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@@ -1,17 +1,17 @@ ------BEGIN PGP SIGNED MESSAGE----- - - GnuPG - The GNU Privacy Guard - ------------------------------- - Version 0.4 - - As you can see from the version number, the program may have some - bugs and some features may not work at all - please report this to - the mailing list. - - On a Linux box (version 2.x.x, alpha or x86 CPU) it should - work reliably. You may create your key on such a machine and - use it. Please verify the tar file; there is a PGP and a GnuPG - signature available. My PGP 2 key is well known and published in + GnuPG - The GNU Privacy Guard + ------------------------------- + Version 0.9 + + GnuPG is now in Beta test and you should report all bugs to the + mailing list (see below). The 0.9.x versions are mainly released + to fix all remaining serious bugs. As soon as version 1.0 is out, + development will continue with a 1.1 series and bug fixes for the + 1.0 version are released as needed. + + GnuPG works best on GNU/Linux or *BSD. Other Unices are + also supported but not as good tested as those Freenix ones. + Please verify the tar file; there is a PGP2 and a GnuPG/PGP5 + signature available. My PGP2 key is well known and published in the "Global Trust Register for 1998", ISBN 0-9532397-0-5. I have included my pubring as "g10/pubring.asc", which contains @@ -19,39 +19,37 @@ "pub 1024D/57548DCD 1998-07-07 Werner Koch (gnupg sig) <dd9jn@gnu.org>" "Key fingerprint = 6BD9 050F D8FC 941B 4341 2DCC 68B7 AB89 5754 8DCD" - Old version of gnupg are signed with this key: - "pub 1312G/FF3EAA0B 1998-02-09 Werner Koch <wk@isil.d.shuttle.de>" - "Key fingerprint = 8489 6CD0 1851 0E33 45DA CD67 036F 11B8 FF3E AA0B" - - My usual key is now: + My new DSA key is: "pub 1024D/621CC013 1998-07-07 Werner Koch <werner.koch@guug.de>" "Key fingerprint = ECAF 7590 EB34 43B5 C7CF 3ACB 6C7E E1B8 621C C013" - You may add it to your GnuPG pubring and use it in the future to + You may want add it to your GnuPG pubring and use it in the future to verify new releases. Because you verified this README file and _checked_that_it_is_really_my PGP2 key 0C9857A5, you can be sure that the above fingerprints are correct. Please subscribe to g10@net.lut.ac.uk by sending a mail with the word "subscribe" in the body to "g10-request@net.lut.ac.uk". - This mailing is closed (only subscribers can post) to avoid spam. + This mailing list is a closed one (only subscribers are allowed + to post) to avoid misuse by folks who don't know the Netiquette + and trash you mailspool with commercial junk. See the file COPYING for copyright and warranty information. + GnuPG is in compliance with RFC2440 (OpenPGP), see doc/OpenPGP for + details. + Due to the fact that GnuPG does not use use any patented algorithm, - it cannot be compatible with old PGP versions, because those use + it cannot be compatible with PGP2 versions; PGP 2.x does only use IDEA (which is patented worldwide) and RSA (which is patented in the United States until Sep 20, 2000). - GnuPG is in compliance with RFC2440 (OpenPGP), see doc/OpenPGP for - deatils. - - The default algorithms are now DSA and ELGamal. ELGamal for signing + The default algorithms are now DSA and ElGamal. ElGamal for signing is still available, but due to the larger size of such signatures it is depreciated (Please note that the GnuPG implementation of ElGamal - signatures is *not* insecure). Symmetric algorithms are: 3DES, Blowfish - and CAST5, Digest algorithms are MD5, RIPEMD160, SHA1 and TIGER/192. - + signatures is *not* insecure). Symmetric algorithms are: 3DES, + Blowfish and CAST5 (Twofish will come soon), available digest + algorithms are MD5, RIPEMD160, SHA1 and TIGER/192. Installation @@ -67,27 +65,51 @@ 3) "make install" - 4) You end up with a binary "gpg" in /usr/local/bin + 4) You end up with the binaries "gpg" and "gpgm" in /usr/local/bin. + + 5) Optional, but suggested: install the binary "gpg" as suid root. + - 5) Optional, but suggested: install the program "gpg" as suid root. + Intro + ----- + This is a brief overview how to use GnuPG - it is highly suggested + that you read the manual^H^H^H more information about the use + of cryptography. GnuPG is only the technical tool to do it and + the security highly depends on that YOU KNOW WHAT YOU ARE DOING. + If you already have a DSA key from PGP 5 (they call