10 entries tagged with #Cryptography

by Daniel King

Avoiding Vulnerabilities in Crypto Code with SPARK

Writing secure software in C is hard. It takes just one missed edge case to lead to a serious security vulnerability, and finding such edge cases is difficult. This blog post discusses a recent vulnerability in a popular SHA-3 library and how the same problems were avoided in my own SHA-3 library written in SPARK.

#Security #SPARK #Cryptography #Formal Verification

by Yannick Moy

SPARKNaCl - Two Years of Optimizing Crypto Code in SPARK (and counting)

SPARKNaCl is a SPARK version of the TweetNaCl cryptographic library, developed by formal methods and security expert Rod Chapman. For two years now, Rod has been developing and optimizing this open-source cryptographic library while preserving the automatic type-safety proof across code changes and tool updates. He has recently given a talk about this experience that I highly recommend.

#SPARK #Cryptography #Formal Verification

by Roderick Chapman

SPARKNaCl with GNAT and SPARK Community 2021: Port, Proof and Performance

This post continues our adventures with SPARKNaCl - our verified SPARK version of the TweetNaCl cryptographic library. This time, we'll be looking at yet more performance improvement via proof-driven "operator narrowing", porting the library to GNAT Community 2021, and the effect that has on proof and performance of the code.

#SPARK #Cryptography #Formal Verification #Code generation #RISC-V #Security

by Roderick Chapman

Doubling the Performance of SPARKNaCl (again...)

Following my last blog entry, further experiments show how the performance of SPARKNaCl can be doubled (again), plus analysis of worst-case stack usage and code size at all optimization levels.

#SPARK #Cryptography #Formal Verification #Code generation #RISC-V #Security

by Roderick Chapman

Performance analysis and tuning of SPARKNaCl

This blog goes into the details of both measuring and improving the runtime performance of SPARKNaCl on a real "bare metal" embedded target, and comparing results with those for the original "TweetNaCl" C implementation.

#SPARK #Cryptography #Formal Verification #Code generation #RISC-V #Security

by Emma Adby

Make with Ada 2020: CryptAda - (Nuclear) Crypto on Embedded Device

Team CryptAda's project collects entropy, manages an entropy pool, implements a homemade PRNG, and generates RSA keys directly on the board with an accent on security. Additionally, this project won a finalist prize in the 2019/20 Make with Ada competition.

by Roderick Chapman

Proving properties of constant-time crypto code in SPARKNaCl

Over the last few months, I developed a SPARK version of the TweetNaCl cryptographic library. This was made public on GitHub in February 2020, under the 2-clause BSD licence. This blog entry goes into a bit more technical detail on one particular aspect of the project: the challenge of re-writing and verifying "constant time" algorithms using SPARK.

#SPARK #Cryptography #Formal Verification

by Isabelle Vialard

Secure Use of Cryptographic Libraries: SPARK Binding for Libsodium

The challenge faced by cryptography APIs is to make building functional and secure programs easy for the user. In this blog post I will present you how I created a SPARK binding for Libsodium, using strong typing and preconditions/postconditions to enforce a safe and functional use of basic cryptographic primitives.

#SPARK #Security #Cryptography #Binding

by Joffrey Huguet

Using SPARK to prove 255-bit Integer Arithmetic from Curve25519

In 2014, Adam Langley, a well-known cryptographer from Google, wrote a post on his personal blog, in which he tried to prove functions from curve25519-donna, one of his projects, using various verification tools: SPARK, Frama-C, Isabelle... He describes this attempt as "disappointing", because he could not manage to prove "simple" things, like absence of runtime errors. I will show in this blogpost that today, it is possible to prove what he wanted to prove, and even more.

#SPARK #Formal Verification #Cryptography

by Yannick Moy

SPARK 2014 Rationale: Type Predicates

Preconditions and postconditions define a very strong mechanism for specifying invariant properties over the program's control. What about similar properties for the program's data? It turns out Ada 2012 defined such a construct, type predicates, which was not supported in SPARK until now. And now it is.

#Language #Formal Verification #SPARK