Epic: Improvements from FROST Audit

[mpguerra]

Motivation

We want to ensure that we track and act upon findings from the audit.

Scope

frost-core

• [x] #442
  • fixed in #452
• [x] #443
  • fixed in #453
• [x] #455
  • fixed in #480
• [x] #456
  • fixed in #481
• [x] #457
  • fixed in #477

frost-ed25519

No findings

frost-ed448

• [x] NCC-E008263-72Y: Ed448 Base Field Incorrect Negation
  • Fixed in https://github.com/crate-crypto/Ed448-Goldilocks/issues/28 by https://github.com/crate-crypto/Ed448-Goldilocks/pull/29, and
  • in https://github.com/mit-plv/fiat-crypto/issues/1620 by https://github.com/mit-plv/fiat-crypto/pull/1623
• [x] NCC-E008263-T3P: Potential Timing Attacks in Ed448 Implementation
  • Fixed in https://github.com/crate-crypto/Ed448-Goldilocks/issues/30 by https://github.com/crate-crypto/Ed448-Goldilocks/pull/31
• [x] NCC-E008263-HGL: Lack of Zeroization in Ed448 Scalar Inversion
  • Fixed in https://github.com/crate-crypto/Ed448-Goldilocks/issues/32 by https://github.com/crate-crypto/Ed448-Goldilocks/pull/33

frost-p256

No findings

frost-secp256k1

No findings

frost-ristretto255

No findings

Optional Tasks

Other miscellaneous remarks that are not considered security vulnerabilities. Fixing these could increase code quality.

• General Notes on frost-core
  • [x] #458
    • fixed in #482
  • [x] #459
    • fixed in #483
  • [x] #460
    • fixed by #481
  • [x] #461
    • fixed by #494
  • [x] #462
    • fixed by #484
  • [x] #463
    • fixed in #485
  • [x] #464
    • fixed in #485
  • [x] #465
    • fixed in #496
• Notes on RedDSA
  • No Action: We acknowledge the comment and have an explanation for the discrepancies.
• Observations on Batch Verification
  • [x] #444
  • [x] #445
    • fixed in #487
  • [x] #446
    • fixed in #487
• Notes on the Different FROST Versions
  • [x] #447
    • fixed in #488
  • [x] Update CONTEXT_STRING values to match latest spec
    • fixed in #438
• Notes on the IETF Draft
  • [x] https://github.com/cfrg/draft-irtf-cfrg-frost/issues/445 - fixed by https://github.com/cfrg/draft-irtf-cfrg-frost/issues/448
  • [x] https://github.com/cfrg/draft-irtf-cfrg-frost/issues/446 - fixed by https://github.com/cfrg/draft-irtf-cfrg-frost/issues/447
  • [x] https://github.com/cfrg/draft-irtf-cfrg-frost/issues/453 - fixed by https://github.com/cfrg/draft-irtf-cfrg-frost/issues/456
• Minor Documentation Notes on the Source Code
  • [x] #448
    • fixed in #489
    • There's one outstanding TODO in the code which is still waiting for div_ceil to make it into stable rust
• Notes on the FROST Book
  • [x] #466
    • fixed in #491

[mpguerra]

All done here!