arXiv:1408.5800 · Fluctuation and Noise Letters

Enhanced Usage of Keys Obtained by Physical, Unconditionally Secure Distributions

Laszlo B. Kish, Claes-Göran Granqvist

Published May 4, 2015• 24 citations

Abstract

Unconditionally secure physical key distribution schemes are very slow, and it is practically impossible to use a one-time-pad based cipher to guarantee unconditional security for the encryption of data because using the key bits more than once gives out statistical information, for example via the known-plain-text-attack or by utilizing known components of the protocol and language statistics. Here, we outline a protocol that reduces this speed problem and allows almost-one-time-pad based communication with an unconditionally secure physical key of finite length. The physical, unconditionally secure key is not used for data encryption but is employed in order to generate and share a new software-based key without any known-plain-text component. The software-only-based key distribution is then changed from computationally secure to unconditionally secure, because the communicated key-exchange data (algorithm parameters, one-way functions of random numbers, etc.) are encrypted in an unconditionally secure way with a one-time-pad. For practical applications, this combined physical/software key distribution based communication looks favorable compared to the software-only and physical-only key distribution based communication whenever the speed of the physical key distribution is much lower than that of the software-based key distribution. A mathematical security proof of this new scheme remains an open problem.

DOI: 10.1142/s0219477515500078

Related papers

Untappable Key Distribution System: a One-Time-Pad Booster

Geraldo A. Barbosa, Jeroen van de Graaf

The One-Time-Pad (OTP) protocol gives unconditional security for the information being encrypted. Correctly implemented, not even an adversary with a quantum computer can crack it. However, the need of sharing in a secure way supplies of symmetric random keys turned the method almost obsolete as a stand-alone method for fast and large volume telecommunication. Basically, this secure sharing of keys and their renewal, once exhausted, had to be done through couriers, in a slow and costly process. This paper presents a solution for this problem providing a fast and unlimited renewal of secure keys: An untappable key distribution system is presented and detailed. This fast key distribution system utilizes two layers of confidentially protection: 1) Physical noise intrinsic to the optical channel that turn the coded signals into stealth signals and 2) Privacy amplification using a bit pool of refreshed entropy run after run, to eliminate any residual information. The resulting level of security is rigorously calculated and demonstrates that the level of information an eavesdropper could obtain is negligible. The random bit sequences, fast and securely distributed, can be used to encrypt text, data or voice.

arXiv:1406.1543Journal of Information Security and Cryptography (Enigma)May 4, 20164 citations

Fundamentals for immediate implementation of a quantum secured Internet

Geraldo A. Barbosa

This work shows how a secure Internet for users A and B can be implemented through a fast key distribution system that uses physical noise to encrypt information transmitted in deterministic form. Starting from a shared secret random sequence between them, long sequences of fresh random bits can be shared in a secure way and not involving a third party. The shared decrypted random bits -encrypted by noise at the source- are subsequently utilized for one-time-pad data encryption. The physical generated protection is not susceptible to advances in computation or mathematics. In particular, it does not depend on the difficulty of factoring numbers in primes. Also, there is no use of Linear Feed Back Shift Registers. The attacker has free access to the communication channels and may acquire arbitrary number of copies of the transmitted signal without lowering the security level. No intrusion detection method is needed.

arXiv:quant-ph/0607093Jul 14, 20060 citations

An Efficient Algorithm on Quantum Computing With Quantum Key Distribution for Secure Communication

Ganapathy Senthil Murugan

Currently many symmetric key cryptographic tools which are known to be quantum-safe. They all share Secret symmetric keys through an untrusted medium which is usually done with public key methods which are prone to quantum attacks. One among the recommended solutions to the key distribution problem is Quantum Key Distribution (QKD). QKD utilizes an authenticated Communication channel along with a quantum communication channel so that a secret key is generated. Whatever may be the protocol to implement proposed QKD, they all need both a quantum channel, and an authenticated classical. OTP (One Time Pad) is used when two parties wish to communications have to share a key called pad. This pad is a randomly generated key and the length of the key should be equal to the message so it can be sent. The proposed QKD parameters that result in almost 35.67% smaller keys for quantum security and an implementation of QKD in network which is publicly available and usable in practice.

International journal of communicationMay 14, 20202 citations

A WIRELESS SECURE KEY DISTRIBUTION SYSTEM WITH NO COURIERS: A ONE-TIME-PAD REVIVAL

Geraldo A. Barbosa

Among the problems to guarantee secrecy for in-transit information, the difficulties involved in renewing cryptographic keys in a secure way using couriers, the perfect secrecy encryption method known as One-Time-Pad (OTP) became almost obsolete. Pure quantum key distribution (QKD) ideally offers security for key distribution and could revive OTP. However, special networks that may need optical fibers, satellite, relay stations, expensive detection equipment compared with telecom technology and the slow protocol offer powerful obstacles for widespread use of QKD. Classical encryption methods flood the secure communication landscape. Many of them rely its security on historical difficulties such as factoring of large numbers - their alleged security sometimes are presented as the difficulty to brake encryption by brute force. The possibility for a mathematical breakthrough that could make factoring trivial are poorly discussed. This work proposes a solution to bring perfect secrecy to in-transit communication and without the above problems. It shows the key distribution scheme (nicknamed KeyBITS Platform) based on classical signals carrying information but that carry with them recordings of quantum noise. Legitimate users start with a shared information of the coding bases used that gives them an information advantage that allows easy signal recovery. The recorded noise protects the legitimate users and block the attacker's access. This shared information is refreshed at the end of each batch of keys sent providing the secret shared information for the next round. With encryption keys distilled from securely transmitted signals at each round OTP can be revived and at fast speeds.

arXiv:1901.05324Journal of Information Security and Cryptography (Enigma)Jan 27, 20190 citations

Secure sharing of random bits over the Internet

Geraldo A. Barbosa

Although one-time pad encrypted files can be sent through Internet channels, the need for renewing shared secret keys have made this method unpractical. This work presents a scheme to turn practical the fast sharing of random keys over arbitrary Internet channels. Starting with a shared secret key sequence of length K_0 the users end up with a secure new sequence K >> K_0. Using these sequences for posteriori message encryption the legitimate users have absolute security control without the need for third parties. Additionally, the security level does not depend on the unproven difficulty of factoring numbers in primes. In the proposed scheme a fast optical random source generates random bits and noise for key renewals. The transmitted signals are recorded signals that carries both the random binary signals to be exchanged and physical noise that cannot be eliminated by the attacker. These signals allow amplification over the Internet network without degrading security. The proposed system is also secure against a-posteriori known-plaintext attack on the key. Information-theoretic analysis is presented and bounds for secure operation are quantitatively determined.

arXiv:0705.2243May 15, 20070 citations

Practical Implementation of Unconditionally Secure File Transfer Application with QKD and OTP

Alin-Bogdan Popa, Bogdan-Călin Ciobanu, Pantelimon George Popescu

With the looming threat of quantum computers capable of breaking classical encryption and the uncertainty regarding the security of post-quantum encryption algorithms, some highly sensitive applications aim for the highest level of security in information transfer: unconditional security. In this work we present an architecture and a practical implementation of a user-friendly unconditionally secure file transfer client based on quantum key distribution and one time pad cipher. We test the implementation on the live QKD research infrastructure within POLITEHNICA Bucharest, thus proving the approach is feasible for real information transfer use-cases.

Quantum ReportsMar 14, 20250 citations