CS
Lattices · MLWE/MSIS · niccs.org.cn(opens in a new tab)
- Programmes
- NGCC R1
- Latest version
- Round 1 ·
- Security flags
- Broken (all sets) · Implementation findings (all sets)
Third-party findings: full report on ngcc.dev(opens in a new tab).
Parameter sets
Round 1 · 20 Sep 2026
| Parameter set | Level | pk (B) | sig (B) | pk+sig (B) | Sign | Verify |
|---|---|---|---|---|---|---|
| CS-128 BrokenImplementation findings | 128-bit | 976 | 1,548 | 2,524 | 722.0 µs | 154.4 µs |
| CS-256 BrokenImplementation findings | 256-bit | 1,760 | 3,164 | 4,924 | 3.01 ms | 289.0 µs |
| CS-512 BrokenImplementation findings | 512-bit | 4,288 | 5,975 | 10,263 | 11.14 ms | 946.0 µs |
Wall-clock times vary between runs and machines (CPU frequency scaling, other tenants on cloud VMs); cycle counts are the steadier basis for comparison.
Security flags
- Broken (all parameter sets): The verifier ignores the signs of challenge coefficients, allowing universal forgery below every claimed level (Kwiatkowski). Compressed CS-128 signatures leak an equivalent signing key (Lu and Liu; made practical by Feussner).
- Implementation findings (all parameter sets): The submitted code omits a nonce when sampling secrets, collapsing them to one value and making key recovery cheap (Sun). Signatures are also trivially malleable (Saarinen). 32-bit message lengths let a signature verify on long forged messages (Saarinen). Full findings report(opens in a new tab)
Only one version of CS is recorded, so there is nothing to compare yet.
History
- Update
NGCC round 1: we checked every confirmed critical and high-severity finding on ngcc.dev against our data, and the PKC Forum, the ngcc-harness issues, the public analysis repositories and ePrint for findings ngcc.dev does not list. New broken flags: OPS-DSA, whose specified challenge sampler allows forgery from the public key in 2^39 to 2^90 trials (Xiong and Wang); the compact SQIsign2D2 sets, where one signature yields forgeries on fresh messages (Feussner); BAG-Piglet, whose specified rejection key gives key recovery from decapsulation queries (Saarinen); MAMBA-Viper-384 and -512, whose specification derives every session secret from a 256-bit seed (Saarinen); FlexTree-160, where verifiers that follow the specification accept forgeries after about 2^40 work (Kudinov); TRINE-128, whose specified unsalted round seeds allow forgery in about 2^95 work (Feussner); and UVW-256 signatures, which leak an equivalent signing key as at UVW-128 (Feussner, extended by Saarinen). New warnings: HEP-QC, whose public key is distinguishable from random (Xie), and Rhyme-SHAKE-128, where a signer that follows the specified rejection bound leaks its secret (Feussner). New implementation notes cover rejection keys over the re-encryption (CheetahKEM, LoongKEM), partial FO checks (QUBE), buffer overflows (Amoeba, MORNING-ATLAS), 32-bit message lengths (Aigis-Sig+, CS), message compression and short prehashes (COMPASS-SIG, VDOO, Amoeba), wrapper boundaries and signed-message opening (VDOO, MORNING-ATLAS), malleable encodings (SQIsignTriangle) and fail-open key generation (ZEN). Each flag credits and links its finding.
- New version
Round 1