+ # prefer AES-256, AES-192, AES-128, CAST5, 3DES:
+ my $pref_sym_algos = pack('CCCCCCC', 6, $subpacket_types->{preferred_cipher},
+ $ciphers->{aes256},
+ $ciphers->{aes192},
+ $ciphers->{aes128},
+ $ciphers->{cast5},
+ $ciphers->{tripledes}
+ );
+
+ # prefer SHA-1, SHA-256, RIPE-MD/160
+ my $pref_hash_algos = pack('CCCCC', 4, $subpacket_types->{preferred_digest},
+ $digests->{sha1},
+ $digests->{sha256},
+ $digests->{ripemd160}
+ );
+
+ # prefer ZLIB, BZip2, ZIP
+ my $pref_zip_algos = pack('CCCCC', 4, $subpacket_types->{preferred_compression},
+ $zips->{zlib},
+ $zips->{bzip2},
+ $zips->{zip}
+ );
+
+ # we support the MDC feature:
+ my $feature_subpacket = pack('CCC', 2, $subpacket_types->{features},
+ $features->{mdc});
+
+ # keyserver preference: only owner modify (???):
+ my $keyserver_pref = pack('CCC', 2, $subpacket_types->{keyserver_prefs},
+ $keyserver_prefs->{nomodify});
+
+ my $subpackets_to_be_hashed =
+ $creation_time_packet.
+ $usage_packet.
+ $expiration_packet.
+ $pref_sym_algos.
+ $pref_hash_algos.
+ $pref_zip_algos.
+ $feature_subpacket.
+ $keyserver_pref;
+
+ my $subpacket_octets = pack('n', length($subpackets_to_be_hashed));
+
+ my $sig_data_to_be_hashed =
+ $version.
+ $sigtype.
+ $pubkey_algo.
+ $hash_algo.
+ $subpacket_octets.
+ $subpackets_to_be_hashed;
+
+ my $pubkey = make_rsa_pub_key_body($rsa, $timestamp);
+ my $seckey = make_rsa_sec_key_body($rsa, $timestamp);
+
+ # this is for signing. it needs to be an old-style header with a
+ # 2-packet octet count.
+
+ my $key_data = make_packet($packet_types->{pubkey}, $pubkey, {'packet_length'=>2});
+
+ # take the last 8 bytes of the fingerprint as the keyid:
+ my $keyid = substr(fingerprint($rsa, $timestamp), 20 - 8, 8);
+
+ # the v4 signature trailer is:
+
+ # version number, literal 0xff, and then a 4-byte count of the
+ # signature data itself.
+ my $trailer = pack('CCN', 4, 0xff, length($sig_data_to_be_hashed));
+
+ my $uid_data =
+ pack('CN', 0xb4, length($uid)).
+ $uid;
+
+ my $datatosign =
+ $key_data.
+ $uid_data.
+ $sig_data_to_be_hashed.
+ $trailer;
+
+ my $data_hash = Digest::SHA1::sha1_hex($datatosign);
+
+ my $issuer_packet = pack('CCa8', 9, $subpacket_types->{issuer}, $keyid);
+
+ my $sig = Crypt::OpenSSL::Bignum->new_from_bin($rsa->sign($datatosign));
+
+ my $sig_body =
+ $sig_data_to_be_hashed.
+ pack('n', length($issuer_packet)).
+ $issuer_packet.
+ pack('n', hex(substr($data_hash, 0, 4))).
+ mpi_pack($sig);