X25519::crypto_scalarmult_curve25519_ref10($sKey, $pKey);
        self::scalarmult_throw_if_zero($q);
        return $q;
    }

    









    public static function scalarmult_base($secret)
    {
        $q = ParagonIE_Sodium_Core_X25519::crypto_scalarmult_curve25519_ref10_base($secret);
        self::scalarmult_throw_if_zero($q);
        return $q;
    }

    







    protected static function scalarmult_throw_if_zero($q)
    {
        $d = 0;
        for ($i = 0; $i < self::box_curve25519xsalsa20poly1305_SECRETKEYBYTES; ++$i) {
            $d |= ParagonIE_Sodium_Core_Util::chrToInt($q[$i]);
        }

         
        if (-(1 & (($d - 1) >> 8))) {
            throw new SodiumException('Zero public key is not allowed');
        }
    }

    











    public static function secretbox($plaintext, $nonce, $key)
    {
         
        $subkey = ParagonIE_Sodium_Core_HSalsa20::hsalsa20($nonce, $key);

         
        $block0 = str_repeat("\x00", 32);

         
        $mlen = ParagonIE_Sodium_Core_Util::strlen($plaintext);
        $mlen0 = $mlen;
        if ($mlen0 > 64 - self::secretbox_xsalsa20poly1305_ZEROBYTES) {
            $mlen0 = 64 - self::secretbox_xsalsa20poly1305_ZEROBYTES;
        }
        $block0 .= ParagonIE_Sodium_Core_Util::substr($plaintext, 0, $mlen0);

         
        $block0 = ParagonIE_Sodium_Core_Salsa20::salsa20_xor(
            $block0,
            ParagonIE_Sodium_Core_Util::substr($nonce, 16, 8),
            $subkey
        );

         
        $c = ParagonIE_Sodium_Core_Util::substr(
            $block0,
            self::secretbox_xsalsa20poly1305_ZEROBYTES
        );
        if ($mlen > $mlen0) {
            $c .= ParagonIE_Sodium_Core_Salsa20::salsa20_xor_ic(
                ParagonIE_Sodium_Core_Util::substr(
                    $plaintext,
                    self::secretbox_xsalsa20poly1305_ZEROBYTES
                ),
                ParagonIE_Sodium_Core_Util::substr($nonce, 16, 8),
                1,
                $subkey
            );
        }
        $state = new ParagonIE_Sodium_Core_Poly1305_State(
            ParagonIE_Sodium_Core_Util::substr(
                $block0,
                0,
                self::onetimeauth_poly1305_KEYBYTES
            )
        );
        try {
            ParagonIE_Sodium_Compat::memzero($block0);
            ParagonIE_Sodium_Compat::memzero($subkey);
        } catch (SodiumException $ex) {
            $block0 = null;
            $subkey = null;
        }

        $state->update($c);

         
        $c = $state->finish() . $c;
        unset($state);

        return $c;
    }

    











    public static function secretbox_open($ciphertext, $nonce, $key)
    {
         
        $mac = ParagonIE_Sodium_Core_Util::substr(
            $ciphertext,
            0,
            self::secretbox_xsalsa20poly1305_MACBYTES
        );

         
        $c = ParagonIE_Sodium_Core_Util::substr(
            $ciphertext,
            self::secretbox_xsalsa20poly1305_MACBYTES
        );

         
        $clen = ParagonIE_Sodium_Core_Util::strlen($c);

         
        $subkey = ParagonIE_Sodium_Core_HSalsa20::hsalsa20($nonce, $key);

         
        $block0 = ParagonIE_Sodium_Core_Salsa20::salsa20(
            64,
            ParagonIE_Sodium_Core_Util::substr($nonce, 16, 8),
            $subkey
        );
        $verified = ParagonIE_Sodium_Core_Poly1305::onetimeauth_verify(
            $mac,
            $c,
            ParagonIE_Sodium_Core_Util::substr($block0, 0, 32)
        );
        if (!$verified) {
            try {
                ParagonIE_Sodium_Compat::memzero($subkey);
            } catch (SodiumException $ex) {
                $subkey = null;
            }
            throw new SodiumException('Invalid MAC');
        }

         
        $m = ParagonIE_Sodium_Core_Util::xorStrings(
            ParagonIE_Sodium_Core_Util::substr($block0, self::secretbox_xsalsa20poly1305_ZEROBYTES),
            ParagonIE_Sodium_Core_Util::substr($c, 0, self::secretbox_xsalsa20poly1305_ZEROBYTES)
        );
        if ($clen > self::secretbox_xsalsa20poly1305_ZEROBYTES) {
             
