The on-chain batch aggregator + compliance oracle for Stellar Private Payments
Prism extends Nethermind's SPP (Nethermind's privacy pools for Stellar): it settles many real private transfers in a single verification with constant verification cost in K, and adds what the base pool lacks: hard in-circuit compliance caps plus auditor selective disclosure, for compliant RWA settlement at scale.
Extends Nethermind Stellar Private Payments · Groth16 over BN254 · K real SPP transfers settled in one verify on testnet
Regulated assets on Stellar are transparent, or permissioned. Not private and compliant.
A real-world-asset issuer today must choose: a transparent ledger anyone can read, or a permissioned pool with no proof of compliance. They can be compliant OR private, never both.
Balances, counterparties and amounts are public. Unacceptable for institutional positions that are legally required to stay confidential.
Privacy without programmatic compliance: no proof that a batch stayed within limits, no auditor-verifiable totals. Regulators can't trust it.
RWA settlement needs both: confidential positions and provable, auditor-checkable compliance, at a cost that scales.
Prism extends Nethermind's Stellar Private Payments.
SPP is a privacy pool for Stellar: real private transfers on Soroban with Groth16/BN254 proofs. Prism builds directly on it (same curve, real SPP transactions) and adds the two things the base pool doesn't have.
- ✓ Private transfers (amounts & relationships hidden)
- ✓ ASP membership / non-membership controls
- · One transfer per verification
- · No in-circuit compliance proof
- · No auditor-verifiable totals
- ＋ Batch aggregation: many real SPP transfers in one verification, constant cost in K
- ＋ Hard compliance caps: total & per-transfer limits enforced as proof constraints
- ＋ Auditor selective disclosure: amounts encrypted on-chain, totals verifiable by the auditor
Crediting and building on SPP; its circuits are vendored (Apache-2.0), not reinvented.
Many private transfers in, one compliant verification out.
K private SPP transfers
Real policy_tx_2_2 witnesses, amounts hidden
Prism aggregation circuit
K transfers + cap predicates + auditor ECDH, one proof
One BN254 verify on-chain
Constant 4 public signals → flat verify cost
Compliance proof + auditor notes
Caps attested; (R, ciphertext) stored, no amounts
Aggregation-by-batching (re-proving real SPP transfers together), not recursive proof verification. The proof is generated offline; the settlement runs live on testnet.
What Prism adds to private payments.
The compliance oracle (in-circuit caps + auditor selective disclosure) is the piece base SPP does not have. Aggregation makes it scale.
Batch aggregation
Settle many private transfers in a single verification; verification cost stays constant as the batch grows.
In-circuit compliance caps
Total and per-transfer limits are hard proof constraints, so a non-compliant batch simply cannot produce a proof.
Auditor selective disclosure
Each amount is encrypted to the auditor's key on-chain; the auditor verifies the total without anyone de-shielding.
One flat verify vs. linear naive verification.
Prism's verification cost is constant in K (one BN254 verify); verifying each transfer separately grows linearly and crosses Stellar's real testnet limit. K=2/4/8 are measured on testnet; K=13 is projected.
measured at K=2/4/8, constant in K
K=2/4/8 measured; sublinear, far under the limit
31.4M per separate verify · projected, linear in K
The structural win is ceiling-independent: one flat verify can attest a batch of any size, while naive verification is strictly linear. Constraints 101,842/201,096/399,604 at K=2/4/8 (ptau 2^17/2^18/2^19).
Compliant, confidential settlement at institutional scale.
Tokenized fund shares
Settle investor allocations privately while proving caps and totals to the fund administrator.
Confidential payroll & treasury
Batch salary or treasury transfers with amounts hidden, yet compliance provable to finance and audit.
Private stablecoin settlement
Institutions settle large volumes with counterparties hidden and totals auditable by regulators.
RWA settlement with auditor oversight
Regulated real-world-asset transfers stay private on-chain, verifiable on demand by a mandated auditor.
Real SPP transfers, settled on testnet.
Per-K fresh stacks. Every aggregated settlement is a real on-chain transaction; open them on the explorer.
- · Real: on-chain verify, all-or-nothing nullifier spend, compliance caps, auditor decryption, with real SPP
policy_tx_2_2witnesses. - · Aggregation-by-batching, not recursion: one proof re-proves K real transfers; it does not recursively verify K proofs.
- · In the live demo the proof is pre-generated (proving K transfers takes minutes) while the settlement transaction is live.
- · The relayer / EVM-omnichain lane is secondary and runs in attestation mode; BLS12-381 dual-curve is roadmap.
From testnet to a mainnet issuer pilot.
See it settle live on Stellar testnet.
A 2-3 minute guided flow: a real aggregated settlement, the compliance caps, and the auditor decrypting on-chain ciphertexts, with a live transaction you can open on the explorer.