 Cryptographic protocol

A cryptographic protocol specifies an interaction between parties using cryptographic operations to achieve a security property under stated assumptions. A key-exchange protocol, for example, aims to establish a shared secret while controlling what an adversary can learn or alter. Messages need meanings, order, identities and session context in addition to encryption or signatures. A sound primitive does not by itself make every composition secure: replaying a valid message in the wrong session can break an otherwise plausible exchange. Correctness and security depend on the adversary model and the exact transcript rules.

A cryptographic protocol is a formal set of rules that dictate how data is exchanged and secured between parties using cryptographic techniques. These protocols are designed to ensure confidentiality, integrity, authenticity, and non-repudiation in communications and transactions. Key aspects of cryptographic protocols include: 1. **Encryption**: This involves converting plaintext data into ciphertext to ensure that only authorized parties can read it. Different algorithms, such as AES or RSA, may be used.