time_t was used in the signature and key packet headers,
which is typedef of long and is different on 32 and 64 bit architectures.
Signature and key format should be independent of architecture.
Similar to GPG, I have changed the type to uint32_t.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: James Morris <jmorris@namei.org>

It was reported that DIGSIG is confusing name for digital signature
module. It was suggested to rename DIGSIG to SIGNATURE.

Requested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: James Morris <jmorris@namei.org>

This patch implements RSA digital signature verification using GnuPG library.

The format of the signature and the public key is defined by their respective
headers. The signature header contains version information, algorithm,
and keyid, which was used to generate the signature.
The key header contains version and algorythim type.
The payload of the signature and the key are multi-precision integers.

The signing and key management utilities evm-utils provide functionality
to generate signatures and load keys into the kernel keyring.
When the key is added to the kernel keyring, the keyid defines the name
of the key.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>