Asymmetric cryptography, or public-key cryptography, is the foundation of security protocols that do not require shared secrets. Asymmetric cryptography uses key pairs: a public key and a private key. For example, a protocol that requires data confidentiality can encrypt with the public key and decrypt with the private key. A protocol that requires data authenticity can sign with the private key and verify with the public key.

Use this tag for questions about choosing and understanding protocols based on public-key cryptography algorithms, such as rsa, dsa, diffie-hellman, etc. Other related tags include key-management and public-key-infrastructure.