How Many Post-Quantum Signatures Fit in a QSOLANA Transaction?
Balance asked what post-quantum signatures do to Solana’s transaction size. BB84’s test network shows why even a 4,096-byte limit can be tight.
Crypto researcher Balance asked how many post-quantum signatures could fit in a Solana transaction after BB84 opened its experimental QSOLANA network on November 13. The test network's larger transaction format has room for one standard ML-DSA-44 signature, but two would exceed the limit before adding any other transaction data.
curious what the PQ signature checks do to Solana's tx size limit. one signature per tx for now?
— Balance (@balance0014) November 13, 2026
How much fits in 4,096 bytes?
Solana's transaction documentation lists a 1,232-byte limit and 64 bytes for each standard Ed25519 signature. BB84's test network accepts up to 4,096 bytes in its version 1 transaction format. An ML-DSA-44 signature takes up 2,420 bytes under NIST's standard. Two take up 4,840 bytes, 744 more than the test network allows.
BB84 reports that its example withdrawal using ML-DSA-44 fits in a 2,688-byte transaction. An ML-DSA-65 signature alone takes 3,309 bytes, leaving 787 for everything else. The 4,627-byte ML-DSA-87 signature exceeds the limit on its own. BB84's documentation says applications can store that larger signature in an account and have their program read it from there.
What the test network verifies
The fork gives developers a way to test signature checks built into the runtime. A vault can use one of those checks to decide whether to release funds. The outer transaction still uses Ed25519, including the signature from the account that pays the fee. A read-only check by BTC PEERS confirmed that the public test endpoint was responding and that BB84's ML-DSA-44 demo vault program was marked executable.
QSOLANA runs on a single node and resets when its validator build changes. The example gives developers a concrete size budget to work with while they design wallets that need more than one approval.