them DH/ElGamal) + you can simply copy the pgp keyrings over the GnuPG keyrings after + running gpg once, so that it can create the correct directory. - Key Generation - -------------- + The normal way to create a key is: gpg --gen-key This asks some questions and then starts key generation. To create - good random numbers for prime number generation, it uses a /dev/random - which will only emit bytes if the kernel can gather enough entropy. - If you see no progress, you should start some other activities such - as mouse moves, "find /" or using the keyboard (in another window). - Because we have no hardware device to generate randomness we have to - use this method. - - You should make a revocation certificate in case someone gets - knowledge of your secret key or you forgot your passphrase: + good random numbers for the key parameters, GnuPG needs to gather + enough noise (entropy) from your system. If you see no progress + during key generation you should start some other activities such + as mouse moves or hitting on the CTRL and SHIFT keys. + + Generate a key ONLY on a machine where you have direct physical + access - don't do it over the network or on a machine used also + by others - especially if you have no access to the root account. + + When you are asked for a passphrase; use a good one which you can easy + remember. Don't make the passphrase too long because you have to + type it for every decryption or signing; but - AND THIS IS VERY + IMPORTANT - use a good one which is not easily guessable as the + security of the whole system relies on your secret key and the + passphrase is used to protect this secret key in case someone was + able to get access to your secret keyring. A good way to select + a passphrase is to figure out a short nonsense sentence which makes + some sense for you and modify it by inserting extra spaces, non-letters + and changing the case of some characters - this is really easy to + remember especially if you associate some pictures with it. + + Then you should create a revocation certificate in case someone + gets knowledge of your secret key or you forgot your passphrase: gpg --gen-revoke your_user_id @@ -95,36 +117,7 @@ so that you can print it and (hopefully never) re-create it if your electronic media fails. - If you decided to create a DSA key, you should add an ElGamal - for encryption: - - gpg --add-key user_id_of_your_key - - and follow the displayed instructions (select "ElGamal using v4 packets"). - - - You can sign a key with this command: - - gpg --sign-key Donald - - This let you sign the key of "Donald" with your default userid. - - gpg --sign-key -u Karl -u Joe Donald - - This let you sign the key of of "Donald" with the userids of "Karl" - and "Joe". - All existing signatures are checked; if some are invalid, a menu is - offered to delete some of them, and then you are asked for every user - whether you want to sign this key. - - You may remove a signature at any time using the option "--edit-sig", - which asks for the sigs to remove. Self-signatures are not removable. - - - - - Sign - ---- + Now you can use your key to create digital signatures: gpg -s file @@ -133,66 +126,191 @@ gpg -sa file - Same as above, but file.gpg is ascii armored. + Same as above, but creates the file.asc which is ascii armored and + and ready for sending by mail. Note: It is better to use your + mailers features to create signatures (The mailer uses GnuPG to do + this) because the mailer has the ability to MIME encode such + signatures - but this is not a security issue. gpg -s -o out file Creates a signature of file, but writes the output to the file "out". - If you use the option "--rfc1991", gnupg tries to me more compatible - to RFC1991 (pgp 2.x). + Everyone who knows your public key (you can and should publish + your key by putting it on a key server, a web page or in your .plan + file) is now able to check whether you really signed this text; + gpg --verify file - Encrypt - ------- + GnuPG now checks whether the signature is valid and prints an + appropriate message. If the signature is good, you know at least + that the person (or machine) has access to the secret key which + corresponds to the published public key. + If you run gpg without an option it will verify the signature and + create a new file which is identical to the original file. gpg + can also