Secret Suffix MAC

A method of implementing MAC with $\text{MAC}(\text{message},\text{key})=\text{Hash}(\text{message}||\text{key})$

Formal Definition

$m=h(x||k)=h(x_1||\dots ||x_n||k)$

• In case of message $x$ being larger than blocksize (like 512 for SHA)

Vulnerabilities

• Secret Suffix Forgery Attack