Public Key Cryptosystem

Definition ∞ A public key cryptosystem, also known as asymmetric cryptography, uses a pair of mathematically linked keys for encryption and decryption or for digital signatures. One key, the public key, can be freely shared, while the other, the private key, must be kept secret by its owner. This system allows anyone to encrypt a message for the private key holder using their public key, or to verify a digital signature created by the private key holder. It forms the backbone of secure communication and identity verification in blockchain networks.
Context ∞ Public key cryptosystems are fundamental to the operation of nearly all cryptocurrencies and blockchain technologies, enabling secure transactions and user authentication. The security of digital wallets and the integrity of blockchain records depend entirely on the strength and proper management of these key pairs. The ongoing development of post-quantum cryptography seeks to replace existing public key systems with quantum-resistant alternatives to maintain long-term security.