Threshold Cryptography.

A class of cryptographic schemes in which a secret key is split across n parties so that any t of them — but no smaller subset — can sign, decrypt, or perform any other key operation. It belongs to the Cryptography category of cybersecurity.

A class of cryptographic schemes in which a secret key is split across n parties so that any t of them — but no smaller subset — can sign, decrypt, or perform any other key operation.

Threshold cryptography distributes a cryptographic capability — typically signing, decryption, or key generation — across n participants such that any t-of-n can collaborate to perform the operation while up to t-1 corrupted parties learn nothing. Constructions rely on secret sharing (Shamir, Feldman, Pedersen), threshold variants of RSA, ECDSA, EdDSA, BLS, or lattice-based schemes, and frequently use MPC to compute the protocol without ever reconstructing the secret. NIST is currently standardizing threshold cryptography through its NIST IR 8214 series. Real-world uses include key management for custodial wallets, distributed certificate authorities, threshold validators on proof-of-stake blockchains, and protection of high-value HSM keys.

Defences for Threshold Cryptography typically combine technical controls and operational practices, as detailed in the full definition above.

Common alternative names include: Threshold signing, Distributed key cryptography.