mudra
post-quantum cryptographic primitives for neurons. mudra (मुद्रा — seal/gesture in Sanskrit) is to neurons what hemera is to particles: hemera gives content its identity and integrity (hashing, commitment, tree proofs); mudra gives agents their confidentiality and privacy (encrypting, exchanging keys, computing privately, distributing keys).
hemera answers: what exists, and how to verify it. mudra answers: who acts, and how to protect them.
why no signatures or VRF
in a proof-native system, stark proofs replace both. a neuron proves H(secret) = address in zero knowledge — this IS a signature, just a more powerful one. every digital signature is a special case of a zero-knowledge proof of knowledge. similarly, a VRF computes output = H(secret, input) and proves correctness — the proof system handles this directly.
what proofs provide that signatures cannot: composability (prove arbitrary statements, not just key ownership), chargeability (every proof is metered), and universality (one mechanism for authentication, integrity, randomness, and metering).
the call mechanism in nox (pattern 16) makes this concrete: a neuron proves knowledge of its secret key without revealing it, both on-chain and off-chain. every message is proved and charged for — proof of delivery replaces signed delivery.
the separation
proofs (zheng) handle: authentication, integrity, randomness, metering. mudra handles: confidentiality, key agreement, private computation, key distribution.
these are orthogonal concerns. proofs verify and charge; mudra hides and shares.