            $m .= ParagonIE_Sodium_Core_Salsa20::salsa20_xor_ic(
                ParagonIE_Sodium_Core_Util::substr(
                    $c,
                    self::secretbox_xsalsa20poly1305_ZEROBYTES
                ),
                ParagonIE_Sodium_Core_Util::substr($nonce, 16, 8),
                1,
                (string) $subkey
            );
        }
        return $m;
    }

    











    public static function secretbox_xchacha20poly1305($plaintext, $nonce, $key)
    {
         
        $subkey = ParagonIE_Sodium_Core_HChaCha20::hChaCha20(
            ParagonIE_Sodium_Core_Util::substr($nonce, 0, 16),
            $key
        );
        $nonceLast = ParagonIE_Sodium_Core_Util::substr($nonce, 16, 8);

         
        $block0 = str_repeat("\x00", 32);

         
        $mlen = ParagonIE_Sodium_Core_Util::strlen($plaintext);
        $mlen0 = $mlen;
        if ($mlen0 > 64 - self::secretbox_xchacha20poly1305_ZEROBYTES) {
            $mlen0 = 64 - self::secretbox_xchacha20poly1305_ZEROBYTES;
        }
        $block0 .= ParagonIE_Sodium_Core_Util::substr($plaintext, 0, $mlen0);

         
        $block0 = ParagonIE_Sodium_Core_ChaCha20::streamXorIc(
            $block0,
            $nonceLast,
            $subkey
        );

         
        $c = ParagonIE_Sodium_Core_Util::substr(
            $block0,
            self::secretbox_xchacha20poly1305_ZEROBYTES
        );
        if ($mlen > $mlen0) {
            $c .= ParagonIE_Sodium_Core_ChaCha20::streamXorIc(
                ParagonIE_Sodium_Core_Util::substr(
                    $plaintext,
                    self::secretbox_xchacha20poly1305_ZEROBYTES
                ),
                $nonceLast,
                $subkey,
                ParagonIE_Sodium_Core_Util::store64_le(1)
            );
        }
        $state = new ParagonIE_Sodium_Core_Poly1305_State(
            ParagonIE_Sodium_Core_Util::substr(
                $block0,
                0,
                self::onetimeauth_poly1305_KEYBYTES
            )
        );
        try {
            ParagonIE_Sodium_Compat::memzero($block0);
            ParagonIE_Sodium_Compat::memzero($subkey);
        } catch (SodiumException $ex) {
            $block0 = null;
            $subkey = null;
        }

        $state->update($c);

         
        $c = $state->finish() . $c;
        unset($state);

        return $c;
    }

    











    public static function secretbox_xchacha20poly1305_open($ciphertext, $nonce, $key)
    {
         
        $mac = ParagonIE_Sodium_Core_Util::substr(
            $ciphertext,
            0,
            self::secretbox_xchacha20poly1305_MACBYTES
        );

         
        $c = ParagonIE_Sodium_Core_Util::substr(
            $ciphertext,
            self::secretbox_xchacha20poly1305_MACBYTES
        );

         
        $clen = ParagonIE_Sodium_Core_Util::strlen($c);

         
        $subkey = ParagonIE_Sodium_Core_HChaCha20::hchacha20(
            ParagonIE_Sodium_Core_Util::substr($nonce, 0, 16),
            $key
        );

         
        $block0 = ParagonIE_Sodium_Core_ChaCha20::stream(
            64,
            ParagonIE_Sodium_Core_Util::substr($nonce, 16, 8),
            $subkey
        );
        $verified = ParagonIE_Sodium_Core_Poly1305::onetimeauth_verify(
            $mac,
            $c,
            ParagonIE_Sodium_Core_Util::substr($block0, 0, 32)
        );

        if (!$verified) {
            try {
                ParagonIE_Sodium_Compat::memzero($subkey);
            } catch (SodiumException $ex) {
                $subkey = null;
            }
            throw new SodiumException('Invalid MAC');
        }