run as a filter, so that you can pipe data to verify + trough it: - gpg -e -r heine file + cat signed-file | gpg | wc -l - This encrypts files with the public key of "heine" and writes it - to "file.gpg" + will check the signature of signed-file and then display the + number of lines in the original file. - echo "hallo" | gpg -ea -r heine | mail heine + To send a message encrypted to someone you can use this: - Ditto, but encrypts "hallo\n" and mails it as ascii armored message. + gpg -e -r heine file + This encrypts file with the public key of the user "heine" and + writes it to "file.gpg" - Sign and Encrypt - ---------------- + echo "hallo" | gpg -ea -r heine | mail heine - gpg -se -r heine file + Ditto, but encrypts "hallo\n" and mails it as ascii armored message + to the user with the mail address heine. - This encrypts files with the public key of "heine" and writes it - to "file.gpg" after signing it with the default user id. + gpg -se -r heine file + This encrypts file with the public key of "heine" and writes it + to "file.gpg" after signing it with your user id. gpg -se -r heine -u Suttner file - Ditto, but sign the file with the user id "Suttner" + Ditto, but sign the file with your alternative user id "Suttner" - Keyring Management - ------------------ - To export your complete keyring(s) do this: + GnuPG has some options to help you publish public keys; this is + called "exporting" a key: - gpg --export + gpg --export >all-my-keys - To export only some user ids do this: + exports all the keys in the keyring and writes them (in a binary format) + to all-my-keys. You may then mail "all-my-keys" as an MIME attachment + to someone else or put it on an FTP server. To export only some + user IDs, you give them as arguments on the command line. - gpg --export userids + To mail a public key or put it on a web page you have to create + the key in ASCII armored format: - Use "-a" or "--armor" to create ASCII armored output. + gpg --export --armor | mail panther@tiger.int - Importing keys is done with the option, you guessed it, "--import": - - gpg --import [filenames] + This will send all your public keys to your friend panther. - New keys are appended to the default keyring and already existing - keys are merged. Keys without a self-signature are ignored. + If you have received a key from someone else you can put it + into your public keyring; is called "importing": + gpg --import [filenames] - How to Specify a UserID - ----------------------- - There are several ways to specify a userID, here are some examples: + New keys are appended to your keyring and already existing + keys are updated. Note that GnuPG does not allow keys which + are not self-signed by the user. + + Because anyone can claim that the public key belongs to her + we must have some way to check that the public key really belongs + to the owner. This can be achieved by comparing the key during + a phone call. Sure, it is not very easy to compare a binary file + by reading the complete hex dump of the file - GnuPG (and nearly + every other program used for management of cryptographic keys) + provides other solutions: + + gpg --fingerprint <username> + + prints the so called "fingerprint" of the given username; this + is a sequence of hex bytes (which you may have noticed in mail + sigs or on business cards) which uniquely identify the public + key - two different keys will always have different fingerprints. + It is easy to compare this fingerprint by phone and I suggest + that you print your fingerprint on the back of your business + card. + + If you don't know the owner of the public key you are in trouble; + but wait: A friend of you knows someone who knows someone who + has met the owner of the public key at some computer conference. + So all the persons between you and the public key holder may now + act as introducer to you; this is done by signing the keys and + thereby certifying the other keys. If you then trust all the + introducers to correctly sign other keys, you can be be sure that + the other key really belongs to the one who claims so. + + There are 2 steps to validate a target key: + 1. First check that there is a complete chain + of signed keys from the public key you want to use + and your key and verify each signature. + 2. Make sure that you have full trust in the certificates + of all the introduces between