mcrypt_enc_is_block_algorithm_mode(3) php man page | unix.com

MCRYPT_ENC_IS_BLOCK_ALGORITHM_MODE(3)					 1				     MCRYPT_ENC_IS_BLOCK_ALGORITHM_MODE(3)

mcrypt_enc_is_block_algorithm_mode - Checks whether the encryption of the opened mode works on blocks

SYNOPSIS
       bool mcrypt_enc_is_block_algorithm_mode (resource  $td)

DESCRIPTION
	Tells whether the algorithm of the opened mode works on blocks (e.g.  FALSE for stream, and TRUE for cbc, cfb, ofb)..

PARAMETERS
	      o $td
		- The encryption descriptor.

RETURN VALUES
	Returns TRUE if the mode is for use with block algorithms, otherwise it returns FALSE.

PHP Documentation Group 										     MCRYPT_ENC_IS_BLOCK_ALGORITHM_MODE(3)