mirror of git://git.gnupg.org/gnupg.git
233 lines
7.1 KiB
Plaintext
233 lines
7.1 KiB
Plaintext
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G10 - The GNU Encryption and Signing Tool
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------------------------------------------
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THIS IS VERSION IS ONLY A TEST VERSION ! YOU SHOULD NOT
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USE IT FOR OTHER PURPOSES THAN EVALUATING THE CURRENT CODE.
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* The data format may change in the next version!
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* Some features are not yet implemented
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I provide this version as a reality check to start discussion.
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Please subscribe to g10@net.lut.ac.uk by sending a mail with
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the word "subscribe" in the body to "g10-request@net.lut.ac.uk".
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See the file COPYING for copyright and warranty information.
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Due to the fact that G10 does not use use any patented algorithm,
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it cannot be compatible to old PGP versions, because those use
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IDEA (which is worldwide patented) and RSA (which is patented in
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the United States until Sep 20, 2000). I'm sorry about this, but
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this is the world we have created (e.g. by using proprietary software).
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Because the OpenPGP standard is still a draft, G10 is not yet
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compatible to it (or PGP 5) - but it will. The data structures
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used are compatible with PGP 2.x, so it can parse an list such files
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and PGP should be able to parse data created by G10 and complain
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about unsupported algorithms.
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The default algorithms used by G10 are ElGamal for public-key
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encryption and signing; Blowfish with a 160 bit key for protecting
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the secret-key components, conventional and session encryption;
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RIPE MD-160 to create message digest. DSA, SHA-1 and CAST are
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also implemented, but not used on default. I decided not
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to use DSA as default signing algorithm, because it allows only for
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1024 bit keys and this may be not enough in a couple of years.
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Installation
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------------
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1) "./configure"
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to enable the integrated malloc debugging stuff, use:
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"./configure --enable-m-debug"
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2) "make"
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3) "make install"
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4) You end up with a binary "g10" in /usr/local/bin
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Resources
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---------
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G10 needs a directory "~/.g10" to store the default keyrings
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and other files.
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Key Generation
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--------------
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g10 --gen-key
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This asks some questions and then starts key generation. To create
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good random numbers for prime number generation, it uses a /dev/random
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which will emit only bytes if the kernel can gather enough entropy.
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If you see no progress, you should start some other activities such
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as mouse moves or a "find /". Because we have no hardware device
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to generate random we have to use this method.
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Key generation shows progress by printing different characters to
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stderr:
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"." Miller-Rabin test failed.
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"+" Miller-Rabin test succeeded.
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"!" Reloading the pool with fresh prime numbers
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"^" Checking a new value for the generator
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"~" Issued during generator checks
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"<" Size of one factor decreased
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">" Size of one factor increased
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The prime number for ElGamal is generated this way:
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1) Make a prime number q of 160, 200, 240 bits (depending on the keysize).
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2) Select the length of the other prime factors to be at least the size
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of q and calculate the number of prime factors needed
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3) Make a pool of prime number, each of the length determined in step 2
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4) Get a new permutation out of the pool or continue with step 3
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if we have tested all permutations.
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5) Calculate a candidate prime p = 2 * q * p[1] * ... * p[n] + 1
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6) Check that this prime has the correct length (this may change q if
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it seems not to be possible to make a prime of the desired length)
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7) Check whether this is a prime using trial divisions and the
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Miller-Rabin test.
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8) Continue with step 4 if we did not find a prime in step 7.
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9) Find a generator for that prime.
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You can sign a key with this command:
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g10 --sign-key Donald
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To sign the key of of "Donald" with your default userid
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g10 --sign-key -u Karl -u Joe Donald
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To sign the key of of "Donald" with the userids of "Karl" and "Joe".
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All existing signatures are checked, if some are invalid, a menu is
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offered to delete some of them, and the you are asked for every user
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wether you want to sign this key.
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You may remove a signature at any time by usiing the option "--edit-sig",
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which also asks for the sigs to remove.
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Sign
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----
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g10 -s file
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This creates a file file.g10 which is compressed and has a signature
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attached.
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g10 -sa file
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Same as above, but file.g10 is ascii armored.
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g10 -s -o out file
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Creates a signature of file, but writes the output to the file "out".
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Encrypt
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-------
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g10 -e -r heine file
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This encrypts files with the public key of "heine" and writes it
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to "file.g10"
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echo "hallo" | g10 -ea -r heine | mail heine
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Ditto, but encrypts "hallo\n" and mails it as ascii armored message.
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Sign and Encrypt
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----------------
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g10 -se -r heine file
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This encrypts files with the public key of "heine" and writes it
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to "file.g10" after signing it with the default user id.
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g10 -se -r heine -u Suttner file
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Ditto, but sign the file with the user id "Suttner"
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Examine a data or key file
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--------------------------
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g10 --list-packets datafile
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Use this to list the contents of a data file. If the file is encrypted
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you are asked for the passphrase, so that G10 is able to look at the
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inner structure of a encrypted packet.
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Batch mode
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----------
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If you use the option "--batch", G10 runs in non-interactive mode and
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never prompts for input data. This even does not allow to enter
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passphrase; until we have a better solution (something like ssh-agent),
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you can use the option "--passhrase-fd n", which works like PGPs
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PGPPASSFD.
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Batch mode also causes PGP to terminate as soon as a BAD signature is
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detected.
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Exit status
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-----------
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G10 returns with an exit status of 1 if in batch mode and a bad signature
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has been detected or 2 or higher for all other errors. You should parse
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stderr to get detailed informations about the errors.
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Debug Flags
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-----------
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Use the option "--debug n" to output debug informations. This option
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can be used multiple times, all values are ORed; n maybe prefixed with
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0x to use hex-values.
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value used for
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----- ----------------------------------------------
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1 packet reading/writing
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2 MPI details
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4 ciphers and primes (may reveal sensitive data)
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8 iobuf filter functions
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16 iobuf stuff
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32 memory allocation stuff
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64 caching
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128 show memory statistics at exit
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Other Notes
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-----------
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This is work in progress, so you may find duplicated code fragments,
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ugly data structures, weird usage of filenames and other thinks.
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I will run "indent" over the source when making a real distribution,
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but for now I stick to my own formatting rules.
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The primary FTP site is "ftp://ftp.guug.de/pub/gcrypt/"
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The primary WWW page is "http://www.d.shuttle.de/isil/g10.html"
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Please direct bug reports to <g10-bugs@isil.d.shuttle.de> or better
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post them to the mailing list <g10@net.lut.ac.uk>.
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