1. A method for secure electronic commerce transaction executed by a computer, the method comprises: receiving, via computer interface of the computer, account information regarding an electronic commerce transaction; generating, by a processing module of the computer, a transaction authorization request message based on the account information, transaction information, and merchant information; encoding, by a processing module of the computer, the transaction authorization request message in accordance with an error coding dispersed storage function to produce a plurality of encoded data slices; outputting, via the computer interface, the plurality of encoded data slices to a plurality of dispersed storage units in accordance with an authorization protocol; receiving, via the computer interface, at least a threshold number of encoded data response slices from the plurality of dispersed storage units in accordance with the authorization protocol; and decoding, via the processing module, the plurality of encoded data response slices in accordance with the error coding dispersed storage function to produce a response message.