Definition ∞ Public-key schemes, also known as asymmetric cryptography, utilize a pair of mathematically linked keys for secure communication. One key, the public key, can be freely distributed, while the other, the private key, must remain secret. Data encrypted with the public key can only be decrypted with the corresponding private key, and vice versa for digital signatures. This system provides confidentiality, authentication, and non-repudiation. It forms the basis of secure online interactions.
Context ∞ Public-key schemes are the backbone of security in modern digital systems, including cryptocurrencies, where they secure transactions and verify ownership of digital assets. A critical discussion involves the vulnerability of current public-key algorithms to quantum computing attacks, which could render them insecure. Extensive research and development are underway to transition to post-quantum cryptographic schemes to protect future digital assets and communications. This transition is a major security imperative.