Cryptography in coherent optical information networks using dissipative metamaterial gates

Angelos Xomalis,Iosif Demirtzioglou,Yongmin Jung,Periklis Petropoulos,Cosimo Lacava,David J Richardson,Eric Plum,Nikolay I Zheludev

doi:10.1063/1.5092216

Angelos Xomalis, Iosif Demirtzioglou + Show 6 more

Open Access

https://doi.org/10.1063/1.5092216

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Abstract

All-optical encryption of information in fibre telecommunication networks offers lower complexity and far higher data rates than electronic encryption can deliver. However, existing optical layer encryption methods, which are compatible with keys of unlimited length, are based on nonlinear processes that require intense optical fields. Here, we introduce an optical layer secure communication protocol that does not rely on nonlinear optical processes but instead uses energy redistribution of coherent optical waves interacting on a plasmonic metamaterial absorber. We implement the protocol in a telecommunication optical fibre information network, where signal and key distribution lines use a common coherent information carrier. We investigate and demonstrate different encryption modes, including a scheme providing perfect secrecy. All-optical cryptography, as demonstrated here, exploits signal processing mechanisms that can satisfy optical telecom data rate requirements in any current or next-generation frequency band with bandwidth exceeding 100 THz and a switching energy of a few photons per bit. This is the first demonstration of an optical telecommunications application of metamaterial technology.

Highlights

Secure exchange of confidential information is essential in banking, health care, social media, the Internet of Things, government, the security forces, and many other aspects of modern life
Eve could only decrypt the data by simultaneously reading encrypted data and key including their mutual phase. This would be a complex task as these are sent along different fibres in our implementation. (As in other one-time pad encryption systems, this vulnerability could be avoided by using pre-shared keys: Bob could apply a preshared key bit sequence to an unmodulated Continuous Wave (CW) laser signal sent by Alice.) Suitable, truly random key bit sequences can be generated at up to 300 Gbit/s based on the output of chaotic semiconductor lasers
We have shown how the phase of mutually coherent information carriers can be exploited for cryptography in coherent scitation.org/journal/app information networks

Summary

INTRODUCTION

Secure exchange of confidential information is essential in banking, health care, social media, the Internet of Things, government, the security forces, and many other aspects of modern life. More widely-used encryption techniques use keys of limited length, making them vulnerable to brute force attacks Symmetric techniques, such as Data Encryption Standard (DES) and Advanced Encryption Standard (AES), use the same key for encryption and decryption and require secure key distribution, e.g., quantum key distribution.. The proposed encryption protocol is applicable to any wave information carrier in a network containing mutually coherent communication lines. It is a symmetric, one-time pad technique without significant computational cost and immediate signal recovery. Such optical implementations have the potential to provide perfect secrecy with THz bandwidth and low power consumption

COHERENT CRYPTOGRAPHY CONCEPT

EXPERIMENTAL DEMONSTRATION OF COHERENT CRYPTOGRAPHY

PERFECT SECRECY SCHEME

Findings

CONCLUSIONS