         
        $m = ParagonIE_Sodium_Core_Util::xorStrings(
            ParagonIE_Sodium_Core_Util::substr($block0, self::secretbox_xchacha20poly1305_ZEROBYTES),
            ParagonIE_Sodium_Core_Util::substr($c, 0, self::secretbox_xchacha20poly1305_ZEROBYTES)
        );

        if ($clen > self::secretbox_xchacha20poly1305_ZEROBYTES) {
             
            $m .= ParagonIE_Sodium_Core_ChaCha20::streamXorIc(
                ParagonIE_Sodium_Core_Util::substr(
                    $c,
                    self::secretbox_xchacha20poly1305_ZEROBYTES
                ),
                ParagonIE_Sodium_Core_Util::substr($nonce, 16, 8),
                (string) $subkey,
                ParagonIE_Sodium_Core_Util::store64_le(1)
            );
        }
        return $m;
    }

    





    public static function secretstream_xchacha20poly1305_init_push($key)
    {
         
        $out = random_bytes(24);

         
        $subkey = ParagonIE_Sodium_Core_HChaCha20::hChaCha20(
            ParagonIE_Sodium_Core_Util::substr($out, 0, 16),
            $key
        );
        $state = new ParagonIE_Sodium_Core_SecretStream_State(
            $subkey,
            ParagonIE_Sodium_Core_Util::substr($out, 16, 8) . str_repeat("\0", 4)
        );

         
        $state->counterReset();

         
         
         
        return array(
            $state->toString(),
            $out
        );
    }

    





    public static function secretstream_xchacha20poly1305_init_pull($key, $header)
    {
         
        $subkey = ParagonIE_Sodium_Core_HChaCha20::hChaCha20(
            ParagonIE_Sodium_Core_Util::substr($header, 0, 16),
            $key
        );
        $state = new ParagonIE_Sodium_Core_SecretStream_State(
            $subkey,
            ParagonIE_Sodium_Core_Util::substr($header, 16)
        );
        $state->counterReset();
         
         
         
         
        return $state->toString();
    }

    







    public static function secretstream_xchacha20poly1305_push(&$state, $msg, $aad = '', $tag = 0)
    {
        $st = ParagonIE_Sodium_Core_SecretStream_State::fromString($state);
         
         
         
         
         

        $msglen = ParagonIE_Sodium_Core_Util::strlen($msg);
        $aadlen = ParagonIE_Sodium_Core_Util::strlen($aad);

        if ((($msglen + 63) >> 6) > 0xfffffffe) {
            throw new SodiumException(
                'message cannot be larger than SODIUM_CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_MESSAGEBYTES_MAX bytes'
            );
        }

         
         
         
         
         
         

         
         
         
        $auth = new ParagonIE_Sodium_Core_Poly1305_State(
            ParagonIE_Sodium_Core_ChaCha20::ietfStream(32, $st->getCombinedNonce(), $st->getKey())
        );

         
        $auth->update($aad);

         
         
        $auth->update(str_repeat("\0", ((0x10 - $aadlen) & 0xf)));

         
         
         
         
        $block = ParagonIE_Sodium_Core_ChaCha20::ietfStreamXorIc(
            ParagonIE_Sodium_Core_Util::intToChr($tag) . str_repeat("\0", 63),
            $st->getCombinedNonce(),
            $st->getKey(),
            ParagonIE_Sodium_Core_Util::store64_le(1)
        );

         
        $auth->update($block);

         
        $out = $block[0];
         
         
        $cipher = ParagonIE_Sodium_Core_ChaCha20::ietfStreamXorIc(
            $msg,
            $st->getCombinedNonce(),
            $st->getKey(),
            ParagonIE_Sodium_Core_Util::store64_le(2)
        );

         
        $auth->update($cipher);

        $out .= $cipher;
        unset($cipher);

         
         
        $auth->update(str_repeat("\0", ((0x10 - 64 + $msglen) & 0xf)));

         
        $slen = ParagonIE_Sodium_Core_Util::store64_le($aadlen);

         
        $auth->update($slen);

         
        $slen = ParagonIE_Sodium_Core_Util::store64_le(64 + $msglen);

         
        $auth->update($slen);

         
         
        $mac = $auth->finish();
        $out .= $mac;

         
        unset($auth);


         
         
        $st->xorNonce($mac);

         
         
        $st->incrementCounter();
         
        $state = $st->toString();

         
        $rekey = ($tag & ParagonIE_Sodium_Compat::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_REKEY) !== 0;
         
         
         
         
         
        if ($rekey || $st->needsRekey()) {
             
            self::secretstream_xchacha20poly1305_rekey($state);
        }
         
         
         
        return $out;
    }

    






    public static function secretstream_xchacha20poly1305_pull(&$state, $cipher, $aad = '')
    {
        $st = ParagonIE_Sodium_Core_SecretStream_State::fromString($state);

