This project might be open to known security vulnerabilities, which can be prevented by tightening the version range of affected dependencies. Find detailed information at the bottom.

Crate x25519-dalek

Dependencies

(4 total, 1 possibly insecure)

CrateRequiredLatestStatus
 curve25519-dalek ⚠️^44.1.3maybe insecure
 rand_core^0.60.6.4up to date
 serde^11.0.203up to date
 zeroize^11.8.1up to date

Dev dependencies

(3 total, all up-to-date)

CrateRequiredLatestStatus
 bincode^11.3.3up to date
 criterion^0.50.5.1up to date
 rand_core^0.60.6.4up to date

Security Vulnerabilities

curve25519-dalek: Timing variability in `curve25519-dalek`'s `Scalar29::sub`/`Scalar52::sub`

RUSTSEC-2024-0344

Timing variability of any kind is problematic when working with potentially secret values such as elliptic curve scalars, and such issues can potentially leak private keys and other secrets. Such a problem was recently discovered in curve25519-dalek.

The Scalar29::sub (32-bit) and Scalar52::sub (64-bit) functions contained usage of a mask value inside a loop where LLVM saw an opportunity to insert a branch instruction (jns on x86) to conditionally bypass this code section when the mask value is set to zero as can be seen in godbolt:

A similar problem was recently discovered in the Kyber reference implementation:

https://groups.google.com/a/list.nist.gov/g/pqc-forum/c/hqbtIGFKIpU/m/cnE3pbueBgAJ

As discussed on that thread, one portable solution, which is also used in this PR, is to introduce a volatile read as an optimization barrier, which prevents the compiler from optimizing it away.

The fix can be validated in godbolt here:

The problem was discovered and the solution independently verified by Alexander Wagner [email protected] and Lea Themint [email protected] using their DATA tool:

https://github.com/Fraunhofer-AISEC/DATA