Noun
blocksize (plural blocksizes)
(computing) The size of a block of data (in a file or a transmission)
If the server grants the request, the file is sent in fixed length blocks of 512 bytes by default or the number specified in the blocksize negotiated option defined by RFC 2348. Source: Internet
The blocksize has a maximum of 256 bits, but the keysize has no theoretical maximum. Source: Internet