What question did this study set out to answer?

The aim is to develop transaction signatures that resist forgery even from powerful adversaries while ensuring policy compliance on the blockchain.

April 20, 2026Open Access

DSKAG-IT-SIG: Information-Theoretic Transaction Signatures with Hardware-Bound Policy Binding and Permissionless Zero-Knowledge On-Chain Verification

Key Points

The aim is to develop transaction signatures that resist forgery even from powerful adversaries while ensuring policy compliance on the blockchain.
Developed DSKAG-IT-SIG, combining information-theoretic principles and transaction signature schemes.
Utilized DSKAG for key generation without key transmission or handshake.
Implemented a four-layer zero-knowledge proof system enabling on-chain compliance verification.
Achieved unconditional existential unforgeability against unbounded adversaries under ideal conditions.
Demonstrated significant size reduction in signatures (97.8% smaller than Falcon-512).
Validated by three independent institutions with no found structural attacks.

Abstract

We present DSKAG-IT-SIG, a family of information-theoretic transaction signature schemes that achieve unconditional existential unforgeability under adaptive chosen-message attack by computationally unbounded adversaries. The construction derives per-transaction MAC keys through DSKAG, a deterministic symmetric key agreement protocol requiring no key transmission, no handshake, and no public key infrastructure. We prove (Theorem 1) that the forgery advantage of any unbounded adversary making q queries is at most q * 2^-128 in standard mode under the ideal cipher model, reducing to the statistical uniformity of DSKAG-derived keys and the random-function behavior of HMAC-SHA256 under a uniform key. In the standard model, the bound holds up to the PRF distinguishing advantage of HMAC-SHA256. We prove (Theorem 2) that cross-domain forgery advantage is at most 2^-128 + epsilonᵢso, reducing to the statistical key isolation of DSKAG across policy domains. Both bounds are unconditional in the ideal cipher model and independent of any computational hardness assumption. Standard-mode signatures are 30 bytes, a 97. 8% reduction versus Falcon-512 (666 bytes) and compatible with ISO 20022 SWIFT message fields without re-engineering. The NexusKey composite policy digest binds asset class, jurisdiction, KYC level, and chain identity into the key derivation path; policy bypass is cryptographically equivalent to key forgery. A four-layer UltraHonk zero-knowledge proof system (143, 802 gates, no trusted setup, 16 KB proof) enables permissionless on-chain compliance verification, deployed on Ethereum Sepolia and Arbitrum Sepolia. Version 2. 3. 18 pages, 8 tables. Three independent academic institutions validated the construction: no structural attacks found. Changes from v2. 2: concrete finite bounds replacing generic negl (lambda) in Properties 1 and 2; buffer uniqueness derived from txₛeq monotonicity (no SHA3 collision resistance dependency) ; explicit ideal cipher model and standard model dual framing for HMAC analysis; formal separation of empirical and theoretical claims.

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