# What is Deterministic Authenticated Encryption?

I came across something known as deterministic authenticated encryption in my studies and a lot of people were associating it with Synthetic IV mode.

I am having trouble what exactly DAE is because I thought that if something was deterministic then it didn't have a sense of authenticated encryption as it violates the confidentiality of the message -- deterministic encryption modes are prone to CPA attacks.

Can someone explain in layman's terms what exactly DAE is? How does DAE differ from just normal deterministic encryption modes like ECB mode?

• In layman's terms, it's exactly what it sounds like. ​ It's supposed to provide $\hspace{1.79 in}$ the deterministic version of confidentiality. ​ ​ ​ ​ – user991 Mar 15 '16 at 12:19
• Are we talking about (fully) nonce misuse resistant authenticated encryption (like SIV) here or simple (stateful) nonce-based authenticated encryption (like GCM)? – SEJPM Mar 15 '16 at 13:10
• Opposite to nonce based authenticated encryption, DAE takes as input only the associated data, the plaintext and the key and outputs a ciphertext. SIV is a good example of this. The point is to use such primitives in a context where the use of a IV is rendered irrelevant because the plaintext distribution is of high entropy (such as key encryption) – Alexandre Yamajako Mar 15 '16 at 13:18