Systems and methods are described for distributing and updating trusted certification authorities to computer systems and users. When a digital certificate is encountered during a secured electronic transaction, the root authority of the certificate is determined. It is then determined whether the root authority is a trusted authority by attempting to locate the root authority in a trusted root list. If the root authority is not included in the trusted root list, a remote site is accessed and an updated version of the trusted root list is downloaded. The new trusted root list is checked for the presence of the encountered certificate and, if found, the transaction is allowed to proceed. In one implementation, the entire trusted root list is not downloaded. Instead, if an appropriate digital certificate is located, then the certificate is downloaded and added to the trusted root list of the computer system. The transaction may then proceed.