System and method for generating, disseminating, controlling, and
processing limited-life security codes used to authenticate users, particularly for electronic financial transactions, such as
payment transactions or interacting with automated teller machines and the like. Providing a user with a single security code
usable across multiple accounts or other secured systems is contemplated, each security code having a limited lifetime (e.g., one day). In a particular example of the present invention, a plurality of similarly situated users (each needing authenticated access to a plurality of accounts or other secured systems using the security code) are each assigned a set or group of respective security codes. In a preferred example, each security code is a random number from a random
number generator. The respective security codes for each user correspond to a respective security code validity period of limited duration. Thus, a table or matrix that associates the plurality of users with the respective sets of randomly selected security codes (each having their respective validity periods) is generated, and that matrix is provided to the respective entities (such as banks,
payment processors, computer networks generally, etc.) to which each user requires secured access. In parallel, at least a current security code (for example, for the current validity period) is provided to each user, and this is how the respective entities being accessed can track which code from which user is currently valid.