If you wish to verify that a package has not been corrupted or tampered
with, examine only the md5sum by typing the following command at a shell
prompt (<rpm-file> with file name of
the RPM package):
rpm -K --nosignature <rpm-file> |
The message <rpm-file>:
md5 OK is displayed. This brief message means that
the file was not corrupted by the download. To see a more verbose
message, replace -K with -Kvv in the
command.
On the other hand, how trustworthy is the developer who created the
package? If the package is signed with the
developer's GnuPG key, you know that the
developer really is who they say they are.
An RPM package can be signed using Gnu Privacy
Guard (or GnuPG), to help you make certain your downloaded
package is trustworthy.
GnuPG is a tool for secure communication; it is a complete and free
replacement for the encryption technology of PGP, an electronic privacy
program. With GnuPG, you can authenticate the validity of documents and
encrypt/decrypt data to and from other recipients. GnuPG is capable of
decrypting and verifying PGP 5.x files as
well.
During installation, GnuPG is installed by default. That way you can
immediately start using GnuPG to verify any packages that you receive
from Red Hat. First, you must import Red Hat's public key.
To verify Red Hat packages, you must import the Red Hat GPG key. To
do so, execute the following command at a shell prompt:
rpm --import /usr/share/rhn/RPM-GPG-KEY |
To display a list of all keys installed for RPM verification, execute
the command:
For the Red Hat key, the output includes:
gpg-pubkey-db42a60e-37ea5438 |
To display details about a specific key, use rpm
-qi followed by the output from the previous command:
rpm -qi gpg-pubkey-db42a60e-37ea5438 |
To check the GnuPG signature of an RPM file after importing the
builder's GnuPG key, use the following command (replace
<rpm-file> with filename of the RPM
package):
If all goes well, the following message is displayed:
md5 gpg OK. That means that the
signature of the package has been verified and that it is not
corrupt.
