###### Abstract  
The methods proposed in this paper are leveraging Challenge-Response-Pair (CRP) mechanisms that are directly using each digital file as a source of randomness. Two use cases are considered: the protection and verification of authenticity of the information distributed in storage nodes and the protection of the files kept in terminal devices operating in contested zero-trust environments comprised of weak signals in the presence of obfuscating electromagnetic noise. With the use of nonces, the message digests of hashed digital files can be unique and unclonable; they can act as Physical Unclonable Functions (PUF)s in challenge-response mechanisms. During enrollment, randomly selected \"challenges\" result in unique output data known as the \"responses\" which enable the generation and distribution of cryptographic keys. During verification cycles, the CRP mechanisms are repeated for proof of authenticity and deciphering. One of the main contributions of the paper is the development of mechanisms accommodating the injection of obfuscating noises to mitigate several vectors of attacks, disturbing the side channel analysis of the terminal devices. The method can distribute error-free cryptographic keys in noisy networks with light computing elements without relying on heavy Error Correcting Codes (ECC), fuzzy extractors, or data helpers. obfuscation; validation; authentication; digital file; cryptography; electronic noise; challenge; response 2023125313390/axions12060531390/1  
15 April 202315 April 20239 May 2023  
introducing difficulty in the distribution of cryptographic keys without heavy ECC, fuzzy extractors, or data helpers, all of which are leaking information [4; 5; 6]. Blockchain technology with digital signatures offers protection in exposed networks, such as the non-alterability and traceability of chains of transactions [7]. Digital Signature Algorithms (DSAs) further enhance security by associating the blockchains to a set of known users and their public keys [8]. Blockchains with digital signatures are exposed to a variety of possible attacks that introduce risk in validating authenticity, specifically when operating outside a reliable network [9; 10]. Concerns include possible difficulties in verifying the legitimacy of a file, the theft private keys, and blockchains that may be forged by associating altered messages with an altered message digest. To prove the authenticity of a message in zero-trust networks, it is important to add layers of security without imposing excessive computing power consumption. Background information in the area of file verification and distributed networks is presented in refs. [11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21]. In [11], a Challenge Response Authentication (CRA) of physical layers is described to avoid exposing passwords. The work presented in [12] shows the methods to provide verification of information in a ledger. The authors of [12] define a \"cryptographic challenge nonce\" and a protocol that enables third parties to verify information; the technology is based on digital signatures with public/private keys. In [13], document tracking schemes on a distributed ledger [13] are presented and details how to insert unique identifiers and hash values for this tracking; a processor coupled with the storage device is used in the protocols. In [14; 15], the authors present a secure exchange of signed records. These records contain digital signatures of the senders and their public keys, which enhances security. Methods to authenticate data based on proof verification are shown in [16; 17; 18]. Some of the data may be external to the network, protected by a blockchain and DSA with public keys. [PERSON] et al. describe the methods to verify certificates based on blockchains. The system compares the content of a previously known certificate by a financial institution with the content of a certificate obtained at the point of use. [PERSON] et al. describe computationally efficient methods to audit transactions.