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Update docs with algorithm options.

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Dr. Stephen Henson 2006-07-08 10:01:33 +00:00
parent 383b8b8ca9
commit 8d970ca70b
1 changed files with 66 additions and 1 deletions
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67
doc/apps/pkeyutl.pod
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@ -70,6 +70,11 @@ the input file is a public key.
the input is a certificate containing a public key.
=item B<-rev>
reverse the order of the input buffer. This is useful for some libraries
(such as CryptoAPI) which represent the buffer in little endian format.
=item B<-sign>
sign the input data and output the signed result. This requires
@ -112,14 +117,66 @@ B<-verifyrecover> option when an ASN1 structure is signed.
The operations and options supported vary according to the key algorithm
and its implementation. The OpenSSL operations and options are indicated below.
Unless otherwise mentioned all algorithms support the B<digest:alg> option
which specifies the digest in use for sign, verify and verifyrecover operations.
The value B<alg> should represent a digest name as used in the
EVP_get_digestbyname() function for example B<sha1>.
=head1 RSA ALGORITHM
The RSA algorithm supports encrypt, decrypt, sign, verify and verifyrecover
operations in general. Some padding modes only support some of these
operations however.
[NB: more to be added later]
=over 4
=item -B<rsa_padding_mode:mode>
This sets the RSA padding mode. Acceptable values for B<mode> are B<pkcs1> for
PKCS#1 padding, B<sslv23> for SSLv23 padding, B<none> for no padding, B<oaep>
for B<OAEP> mode, B<x931> for X9.31 mode and B<pss> for PSS.
In PKCS#1 padding if the message digest is not set then the supplied data is
signed or verified directly instead of using a B<DigestInfo> structure. If a
digest is set then the a B<DigestInfo> structure is used and its the length
must correspond to the digest type.
For B<oeap> mode only encryption and decryption is supported.
For B<x931> if the digest type is set it is used to format the block data
otherwise the first byte is used to specify the X9.31 digest ID. Sign,
verify and verifyrecover are can be performed in this mode.
For B<pss> mode only sign and verify are supported and the digest type must be
specified.
=item B<rsa_pss_saltlen:len>
For B<pss> mode only this option specifies the salt length. Two special
values are supported: -1 sets the salt length to the digest length. When
signing -2 sets the salt length to the maximum permissible value. When
verifying -2 causes the salt length to be automatically determined based
on the B<PSS> block structure.
=back
=head1 DSA ALGORITHM
The DSA algorithm supports signing and verification operations only. Currently
there are no additional options other than B<digest>. Only the SHA1
digest can be used and this digest is assumed by default.
=head1 DH ALGORITHM
The DH algorithm only supports the derivation operation and no additional
options.
=head1 EC ALGORITHM
The EC algorithm supports sign, verify and derive operations. The sign and
verify operations use ECDSA and derive uses ECDH. Currently there are no
additional options other than B<digest>. Only the SHA1 digest can be used and
this digest is assumed by default.
=head1 EXAMPLES
@ -135,6 +192,14 @@ Verify the signature (e.g. a DSA key):
openssl pkeyutl -verify -in file -sigfile sig -inkey key.pem
Sign data using a message digest value (this is currently only valid for RSA):
openssl pkeyutl -sign -in file -inkey key.pem -out sig -pkeyopt digest:sha256
Derive a shared secret value:
openssl pkeyutl -derive -inkey key.pem -peerkey pubkey.pem -out secret
=head1 SEE ALSO
L<genpkey(1)|genpkey(1)>, L<pkey(1)|pkey(1)>, L<rsautl(1)|rsautl(1)>