You are better off using Crypt::CBC when using blowfish and other similar encryption schemes, since it will setup things properly for you. Read perldoc Crypt::CBC, the first example is for using blowfish. From my experience, you need to need to properly set the "padding" for the keys and data, which CBC handles for you. From the NOTES: from perldoc Crypt::Blowfish

NOTES
       The module is capable of being used with Crypt::CBC.
       You're encouraged to read the perldoc for Crypt::CBC if
       you intend to use this module for Cipher Block Chaining
       modes.  In fact, if you have any intentions of encrypting
       more than eight bytes of data with this, or any other
       block cipher, you're going to need some type of block
       chaining help.  Crypt::CBC tends to be very good at this.
       If you're not going to encrypt more than eight bytes, your
       data must be exactly eight bytes long.  If need be, do
       your own padding. "\0" as a null byte is perfectly valid
       to use for this.  Additionally, the current maintainer for
       Crypt::Blowfish may or may not release Crypt::CBC_R which
       replaces the default 'RandomIV' initialization vector in
       Crypt::CBC with a random initialization vector.  (to the
       limits of /dev/urandom and associates)  In either case,
       ........
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