pem2openpgp: replace raw numbers with semantic labelling to make it more readable.
[monkeysphere.git] / src / keytrans / pem2openpgp
index e76ba6f81e36c02db87426262d1450fda5b9d867..637eba2a225fecbc399a64e3ad6433461b63a36c 100755 (executable)
@@ -114,17 +114,17 @@ sub fingerprint {
 my $asym_algos = { rsa => 1,
                   elgamal => 16,
                   dsa => 17,
-                  }
+                  };
 
 # see RFC 4880 section 9.2
 my $ciphers = { plaintext => 0,
                idea => 1,
-               3des => 2,
+               tripledes => 2,
                cast5 => 3,
                blowfish => 4,
                aes128 => 7,
                aes192 => 8,
-               aes256 => 9
+               aes256 => 9,
                twofish => 10,
              };
 
@@ -156,7 +156,6 @@ my $usage_flags = { certify => 0x01,
                    shared => 0x80, # more than one person holds the entire private key
                  };
 
-
 # see RFC 4880 section 4.3
 my $packet_types = { pubkey_enc_session => 1,
                     sig => 2,
@@ -197,30 +196,39 @@ my $sig_types = { binary_doc => 0x00,
 
 
 # see RFC 4880 section 5.2.3.1
-my $subpacket_types => { sig_creation_time => 2,
-                        sig_expiration_time => 3,
-                        exportable => 4,
-                        trust_sig => 5,
-                        regex => 6,
-                        revocable => 7,
-                        key_expiration_time => 9,
-                        preferred_cipher => 11,
-                        revocation_key => 12,
-                        issuer => 16,
-                        notation => 20,
-                        preferred_digest => 21,
-                        keyserver_prefs => 23,
-                        preferred_keyserver => 24,
-                        primary_uid => 25,
-                        policy_uri => 26,
-                        usage_flags => 27,
-                        signers_uid => 28,
-                        revocation_reason => 29,
-                        features => 30,
-                        signature_target => 31,
-                        embedded_signature = 32,
+my $subpacket_types = { sig_creation_time => 2,
+                       sig_expiration_time => 3,
+                       exportable => 4,
+                       trust_sig => 5,
+                       regex => 6,
+                       revocable => 7,
+                       key_expiration_time => 9,
+                       preferred_cipher => 11,
+                       revocation_key => 12,
+                       issuer => 16,
+                       notation => 20,
+                       preferred_digest => 21,
+                       preferred_compression => 22,
+                       keyserver_prefs => 23,
+                       preferred_keyserver => 24,
+                       primary_uid => 25,
+                       policy_uri => 26,
+                       usage_flags => 27,
+                       signers_uid => 28,
+                       revocation_reason => 29,
+                       features => 30,
+                       signature_target => 31,
+                       embedded_signature => 32,
                       };
 
+# bitstring (see RFC 4880 section 5.2.3.24)
+my $features = { mdc => 0x01
+              };
+
+# bitstring (see RFC 4880 5.2.3.17)
+my $keyserver_prefs = { nomodify => 0x80
+                     };
+
 # we're just not dealing with newline business right now.  slurp in
 # the whole file.
 undef $/;
@@ -230,7 +238,10 @@ my $buf = <STDIN>;
 my $rsa = Crypt::OpenSSL::RSA->new_private_key($buf);
 
 $rsa->use_sha1_hash();
-$rsa->use_no_padding();
+
+# see page 22 of RFC 4880 for why i think this is the right padding
+# choice to use:
+$rsa->use_pkcs1_padding();
 
 if (! $rsa->check_key()) {
   die "key does not check";
@@ -238,11 +249,11 @@ if (! $rsa->check_key()) {
 
 my $version = pack('C', 4);
 # strong assertion of identity:
-my $sigtype = pack('C', 0x13);
+my $sigtype = pack('C', $sig_types->{positive_certification});
 # RSA
-my $pubkey_algo = pack('C', 1);
+my $pubkey_algo = pack('C', $asym_algos->{rsa});
 # SHA1
-my $hash_algo = pack('C', 2);
+my $hash_algo = pack('C', $digests->{sha1});
 
