This is Crypt::CBC version 1.0, a Perl-only implementation of the cryptographic cipher block chaining mode (CBC). In combination with a block cipher such as Crypt::DES or Crypt::IDEA, you can encrypt and decrypt messages of arbitrarily long length. The encrypted messages are compatible with the encryption format used by B. In addition to this module you will need the following: 1. MD5 Required for key and iteration vector generation. 2. Crypt::DES Required for the DES encryption algorithm. 3. Crypt::IEA Required for the IDEA encryption algorithm. You can find each of these modules on a CPAN near you. In order to get the DES and IDEA modules to compile on my system (Linux), I found I had to change a few of the #include directives. For Crypt::DES, I had to change "#include " to "#include " in the "des.h" file. For Crypt::IDEA, I had to make the same change in the file "idea.h". In addition, I had to change "#include " to "#include " in the file "idea.c". Your mileage may vary. To Install Crypt::CBC: 1. perl Makefile.PL 2. make 3. make test 4. make install Lincoln D. Stein lstein@cshl.org