FROST-Ed25519 Ciphersuite
FROST threshold signature ciphersuite over Ed25519 (RFC 9591 §6.2), used for Lux validator session keys and Solana/Cardano bridge custody on M-Chain.
Implementation status (code-audited 2026-07-03): DESIGN — NOT YET IMPLEMENTED Code ships FROST(Ristretto255, SHA-512) per RFC 9591 §6.1 (threshold/protocols/frost/frost.go:91,159); the Edwards25519 §6.2 ciphersuite this LP specifies does not exist, nor does the claimed package path.
Provenance
Originally LP-7310, renumbered 2026-05-18 to consolidate all cryptographic primitives into the 4xxx range with family sub-ranges (threshold + MPC primitives 4700-4799; FROST ciphersuites at 4711/4712). The 7310 slot is retained as a permanent pointer to this LP.
Abstract
FROST-Ed25519 is the FROST (Flexible Round-Optimized Schnorr
Threshold) ciphersuite over Edwards25519 as standardized in IETF
RFC 9591 §6.2. This LP pins the ciphersuite identifier, the
PRF/hash domain separation tags (FROST-ED25519-SHA512-v1), the
SHA-512 challenge hash binding, the encoding (64-byte compact
signatures matching Ed25519 over the same curve), and the
implementation pointer; the underlying FROST protocol is defined in
LP-7321. Use FROST-Ed25519 for Lux validator session-key threshold
authorization, Solana bridge custody, Cardano bridge custody, and
any consumer expecting RFC-8032 EdDSA-compatible verification.
Output signatures verify with the standard Ed25519 verification
algorithm (LP-3654 precompile), so on-chain verifiers do not need
threshold-specific support.
Reference implementation
- Primitive:
luxfi/threshold/frost/ed25519 - Verification: LP-3654 (Ed25519 / EdDSA precompile)
- Chain home: LP-7100 (M-Chain)
- Test vectors: RFC 9591 §6.2
Copyright
Copyright and related rights waived via CC0.