do not verify the signers certificate of a signed message.

do not chain verification of signers certificates that is don't use the certificates in the signed message as untrusted CAs.

normally when a message is signed, a set of attributes are included which include the signing time and the supported symmetric algorithms. With this option they are not included.

If the outfilename is specified, it should be a string holding the name of a file into which the certificates of the persons that signed the messages will be stored in PEM format.

Note that PHP internally stores integral values as signed. If you unpack a large unsigned long and it is of the same size as PHP internally stored values the result will be a negative number even though unsigned unpacking was specified.

Also note that PHP internally stores integer values as signed values of a machine dependent size. If you give it an unsigned integer value too large to be stored that way it is converted to a float which often yields an undesired result.