=head1 MODES OF OPERATION The modes of operation described in this section are mutually exclusive. In other words, only one mode may be specified per invocation. =over 5 =item B<{-s|--sign-payload}> B<{-k|--key-file}> B B B<[payload ...]> Use B to digitally sign the specified B. The B, as specified by the B<--key-file> argument, must be a PEM-encoded DSA or RSA key. For each B signed, a corresponding signature file will be created. Signature files have the same basename as the original B, and they end with a '.sig' suffix. The format of a signature file is a single line of base64-encoded data. To allow for automated or batch signing, B will honor the DSV_PASSPHRASE environment variable so long as it's less than DSV_MAX_PASSPHRASE_LENGTH bytes long -- this length is defined in dsv.h. While this mechanism is supported, its use in production environments is not recommended because it increases the risk of passphrase exposure. =item B<{-V|--verify-signature}> B<{-f|--cert-file}> B B B Use the specified B and B to verify the integrity of B. The B, as specified by the B<--cert-file> argument, must be a PEM-encoded certificate. =item B<{-V|--verify-signature}> B<{-t|--cert-tree}> B B B Use the specified B and all certificates stored in the certificate B to verify the integrity of B. The files stored in the certificate B must be PEM-encoded certificates -- invalid and non-PEM-encoded files are silently ignored. Each certificate in the certificate B is used, in turn, to verify the B integrity. The verification process does not stop until a match is found or all certificates have been tried. Note that B will not search for certificates in sub-directories of the specified B. =item B<{-v|--version}> Display version information and exit. =back