Mixmaster

Mixmaster is a software tool used in email systems to generate and validate "message authentication codes" (MACs), which help verify that an email message hasn't been altered during transmission. It implements a cryptographic algorithm called the MD5 hash function, creating a unique digital signature based on the message content. By attaching this signature to the email, recipients can confirm the message’s integrity and authenticity. Essentially, Mixmaster ensures that email messages are secure and trustworthy, preventing tampering or forgery during email exchanges.