Squads Builder Says Falcon-512 Post-Quantum Multisig Voting Has Been Tested on Solana Mainnet

A Squads builder says post-quantum signatures can already approve multisig transactions on Solana SOL$106.84-1.3% mainnet. Sean, a Squads team member who posts on X as @gansersol, wrote on 13 October 2026: "Tested and working on Solana mainnet. Post-quantum signing for voting members of your Squads @multisig using Falcon-512." SolanaFloor described him as a Squads co-founder.

Post-quantum signatures are built to hold up against a future quantum computer strong enough to break Ed25519, the scheme Solana uses to sign transactions today. Falcon-512 is one such scheme.

The mainnet test is Sean's own account. His thread includes no transaction, multisig address or integration code, and nothing has been released to Squads users. He said support is planned for "the next release of our extension, SquadsX", gave no date, and added that "there's still work to do before we roll this out more broadly."

How a Falcon-512 signer becomes a Squads multisig voting member

A multisig is a shared account that acts only when enough of its members approve. Sean said the Falcon-512 design leaves Solana's own signatures and the Squads program alone and adds a verifier in front of one member's seat.

"Rather than replacing Solana's native signatures, we can have a separate program verify a Falcon-512 signature and authorize a PDA to act as a voting member of a Squads multisig," he wrote in the same thread. "To the multisig program, it's simply another authorized member." A PDA, or program derived address, is an account controlled by a program instead of a private key. Squads already accepts PDAs as voting members, which is why Sean said none of this requires rewriting the core Squads program.

For scale, the current Squads V4 multisig program was involved in about 395,000 transactions between 13 September and 12 October 2026, according to Solana Compass program analytics.

Blueshift's Vector program does the on-chain signature verification

The verifier is Vector, a program from Blueshift, the developer group whose sbpf-linker release we covered on 9 October 2026. "For our integration, a member signs using Falcon-512. Vector verifies the signature against the expected digest and authorizes its PDA to participate in the multisig approval flow," Sean wrote. He credited @deanmlittle and @L0STE_ at Blueshift for the work on Vector.

Vector's README describes "a Solana primitive for offchain transaction signing that can be used in place of durable nonce workflows". It lists a Falcon-512 program ID next to Ed25519, Secp256k1 and EIP-191 versions, and marks three other post-quantum schemes as "(local)". The README puts each Falcon-512 signature check at about 184k compute units, Solana's measure of processing work. It lists no audit and does not mention Squads.

A Falcon-512 signature is 666 bytes against 64 for Ed25519, according to Jump Crypto's April 2026 paper on quantum migration, which called Falcon its leading candidate for Solana because it has the smallest signatures among the schemes NIST selected. Falcon is not yet a finished standard: NIST's post-quantum project page says it was "selected for ongoing standardization; that process is underway."

Mixed-scheme approvals and the Ed25519 fee payer limit

Sean's example is a 2-of-3 multisig with two Falcon-512 members and one ordinary Ed25519 key. "Even if Ed25519 were completely compromised by advances in quantum computing, an attacker would still have only one vote, insufficient to reach the approval threshold," he wrote. The example is an illustration, and the thread does not describe a deployed configuration.

He also set out what the design leaves exposed. Every Solana transaction still needs an Ed25519 signature from the fee payer, whatever scheme the voters use. Sean's suggested answer is a separate, rotating fee-payer key funded with only enough SOL to cover fees and holding no authority over the multisig. The thread presents that as an approach and does not say Squads has built it.

"Post-quantum multisig voting doesn't mean every cryptographic component of a Solana transaction suddenly becomes post-quantum resistant," he wrote. In a later reply, Sean agreed with a commenter that hardware wallet makers have yet to support these schemes.

Where this sits next to Quantumglow and Solana's network-level plans

Other post-quantum work on Solana targets the network itself. Anza researchers proposed Quantumglow, a post-quantum version of the Alpenglow consensus design, in July 2026. Anza and Firedancer had each put an initial Falcon implementation in their GitHub repositories by April 2026, Cointelegraph reported, and the Jump Crypto paper proposes a Falcon verification call for smart contracts under SIMD-0416.

The Squads approach needs none of those changes, by Sean's account, because the verification happens inside a program a multisig can opt into. The open items are the ones the thread leaves out: a SquadsX release date, an on-chain record of the test and an audit of the verifier.