Public Key Cryptography
Noun · Security & Infosec
Definitions
An encryption system using mathematically linked key pairs: a public key (shared openly) for encryption/verification and a private key (kept secret) for decryption/signing. Solves the key distribution problem — you can send encrypted messages without first sharing a secret. The foundation of TLS, SSH, GPG, and digital signatures.
In plain English: An encryption system with two keys — one public for locking, one private for unlocking — so you can communicate securely with strangers.
Example: "SSH authentication uses public key crypto — your public key goes on the server, your private key stays on your machine. No password needed."
Etymology
- 1976
- Diffie and Hellman published 'New Directions in Cryptography,' introducing the concept of public key exchange.
- 1977
- Rivest, Shamir, and Adleman created RSA, the first practical public key cryptosystem.
Related Terms
- Homomorphic Encryption
- Post-Quantum Cryptography
- Bitlocker
- Block Cipher
- Ciphertext
- Cleartext
- Crypto Agility
- Cryptanalysis
- Cryptojacking Attack
- DES
- Disk Encryption
- Encryption at Rest
- Entropy Analysis
- GnuPG
- Hash Extension Attack
- Hybrid Encryption
- Key Rotation
- Keystroke Injection
- PBKDF2
- PGP
- Stream Cipher
- Temporal Key Integrity Protocol
- AES
- AES-256
- Asymmetric Key
- Attribute-Based Encryption
- Blowfish
- Cloud Key Management
- Decryption
- DoT
- IV
- Key Length
- Key Wrapping
- Null Cipher
- Plaintext Attack
- Point-to-Point Encryption
- Post-Quantum