Podepisovani a kontrola RPM baliku pomoci GPG

[Milan Kerslager]

V soucasne dobe je jednoznacne nejlepsi pouzivat GPG (balicky
gnupg-1.0.1-3.i386.rpm, gnupg-modules-1.1-3.i386.rpm). Pomoci dodatecnych
modulu je mozno s GPG zprovoznit i algoritmy, ktere nejsou z licencnich
duvodu v zakladni sade (IDEA, RSA). GPG je pomoci techto externich modulu
zpetne kompatibilni jak s PGPv2, tak s PGPv5 (oboje non-free).

Zakladem podepisovani je asimetricka sifra, coz znamena, ze existuje vzdy
dvojice klicu (verejny a soukromy), pomoci kterych se koduje. Soukromy
klic se chrani jeste frazi (ovykle delsi heslo), ktera jej chrani pred
zneuzitim (i pres to by jste o nej meli dobre pecovat).

Novou dvojici klicu vytvorime pomoci parametru --gen-key

[huzva na monkey huzva]$ gpg --gen-key
gpg (GnuPG) 1.0.1; Copyright (C) 1999 Free Software Foundation, Inc.
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions. See the file COPYING for details.

gpg: /home/huzva/.gnupg/secring.gpg: keyring created
gpg: /home/huzva/.gnupg/pubring.gpg: keyring created
Please select what kind of key you want:
   (1) DSA and ElGamal (default)
   (2) DSA (sign only)
   (4) ElGamal (sign and encrypt)
Your selection? 1
DSA keypair will have 1024 bits.
About to generate a new ELG-E keypair.
              minimum keysize is  768 bits
              default keysize is 1024 bits
    highest suggested keysize is 2048 bits
What keysize do you want? (1024)
Requested keysize is 1024 bits
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0)
Key does not expire at all
Is this correct (y/n)? y

You need a User-ID to identify your key; the software constructs the user
id
from Real Name, Comment and Email Address in this form:
    "Heinrich Heine (Der Dichter) <heinrichh na duesseldorf.de>"

Real name: Rene Huzva
Email address: rene.huzva na spsselib.hiedu.cz
Comment:
You selected this USER-ID:
    "Rene Huzva <rene.huzva na spsselib.hiedu.cz>"

Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o
You need a Passphrase to protect your secret key.

We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
.+++++.++++++++++.++++++++++++++++++++++++++++++++++++++++..++++++++++.+++++.+++++++++++++++.++++++++++.+++++.++++++++++.++++++++++++++++++++>++++++++++................>+++++.+++++
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
+++++++++++++++.++++++++++.++++++++++.++++++++++++++++++++.+++++++++++++++.+++++++++++++++...++++++++++.++++++++++.+++++++++++++++.++++++++++>+++++...............>.+++++.................<+++++.......>+++++.......<+++++.>+++++.................................................................................<+++++.>.+++++...............<.+++++...>+++++..<+++++.......+++++^^^^
public and secret key created and signed.
[huzva na monkey huzva]$

Pak vytvorime konfiguracni soubor pro RPM, ktery muze vypadat treba
takhle:

[root na monkey /root]# cat .rpmmacros
%_signature gpg
%_gpg_path /root/.gnupg
%_gpg_name Rena Huzva <rene.huzva na spsselib.hiedu.cz>
[root na monkey /root]# 

Balicek muzeme podepsat pri generovani nebo dodatecne. Pri dodatecnem
podepisovani je rozdil mezi pridanim sveho klice (--addsign) a nahrazenim
vsech soucasnych klicu svym (--resign).

Pr: rpm --resig balik*.rpm
    rpm --addsign jiny-balik.rpm
    rpm -ba --sign SPEC/balik.spec

Pokud chcete zverejnit svuj verejny klic, musite jej exportovat do ASCII
podoby:

    gpg -a --export

Importovat cizi verejne klice, abyste mohli kontrolovat baliky:

    gpg --import soubor_s_klicem

A pak kontrolovat pomoci RPM:

    rpm -K balik.rpm

--
                        Milan Kerslager
                        E-mail: milan.kerslager na spsselib.hiedu.cz
                        WWW:    http://www.spsselib.hiedu.cz/~kerslage/