        $cipherlen = ParagonIE_Sodium_Core_Util::strlen($cipher);
         
        $msglen = $cipherlen - ParagonIE_Sodium_Compat::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_ABYTES;
        $aadlen = ParagonIE_Sodium_Core_Util::strlen($aad);

         
         
         
        if ((($msglen + 63) >> 6) > 0xfffffffe) {
            throw new SodiumException(
                'message cannot be larger than SODIUM_CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_MESSAGEBYTES_MAX bytes'
            );
        }

         
         
         
        $auth = new ParagonIE_Sodium_Core_Poly1305_State(
            ParagonIE_Sodium_Core_ChaCha20::ietfStream(32, $st->getCombinedNonce(), $st->getKey())
        );

         
        $auth->update($aad);

         
         
        $auth->update(str_repeat("\0", ((0x10 - $aadlen) & 0xf)));


         
         
         
         
        $block = ParagonIE_Sodium_Core_ChaCha20::ietfStreamXorIc(
            $cipher[0] . str_repeat("\0", 63),
            $st->getCombinedNonce(),
            $st->getKey(),
            ParagonIE_Sodium_Core_Util::store64_le(1)
        );
         
         
         
        $tag = ParagonIE_Sodium_Core_Util::chrToInt($block[0]);
        $block[0] = $cipher[0];
        $auth->update($block);


         
         
        $auth->update(ParagonIE_Sodium_Core_Util::substr($cipher, 1, $msglen));

         
         
        $auth->update(str_repeat("\0", ((0x10 - 64 + $msglen) & 0xf)));

         
         
        $slen = ParagonIE_Sodium_Core_Util::store64_le($aadlen);
        $auth->update($slen);

         
         
        $slen = ParagonIE_Sodium_Core_Util::store64_le(64 + $msglen);
        $auth->update($slen);

         
         
        $mac = $auth->finish();

         
         
         
         
         

        $stored = ParagonIE_Sodium_Core_Util::substr($cipher, $msglen + 1, 16);
        if (!ParagonIE_Sodium_Core_Util::hashEquals($mac, $stored)) {
            return false;
        }

         
        $out = ParagonIE_Sodium_Core_ChaCha20::ietfStreamXorIc(
            ParagonIE_Sodium_Core_Util::substr($cipher, 1, $msglen),
            $st->getCombinedNonce(),
            $st->getKey(),
            ParagonIE_Sodium_Core_Util::store64_le(2)
        );

         
         
        $st->xorNonce($mac);

         
         
        $st->incrementCounter();

         
         
         
         
         

         
        $state = $st->toString();

         
        $rekey = ($tag & ParagonIE_Sodium_Compat::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_REKEY) !== 0;
        if ($rekey || $st->needsRekey()) {
             
            self::secretstream_xchacha20poly1305_rekey($state);
        }
        return array($out, $tag);
    }

    




    public static function secretstream_xchacha20poly1305_rekey(&$state)
    {
        $st = ParagonIE_Sodium_Core_SecretStream_State::fromString($state);
         
         
         
         
         
         
        $new_key_and_inonce = $st->getKey();

         
         
         
         
        $new_key_and_inonce .= ParagonIE_Sodium_Core_Util::substR($st->getNonce(), 0, 8);

         
         
         

        $st->rekey(ParagonIE_Sodium_Core_ChaCha20::ietfStreamXorIc(
            $new_key_and_inonce,
            $st->getCombinedNonce(),
            $st->getKey(),
            ParagonIE_Sodium_Core_Util::store64_le(0)
        ));

         
         
         
         
         
         
         
         
        $st->counterReset();

        $state = $st->toString();
    }

    










    public static function sign_detached($message, $sk)
    {
        return ParagonIE_Sodium_Core_Ed25519::sign_detached($message, $sk);
    }

    










    public static function sign($message, $sk)
    {
        return ParagonIE_Sodium_Core_Ed25519::sign($message, $sk);
    }

    










    public static function sign_open($signedMessage, $pk)
    {
        return ParagonIE_Sodium_Core_Ed25519::sign_open($signedMessage, $pk);
    }

    











    public static function sign_verify_detached($signature, $message, $pk)
    {
        return ParagonIE_Sodium_Core_Ed25519::verify_detached($signature, $message, $pk);
    }
}
