certpatch(8) add subjectAltName identities to X.509 certificates


certpatch [-t identity-type ] -i identity -k signing-key input-certificate output-certificate


certpatch alters PEM-encoded X.509 certificates by adding a subjectAltName extension containing an identity used by the signature-based authentication schemes of the ISAKMP protocol. After the addition the certificate will be signed once again with the supplied CA signing key.

The options are as follows:

-t identity-type
If given, the -t option specifies the type of the given identity. Currently ip fqdn and ufqdn are recognized. The default is ip
-i identity
The -i option takes an argument which is the identity to put into the subjectAltName field of the certificate. If the identity-type is ip this argument should be an IPv4 address in dotted decimal notation.
-k signing-key
The -k option specifies the key used for signing the certificate once the subjectAltName extension has been added. The key is specified by the filename where it is stored in PEM format.