ParagonIE_Sodium_Core_XChaCha20::streamXorIc( string $message, string $nonce, string $key, string $ic = '' ): string

77    public static function streamXorIc($message, $nonce, $key, $ic = '')78    {79        if (self::strlen($nonce) !== 24) {80            throw new SodiumException('Nonce must be 24 bytes long');81        }82        return self::encryptBytes(83            new ParagonIE_Sodium_Core_ChaCha20_Ctx(84                self::hChaCha20(self::substr($nonce, 0, 16), $key),85                self::substr($nonce, 16, 8),86                $ic87            ),88            $message89        );90    }