Where do you see that? The version on CPAN doesn't say that at all. It simply says "Encrypts with CBC (Cypher Block Chaining)". CBC is most desirable and impossible if you split the input data in chunks of blocksize.

Update: Ah! You seem to be talking of Crypt::TEA. That's not the module the posted code is using. One should use Crypt::TEA via Crypt::CBC. It is much less secure to split the input into blocksize chunks.

Note that Crypt::TEA and Crypt::Tea cannot both be installed on a case-insensitive file system, and attempting to load one may load the other.