each recipient. This form B<must> be used if customised parameters are
required (for example to specify RSA-OAEP).
+Only certificates carrying RSA, Diffie-Hellman or EC keys are supported by this
+option.
+
=item B<-keyid>
Use subject key identifier to identify certificates instead of issuer name and
=head1 HISTORY
The use of multiple B<-signer> options and the B<-resign> command were first
-added in OpenSSL 1.0.0
-
-The B<keyopt> option was first added in OpenSSL 1.1.0
+added in OpenSSL 1.0.0.
-The use of B<-recip> to specify the recipient when encrypting mail was first
-added to OpenSSL 1.1.0
+The B<keyopt> option was first added in OpenSSL 1.0.2.
-Support for RSA-OAEP and RSA-PSS was first added to OpenSSL 1.1.0.
+Support for RSA-OAEP and RSA-PSS was first added to OpenSSL 1.0.2.
The use of non-RSA keys with B<-encrypt> and B<-decrypt> was first added
-to OpenSSL 1.1.0.
+to OpenSSL 1.0.2.
-The -no_alt_chains options was first added to OpenSSL 1.1.0.
+The -no_alt_chains options was first added to OpenSSL 1.0.2b.
=head1 COPYRIGHT
=head1 NOTES
-Only certificates carrying RSA keys are supported so the recipient certificates
-supplied to this function must all contain RSA public keys, though they do not
-have to be signed using the RSA algorithm.
+Only certificates carrying RSA, Diffie-Hellman or EC keys are supported by this
+function.
EVP_des_ede3_cbc() (triple DES) is the algorithm of choice for S/MIME use
because most clients will support it.