Opening

I am me and I am Jasmin/EC user

I got great help in preparing the talk from developers and they are in chat

Show what to expect slide.

Structure:

• Quick look at example
• A brief look at how Jasmin works
• Security proofs and correctness proofs in EasyCrypt

Quick look at example

Show diagram

Show slide about AES NI and AES in Jasmin

Show Jasmin code (both mem and reg)

Show how both can be called from C

Show safety check

Show constant-time, explain what it means and how it is checked

Jasmin

Phylosophy:

• quasm inspired: more usable than assembly but still control (side effects explicit, flags)

• verification perspective:

  • well defined semantics (two of them)
  • source level semantics (arrays as collections, loops, function calls)
  • verification close to structured languages such as C

• assembly in the head/control:

  • predict in your head what will come out
  • compiler is thin (can prove constant-time preservation)
  • a lot is left to the programmer (spilling, make sure register assignment exists)

Look at code AES

• explain exported functions vs inlineable functions
• high-level and low-level syntax (arrays, if, loops, functions vs registers, direct asm)
• show assembly and explain the context of in-the-head: unroll, inlined int
• explain stack, show stack code (explain that compiler takes control of stack)
• mention interpreter

Proof

Show example slide, crypto spec => corresponding EC specification.

Show IND$-CPA, PRF and limitations => RFth, RPth, PRFth, NbEnc.

Show cheat sheet and explain that it shows main rules.

Show scheme, correctness and brush over proof.

Implementation security

Show slides and discuss what it means.

Extraction, show results:

• Explain TCB (EC semantics for Jasmin match Coq, Coq semantics itself, plus extraction tool and EC itself)

• Explain AES_spec (operator) and what is proved about it

• Show how example uses AES and how one can recover the AES result as op

Proof of correctness:

• Highlight refined scheme uses AES op as f (assumption)

• Highlight refined scheme has same types, so we have a special case which is nice