mirror of git://git.gnupg.org/gnupg.git
164 lines
5.4 KiB
Plaintext
164 lines
5.4 KiB
Plaintext
|
|
G10 - The GNU Encryption and Signing Tool
|
|
------------------------------------------
|
|
|
|
|
|
THIS IS VERSION IS ONLY A TEST VERSION ! YOU SHOULD NOT
|
|
USE IT FOR OTHER PURPOSES THAN EVALUATING THE CURRENT CODE.
|
|
|
|
* Only some parts work.
|
|
|
|
* The data format may change in the next version!
|
|
|
|
* Some features are not yet implemented
|
|
|
|
|
|
I provide this version as a reality check to start discussion.
|
|
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".
|
|
|
|
|
|
See the file COPYING for copyright and warranty information.
|
|
|
|
|
|
Due to the fact that G10 does not use use any patented algorithm,
|
|
it cannot be compatible to old PGP versions, because those use
|
|
IDEA (which is worldwide patented) and RSA (which is patented in
|
|
the United States until Sep 20, 2000). I'm sorry about this, but
|
|
this is the world we have created (e.g. by using proprietary software).
|
|
|
|
|
|
Because the OpenPGP standard is still a draft, G10 is not yet
|
|
compatible to it (or PGP 5) - but it will. The data structures
|
|
used are compatible with PGP 2.x, so it can parse an list such files
|
|
and PGP should be able to parse data created by G10 and complain
|
|
about unsupported algorithms.
|
|
|
|
The default algorithms used by G10 are ElGamal for public-key
|
|
encryption and signing; Blowfish with a 160 bit key for protecting
|
|
the secret-key components, conventional and session encryption;
|
|
RIPE MD-160 to create message digest. DSA, SHA-1 and CAST are
|
|
also implemented, but not used on default. I decided not
|
|
to use DSA as default signing algorithm, because it allows only for
|
|
1024 bit keys and this may be not enough in a couple of years.
|
|
|
|
|
|
Resources
|
|
---------
|
|
G10 needs a directory "~/.g10" to store the default keyrings
|
|
and other files.
|
|
|
|
|
|
Key Generation
|
|
--------------
|
|
Create a key pair with this command:
|
|
|
|
g10 --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 emit only bytes if the kernel can gather enough entropy.
|
|
If you see no progress, you should start some other activities such
|
|
as a mouse moves or a "find /". Because we have no hardware device
|
|
to generate random we have to use this method.
|
|
|
|
Key generation shows progress by printing different characters to
|
|
stderr:
|
|
"." Miller-Rabin test failed.
|
|
"+" Miller-Rabin test succeeded.
|
|
"!" Reloading the pool with fresh prime numbers
|
|
"^" Checking a new value for the generator
|
|
"~" Issued during generator checks
|
|
"<" Size of one factor decreased
|
|
">" Size of one factor increased
|
|
|
|
The prime number for ElGamal is generated this way:
|
|
|
|
1) Make a prime number q of 160, 200, 240 bits (depending on the keysize).
|
|
2) Select the length of the other prime factors to be at least the size
|
|
of q and calculate the number of prime factors needed
|
|
3) Make a pool of prime number, each of the length determined in step 2
|
|
4) Get a new permutation out of the pool or continue with step 3
|
|
if we have tested all permutations.
|
|
5) Calculate a candidate prime p = 2 * q * p[1] * ... * p[n] + 1
|
|
6) Check that this prime has the correct length (this may change q if
|
|
it seems not to be possible to make a prime of the desired length)
|
|
7) Check whether this is a prime using trial divisions and the
|
|
Miller-Rabin test.
|
|
8) Continue with step 4 if we did not find a prime in step 7.
|
|
9) Find a generator for that prime.
|
|
|
|
|
|
Signatures
|
|
----------
|
|
To create a signature, use this:
|
|
|
|
g10 -s file
|
|
|
|
This creates a file file.g10 which is compressed and has a signature
|
|
attached.
|
|
|
|
g10 -sa file
|
|
|
|
Same as above, but file.g10 is ascii armored.
|
|
|
|
g10 -s -o out file
|
|
|
|
Creates a signature of file, but writes the output to the file "out".
|
|
|
|
Encryption
|
|
----------
|
|
To encrypt data use this:
|
|
|
|
g10 -e -r heine file
|
|
|
|
This encrypts files with the public key of "heine" and writes it
|
|
to "file.g10"
|
|
|
|
echo "hallo" | g10 -ea -r heine | mail heine
|
|
|
|
Ditto, but encrypts "hallo\n" and mails it as ascii armored message.
|
|
|
|
|
|
Debug Flags
|
|
-----------
|
|
Use the option "--debug n" to output debug informations. 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
|
|
|
|
|
|
|
|
Other Notes
|
|
-----------
|
|
This is work in progress, so you may find duplicated code fragments,
|
|
ugly data structures, weird usage of filenames and other thinks.
|
|
I will run "indent" over the source when making a real distribution,
|
|
but for now I stick to my own formatting rules.
|
|
|
|
Compression does not work always; this is the reason that "-z 0"
|
|
is the default.
|
|
|
|
This will be cleaned up of course.
|
|
|
|
The primary FTP site is "ftp://ftp.guug.de/pub/gcrypt/"
|
|
The primary WWW page is "http://www.d.shuttle.de/isil/g10.html"
|
|
|
|
Please direct bug reports to <g10-bugs@isil.d.shuttle.de> or better
|
|
post them to the mailing list <g10@net.lut.ac.uk>.
|
|
|
|
Have fun
|
|
|
|
Werner
|
|
|