 # FIXME: i'm worried about generating a bazillion new OpenPGP
 # certificates from the same key, which could easily happen if you run
@@ -252,36 +263,51 @@ my $hash_algo = pack('C', 2);
 # could an environment variable (if set) override the current time?
 my $timestamp = time();
 
-my $creation_time_packet = pack('CCN', 5, 2, $timestamp);
+my $creation_time_packet = pack('CCN', 5, $subpacket_types->{sig_creation_time}, $timestamp);
 
 
 # FIXME: HARDCODED: what if someone wants to select a different set of
 # usage flags?  For now, we do only authentication.
-my $flags = $usage_flags->{authenticate};
-my $usage_packet = pack('CCC', 2, 27, $flags);
+my $usage_packet = pack('CCC', 2, $subpacket_types->{usage_flags}, $usage_flags->{authenticate});
 
 
 # FIXME: HARDCODED: how should we determine how far off to set the
 # expiration date?  default is to expire in 2 days, which is insanely
 # short (but good for testing).
 my $expires_in = 86400*2;
-my $expiration_packet = pack('CCN', 5, 9, $expires_in);
+my $expiration_packet = pack('CCN', 5, $subpacket_types->{key_expiration_time}, $expires_in);
 
 
 # prefer AES-256, AES-192, AES-128, CAST5, 3DES:
-my $pref_sym_algos = pack('CCCCCCC', 6, 11, 9, 8, 7, 3, 2);
+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, 21, 2, 8, 3);
+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, 22, 2, 3, 1);
+my $pref_zip_algos = pack('CCCCC', 4, $subpacket_types->{preferred_compression},
+                         $zips->{zlib},
+                         $zips->{bzip2},
+                         $zips->{zip}
+                        );
 
 # we support the MDC feature:
-my $features = pack('CCC', 2, 30, 1);
+my $feature_subpacket = pack('CCC', 2, $subpacket_types->{features},
+                            $features->{mdc});
 
 # keyserver preference: only owner modify (???):
-my $keyserver_pref = pack('CCC', 2, 23, 0x80);
+my $keyserver_pref = pack('CCC', 2, $subpacket_types->{keyserver_prefs},
+                         $keyserver_prefs->{nomodify});
 
 my $subpackets_to_be_hashed =
   $creation_time_packet.
@@ -290,7 +316,7 @@ my $subpackets_to_be_hashed =
   $pref_sym_algos.
   $pref_hash_algos.
   $pref_zip_algos.
-  $features.
+  $feature_subpacket.
   $keyserver_pref;
 
 my $subpacket_octets = pack('n', length($subpackets_to_be_hashed));
@@ -305,8 +331,7 @@ my $sig_data_to_be_hashed =
 
 my $pubkey = make_rsa_pub_key_body($rsa, $timestamp);
 
-#open(KEYFILE, "</home/wt215/gpg-test/key-data");
-my $key_data = make_packet(6, $pubkey);
+my $key_data = make_packet($packet_types->{pubkey}, $pubkey);
 
 # take the last 8 bytes of the fingerprint as the keyid:
 my $keyid = substr(fingerprint($rsa, $timestamp), 20 - 8, 8);
@@ -330,7 +355,7 @@ my $datatosign =
 my $data_hash = Digest::SHA1::sha1_hex($datatosign);
 
 
-my $issuer_packet = pack('CCa8', 9, 16, $keyid);
+my $issuer_packet = pack('CCa8', 9, $subpacket_types->{issuer}, $keyid);
 
 my $sig = Crypt::OpenSSL::Bignum->new_from_bin($rsa->sign($datatosign));
 
@@ -342,8 +367,8 @@ my $sig_body =
   mpi_pack($sig);
 
 print
-  make_packet(6, $pubkey).
-  make_packet(13, $uid).
-  make_packet(2, $sig_body);
+  make_packet($packet_types->{pubkey}, $pubkey).
+  make_packet($packet_types->{uid}, $uid).
+  make_packet($packet_types->{sig}, $sig_body);