the public key holder and + you. + Step 2 is the more complicated part because there is no easy way + for a computer to decide who is trustworthy and who is not. GnuPG + leaves this decision to you and will ask you for a trust value + (here also referenced as the owner-trust of a key) for every key + needed to check the chain of certificates. You may choose from: + a) "I don't know" - then it is not possible to use any + of the chains of certificates, in which this key is used + as an introducer, to validate the target key. Use this if + you don't know the introducer. + b) "I do not trust" - Use this if you know that the introducer + does not do a good job in certifying other keys. The effect + is the same as with a) but for a) you may later want to + change the value because you got new information about this + introducer. + c) "I trust marginally" - Use this if you assume that the + introducer knows what he is doing. Together with some + other marginally trusted keys, GnuPG validates the target + key then as good. + d) "I fully trust" - Use this if you really know that this + introducer does a good job when certifying other keys. + If all the introducer are of this trust value, GnuPG + normally needs only one chain of signatures to validate + a target key okay. (But this may be adjusted with the help + of some options). + These information are confidential because they give your + personal opinion on the trustworthy of someone else. Therefore + this data is not stored in the keyring but in the "trustdb" + (~/.gnupg/trustdb.gpg). Do not assign a high trust value just + because the introducer is a friend of you - decide how far she + understands all the implications of key signatures and you may + want to tell him more about public key cryptography so you + can later change the trust value you assigned. + + Okay, here is how GnuPG helps you in key management: Most stuff is + done with the --edit-key command: + + gpg --edit-key <keyid or username> + + GnuPG displays some information about the key and then prompts + for a command (enter "help" to see a list of commands and see + the man page for a more detailed explanation). To sign a key + you select the user ID you want to sign by entering the number + which is displayed in the leftmost column (or do nothing if the + key has only one user ID) and then enter the command "sign" and + follow all the prompts. When you are ready, give the command + "save" (or use "quit" to cancel your actions). + + If you want to sign the key with another user ID of yours, you + must give an "-u" option on the command line together with the + "--edit-key". + + Normally you want to sign only one user ID because GnuPG + does only use one and this keeps the public key certificate + small. Because such key signatures are very important you + should make sure that the signators of your key sign a user ID + which is very likely to stay for a long time - choose one with an + email address you have full control of or do not enter an email + address at all. In future GnuPG will have a way to tell which + user ID is the one with an email address you prefer - because + you have no signatures on this email address it is easy to change + this address. Remember: Your signators sign your public key (the + primary one) together with one od your user IDs - so it is not possible + to change the user ID later without voiding all the signatures. + + Tip: If you hear about a key signing party on a computer conference + join it because this is a very convenient way to get your key + certified (But remember that signatures have nothing to to with the + trust you assign to a key). + + + 7 Ways to Specify a User ID + -------------------------- + There are several ways to specify a user ID, here are some examples: * Only by the short keyid (prepend a zero if it begins with A..F): @@ -216,7 +334,7 @@ The first one is MD5 the others are ripemd160 or sha1. - * By an exact string (not yet implemented): + * By an exact string: "=Heinrich Heine <heinrichh@uni-duesseldorf.de>" @@ -224,17 +342,13 @@ "<heinrichh@uni-duesseldorf.de>" - This can be used by a keyserver instead of a substring to - find this key faster. - - * By the Local ID (from the trustdb): + * By the Local ID (from the trust DB): "#34" - This can be used by a MUA to specify an exact key after selecting + This may be used by a MUA