BBS+ Signatures vs EdDSA: Selective Disclosure for VCs

Core advantage: Enables deriving a zero-knowledge proof from a single multi-claim signature. Users can reveal only specific attributes (e.g., age > 21) without exposing the entire credential or the issuer's signature. This is critical for privacy-preserving KYC and minimal disclosure use cases.

Key trade-off: Signing and verification are ~100-1000x slower than EdDSA due to complex pairing-based cryptography. This impacts high-throughput issuance (e.g., event tickets) and mobile/WASM environments. Libraries like @mattrglobal/bbs-signatures are less battle-tested than EdDSA's libsodium.

Core advantage: Sub-millisecond signing/verification and minimal bandwidth. It's the industry standard (used by Solana, Discord, SSH) with mature, audited libraries in every language. Ideal for high-volume, low-latency scenarios like NFT badges or IoT device attestation.

Key trade-off: To verify any claim, you must present the entire signed credential. This forces data minimization compromises, requiring workarounds like blinded signatures or multiple single-claim VCs, which increase complexity and issuer load. Not natively compatible with W3C Selective Disclosure standards.

Selective Disclosure: A single BBS+ signature allows a holder to reveal only specific claims (e.g., age > 21) without exposing the entire credential. This enables privacy-preserving proofs and is the foundation for W3C's Data Integrity BBS+ Cryptosuites.

Multi-Message Binding: One signature can securely bind dozens of claims, reducing on-chain footprint for credential issuance and verification. This is critical for complex credentials like educational transcripts or employment history in protocols like AnonCreds.

Performance & Maturity: EdDSA (Ed25519) is a battle-tested standard with ~100k TPS signing/verification speeds. It's natively supported by most wallets, blockchains (Solana, Algorand), and libraries, leading to faster integration and lower computational overhead.

Wallet & Chain Compatibility: Direct support in Ledger, Keplr, and Phantom wallets. Ideal for VC use cases where the credential must be signed/verified directly on-chain (e.g., token-gating with SBTs) or within established ecosystems like Cosmos IBC.

Computational Cost: Verification is ~100-1000x slower than EdDSA, requiring more complex zero-knowledge proof systems. This can be a bottleneck for high-throughput or mobile applications unless optimized with BLS12-381 pairings.

All-or-Nothing Disclosure: To prove one claim, you must present the entire signed credential, leaking all other attributes. This fails core privacy requirements for decentralized identity (DID) systems like verifiable presentations in SSI architectures.

Performance & Ubiquity: Benchmarks show Ed25519 signatures are ~10x faster to generate and verify than BLS or RSA. It's natively supported in major crypto libraries (libsodium, OpenSSL) and blockchains (Solana, Algorand). This matters for high-throughput, low-latency systems like on-chain identity checks.

No Selective Disclosure: To verify a single claim (e.g., age > 21), the entire credential must be revealed, creating privacy leaks. This forces a trade-off: either disclose all data or issue multiple single-claim credentials, increasing issuer load and verifier complexity.

Zero-Knowledge Selective Disclosure: A holder can cryptographically prove selective claims (e.g., citizenship) from a multi-claim VC without revealing the signature or other data. This enables privacy-preserving Presentation Layer protocols essential for W3C VCs and decentralized identity (DIDComm).

Performance & Immaturity: Signing/verification is ~100-1000x slower than Ed25519. Library support is nascent (e.g., bbs-signatures in Rust/JavaScript). This matters for mobile wallets or systems requiring sub-second verification. The cryptographic complexity also increases audit and implementation risk.