mcrypt_module_is_block_mode Returns if the specified mode outputs blocks or not boolmcrypt_module_is_block_mode stringmode stringlib_dir This function returns &true; if the mode outputs blocks of bytes or &false; if it outputs just bytes. (e.g. &true; for cbc and ecb, and &false; for cfb and stream). The optional lib_dir parameter can contain the location where the mode module is on the system.