Properties used to specify the path to the local ID (certificates) file.
typedef struct _cs_sslid
{
        CS_CHAR     *identity_file;
        CS_CHAR     *identity_password;
} CS_SSLIDENTITY
provides a path to the file containing a digital certificate and the associated private key.
CS_GET only returns the indentity_file used, and only if it is set with CS_CONNECTION.
used to decrypt the private key.