maximum passphrase for symmetric encryption ?

[vedaal at nym.hush.com]

Jerome Baum jerome at jeromebaum.com wrote on
Tue Dec 27 23:23:50 CET 2011 :

>gpg might cut off after the 64th character and drop entropy from 
your >passphrase. But that sounds unlikely.


That's exactly my question.
Does gnupg have a maximum string length for a passphrase, and 
restrict itself to the entropy contained within that length?

(Apparently not.)

I tried symmetrically encrypting, using a string of 65 characters, 
and it works, and requires exactly those 65 characters to decrypt. 
(Substituting any other character for the 65th character does not 
decrypt).

Curious as to why Truecrypt does not accept more than 64, for whole 
disk encryption.


vedaal