SQIsign2D2
Isogenies · niccs.org.cn(opens in a new tab)
- Programmes
- NGCC R1
- Latest version
- Round 1 ·
- Security flags
- Broken (all sets) · Implementation findings (1 of 6 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 |
|---|---|---|---|---|---|---|
| SQISign2Dsquare-Level2-eff BrokenImplementation findings | 128-bit | 80 | 248 | 328 | 31.24 ms | 6.30 ms |
| SQISign2Dsquare-Level2-sec Broken | 128-bit | 84 | 260 | 344 | 37.50 ms | 7.24 ms |
| SQISign2Dsquare-Level3-eff Broken | 256-bit | 128 | 392 | 520 | 99.89 ms | 20.58 ms |
| SQISign2Dsquare-Level3-sec Broken | 256-bit | 132 | 404 | 536 | 119.66 ms | 22.99 ms |
| SQISign2Dsquare-Level5-eff Broken | 512-bit | 256 | 776 | 1,032 | 715.75 ms | 124.86 ms |
| SQISign2Dsquare-Level5-sec Broken | 512-bit | 268 | 812 | 1,080 | 782.47 ms | 145.90 ms |
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 compact verifier never checks the transmitted challenge against the commitment, so one signature yields forgeries on fresh messages at every parameter set (Feussner).
- Implementation findings (SQISign2Dsquare-Level2-eff): The submitted reference verifier for this set can take its verdict from stale stack memory, accepting forged or all-zero signatures (Saarinen). Full findings report(opens in a new tab)
Only one version of SQIsign2D2 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.
- added to site Update
SQIsign2D-push1/2 and SQIsign2D2 (SQISign2Dsquare): our build now patches the submitted verifiers so that they reject a signature whose final isogeny splitting step fails. The submitted code does not check that step and can then accept an altered signature (reported on ngcc.dev by LK-PQC-Hunter and Saarinen). Valid signatures are not affected.
- New version
Round 1