to specify an exact key after selecting a key from GnuPG (by the use of a special option or an extra utility) - * Or by the usual substring: "Heine" @@ -243,14 +357,12 @@ The '*' indicates substring search explicitly. - - Batch mode ---------- If you use the option "--batch", GnuPG runs in non-interactive mode and never prompts for input data. This does not even allow entering the passphrase; until we have a better solution (something like ssh-agent), - you can use the option "--passhrase-fd n", which works like PGPs + you can use the option "--passphrase-fd n", which works like PGPs PGPPASSFD. Batch mode also causes GnuPG to terminate as soon as a BAD signature is @@ -261,8 +373,8 @@ ----------- GnuPG returns with an exit status of 1 if in batch mode and a bad signature has been detected or 2 or higher for all other errors. You should parse - stderr or the output of the fd specified with --status-fd to get detailed - information about the errors. + stderr or better the output of the fd specified with --status-fd to get + detailed information about the errors. Esoteric commands @@ -272,73 +384,41 @@ Use this to list the contents of a data file. If the file is encrypted you are asked for the passphrase, so that GnuPG is able to look at the - inner structure of a encrypted packet. + inner structure of a encrypted packet. This command should be able + to list all kinds of rfc2440 messages. gpgm --list-trustdb - List the contents of the trustdb in a human readable format + List the contents of the trust DB in a human readable format gpgm --list-trustdb <usernames> List the tree of certificates for the given usernames - gpgm --list-trust-path depth username - - List the possible trust paths for the given username, up to the specified - depth. If depth is negative, duplicate introducers are not listed, - because those would increase the trust probability only minimally. - (you must use the special option "--" to stop option parsing when - using a negative number). This option may create new entries in the - trustdb. + gpgm --list-trust-path username - gpgm --print-mds filenames + List the possible trust paths for the given username. The length + of such a trust path is limited by the option --max-cert-depth + which defaults to 5. - List all available message digest values for the fiven filenames - - For more options/commands see the file g10/OPTIONS, or use "gpg --help" - - - Debug Flags - ----------- - Use the option "--debug n" to output debug information. This option - can be used multiple times, all values are ORed; n maybe prefixed with - 0x to use hex-values. - - value used for - ----- ---------------------------------------------- - 1 packet reading/writing - 2 MPI details - 4 ciphers and primes (may reveal sensitive data) - 8 iobuf filter functions - 16 iobuf stuff - 32 memory allocation stuff - 64 caching - 128 show memory statistics at exit - 256 trust verification stuff + For more options/commands see the man page or use "gpg --help". Other Notes ----------- - This is work in progress, so you may find duplicated code fragments, - ugly data structures, weird usage of filenames and other things. The primary FTP site is "ftp://ftp.gnupg.org/pub/gcrypt/" The primary WWW page is "http://www.gnupg.org" - If you like, send your keys to <gnupg-keys@isil.d.shuttle.de>; use - "gpg --export --armor | mail gnupg-keys@isil.d.shuttle.de" to do this. + See http://www.gnugp.org/mirrors.html for a list of FTP mirrors + and use them if possible. Please direct bug reports to <gnupg-bugs@gnu.org> or better - post them to the mailing list <g10@net.lut.ac.uk> (this is a closed list, - please subscribe before posting, see above (~line 33)). - + post them to the mailing list <g10@net.lut.ac.uk> (this is a + closed list - subscribe before posting, see above (~line 33)). + Please direct questions about GnuPG to the mailing list or + one of the pgp newsgroups; this gives me more time to improve + GnuPG. Commercial support for GnuPG will be availabe soon. ------BEGIN PGP SIGNATURE----- -Version: GnuPG v0.4.4 (GNU/Linux) -Comment: For info finger gcrypt@ftp.guug.de + Have fun and remember: Echelon is looking at you kid. -iQB1AwUBNlXAUh0Z9MEMmFelAQFmhwL/RfW9WxAMTh/edDy0yGTJjDgo7d/Kfmtq -8C0LJ4b2M0py1ctW6jZyiQsYtvkrttKiTYXGtRoIzVFWX2hqABKPCTHzOeXQEOSu -ro5fnRwsuj9cRxhH8lpN+diY+m1E5Fu3 -=sciv ------END PGP SIGNATURE----- |