ISO/IEC 9797-1:2011 specifies six MAC algorithms that use a secret key and an n-bit block cipher to calculate an m-bit MAC. ISO/IEC 9797-1:2011 can be applied to the security services of any security architecture, process, or application. Key management mechanisms are outside the scope of ISO/IEC 9797-1:2011. ISO/IEC 9797-1:2011 specifies object identifiers that can be used to identify each mechanism in accordance with ISO/IEC 8825-1. Numerical examples and a security analysis of each of the six specified algorithms are provided, and the relationship of ISO/IEC 9797-1:2011 to previous standards is explained.