Multikey <2025>

⭐⭐⭐⭐ (4/5) for multisig; ⭐⭐⭐ (3/5) for niche protocols like MK-TESLA – strong but requires expertise. 4. Multikey Hardware (YubiKey-like, GPG smartcards) Definition: A single hardware token that can store and use multiple independent key pairs (e.g., PIV slots, GPG keys for different purposes, FIDO2 resident keys).

❌ Complexity – key management, coordination overhead ❌ Larger signatures or additional rounds of communication ❌ Not standardized across all systems

If you had a specific software or protocol in mind (e.g., “multikey in Redis” or “multikey in AWS KMS”), let me know and I’ll narrow the review. multikey

❌ Key management becomes complex – which slot holds which key? ❌ Some software assumes one key per token ❌ Limited storage (e.g., YubiKey 5 holds ≤ 25 resident FIDO2 keys)

Definition: A multikey index is an index on an array field in a document database (e.g., MongoDB). Each value in the array gets a separate index entry pointing to the same document. ⭐⭐⭐⭐ (4/5) for multisig; ⭐⭐⭐ (3/5) for niche

❌ Standard library often missing (C++, Java, Python need custom or third-party) ❌ Memory overhead for multiple key mappings if done naively

Tagging systems, permissions lists, event participants, any “many-to-many” flattened into a document. ❌ Complexity – key management, coordination overhead ❌

❌ Only one array field per compound index (MongoDB limitation) ❌ Index size can explode if arrays are huge (each element → one index entry) ❌ Performance degrades with very high cardinality arrays (many unique values per document)