AdaCore Blog

4 entries tagged with #Cryptography

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