Secure Comparator

Cossack Labs Blog

27 Jul 2016

Zero Knowledge Protocols without magic

In this post, we talk about Zero-Knowledge Proofs, tie ZKP authentication to traditional security models and help you understand better how authentication, in general, should work. 


7 Apr 2016

Benchmarking Secure Comparator

This post summarizes our experiences of testing Secure Comparator as an authentication mechanism for HTTP.

While we were planning, designing and implementing Comparator, real infrastructure in which it has to function (letting Toughbase instances without shared trust to be able to exchange records and request personal data safely) was very far from being ready, but we wanted to understand how good it was for some practical applications. So we chose the obvious - seeing how SC could work as HTTP authentication mechanism.


11 Feb 2016

Fixing Secure Comparator

After publishing Secure Comparator paper, we've received a number of concerns from the cryptographic community about possible security breach, in case, where one of the parties is intentionally falsifying the protocol. We've adressed these concerns, and, in this blog post and paper update would like to elaborate how and why. 


9 Dec 2015

Introducing Secure Comparator

Secure Comparator is a novel authentication technique we're proposing the cryptographic community to evaluate. It can be used as any id/secret pair authenticator in environments, where no trust relationships exist between two parties.


26 Nov 2015

Why we need novel authentication schemes?

Current technological advancements in authenticating users seems to be sufficient for most cases. However, taking a more detailed look reveals weaknesses and tradeoffs in all existing authentication schemes. Before explaining the methodology and cryptography behind Secure Comparator, our authentication protocol, we wanted to outline reasons for developing it in a brief review of existing authentication methods.


18 Nov 2015

Armoring ed25519 to meet extended security challenges

When developing new, advanced features of Themis library, we had to extend some of the ECC cryptography available in open source with our own implementation to provide simple point multiplication with random (unknown in advance) point. To achieve that, we've extended Daniel J. Bernstein's implementation of ed25519 with our own math and code. This blog post outlines our direction of thinking.


22 Sep 2015

Notes on adding cutting edge features

Some important notes on intruducing experimental, bleeding edge features to Themis, changes in Themis build system in the regard of these features, and a tease of new things to come.


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