I'm trying to PGP-encrypt data, by importing a standard text block:

-----BEGIN PGP PUBLIC KEY BLOCK-----
data ...
-----END PGP PUBLIC KEY BLOCK-----
and then encrypting with this example code:
#!/usr/bin/perl -w
use Crypt::OpenPGP;
use Crypt::OpenPGP::KeyRing;

my($keyfile, $email) = @ARGV;
my $ring = Crypt::OpenPGP::KeyRing->new(Filename => $keyfile);
my $pgp = Crypt::OpenPGP->new(PubRing => $ring);
my $crypt = $pgp->encrypt(
    Data => 'squeamish ossifrage',
    Recipients => [ $email ],
    Armour => 1,
    Cipher => 'CAST5',
);
defined($crypt) ? print $crypt : die $pgp->errstr;

[download]

This works fine for encrypting with my colleague's key, but only after adding the Cipher => 'CAST5' - without that, his decrypt function complains of a 'bad session key'.

What I don't understand is how I can determine the appropriate cipher given the public key: I don't see anything in the Crypt::OpenPGP interface that would allow me to ask that from the KeyRing or KeyBlock objects once I've determined them.

I suspect I'm missing a fundamental concept somewhere; clues gratefully received.

Hugo

In reply to Crypt::OpenPGP - determining which cipher to use by hv

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.