mcrypt_enc_get_block_size

PHP 4 >= 4.0.2, PHP 5, PHP 7 < 7.2.0, PECL mcrypt >= 1.0.0
mcrypt_enc_get_block_size - Returns the blocksize of the opened algorithm
Manual

mcrypt_enc_get_block_size( resource$td ): int

Gets the blocksize of the opened algorithm.

Parameters

td

The encryption descriptor.

Return Values

Returns the block size of the specified algorithm in bytes.