seed_keypair example

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

    /** * @internal You should not use this directly from another application * * @param string $pk * @param string $sk * @param string $seed * @return string * @throws SodiumException * @throws TypeError */

ParagonIE_Sodium_Core_Util::declareScalarType($seed, 'string', 1);

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_seed_keypair($seed);
        }
        if (self::use_fallback('crypto_sign_keypair')) {
            return (string) call_user_func('\\Sodium\\crypto_sign_seed_keypair', $seed);
        }
        $publicKey = '';
        $secretKey = '';
        if (PHP_INT_SIZE === 4) {
            ParagonIE_Sodium_Core32_Ed25519::seed_keypair($publicKey, $secretKey, $seed);
        } else {
            ParagonIE_Sodium_Core_Ed25519::seed_keypair($publicKey, $secretKey, $seed);
        }
        return $secretKey . $publicKey;
    }

    /** * Extract an Ed25519 public key from an Ed25519 keypair. * * @param string $keypair Keypair * @return string Public key * @throws SodiumException * @throws TypeError * @psalm-suppress MixedArgument */

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

    /** * @internal You should not use this directly from another application * * @param string $pk * @param string $sk * @param string $seed * @return string * @throws SodiumException * @throws TypeError */