ParagonIE_Sodium_Core32_Ed25519

13abstract class ParagonIE_Sodium_Core32_Ed25519 extends ParagonIE_Sodium_Core32_Curve2551914{15    const KEYPAIR_BYTES = 96;16    const SEED_BYTES = 32;17 18    /**19     * @internal You should not use this directly from another application20     *21     * @return string (96 bytes)22     * @throws Exception23     * @throws SodiumException24     * @throws TypeError25     */26    public static function keypair()27    {28        $seed = random_bytes(self::SEED_BYTES);29        $pk = '';30        $sk = '';31        self::seed_keypair($pk, $sk, $seed);32        return $sk . $pk;33    }34 35    /**36     * @internal You should not use this directly from another application37     *38     * @param string $pk39     * @param string $sk40     * @param string $seed41     * @return string42     * @throws SodiumException43     * @throws TypeError44     */45    public static function seed_keypair(&$pk, &$sk, $seed)46    {47        if (self::strlen($seed) !== self::SEED_BYTES) {48            throw new RangeException('crypto_sign keypair seed must be 32 bytes long');49        }50 51        /** @var string $pk */52        $pk = self::publickey_from_secretkey($seed);53        $sk = $seed . $pk;54        return $sk;55    }56 57    /**58     * @internal You should not use this directly from another application59     *60     * @param string $keypair61     * @return string62     * @throws TypeError63     */64    public static function secretkey($keypair)65    {66        if (self::strlen($keypair) !== self::KEYPAIR_BYTES) {67            throw new RangeException('crypto_sign keypair must be 96 bytes long');68        }69        return self::substr($keypair, 0, 64);70    }71 72    /**73     * @internal You should not use this directly from another application74     *75     * @param string $keypair76     * @return string77     * @throws RangeException78     * @throws TypeError79     */80    public static function publickey($keypair)81    {82        if (self::strlen($keypair) !== self::KEYPAIR_BYTES) {83            throw new RangeException('crypto_sign keypair must be 96 bytes long');84        }85        return self::substr($keypair, 64, 32);86    }87 88    /**89     * @internal You should not use this directly from another application90     *91     * @param string $sk92     * @return string