Payment Instructions

Every transaction on Silo generates a Payment Instruction. This is an encrypted record that contains the complete details of the transaction and serves as Silo’s internal audit trail. Payment Instructions distinguish Silo from pure privacy protocols. Privacy tools like Tornado Cash and Railgun provide on-chain unlinkability but maintain no record of who paid who. If a dispute arises or a regulator requests information, there is nothing to reference. Silo provides the same on-chain unlinkability while maintaining a structured, encrypted record behind every transaction that can support disputes, audits, and regulatory compliance.

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What a Payment Instruction Contains

Each Payment Instruction records the full context of a transaction: sender identity, receiver identity, the amount sent, the amount received, the asset and chain used by the sender, the asset and chain delivered to the receiver, all wallet addresses involved, routing details (swap paths, bridge used), ZK proof references, compliance check results, and timestamps for each stage of the transaction. This is the complete record of the transaction.

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How Payment Instructions Are Stored

Payment Instructions are built incrementally throughout the payment lifecycle. As each step of the transaction is processed (deposit, routing, compliance checks, withdrawal), the relevant data is captured and stored securely in Silo’s internal database. Once the receiver has completed their withdrawal, the full Payment Instruction is finalized, encrypted using SEAL, and uploaded to Walrus (Sui’s decentralized storage layer) via a background process. SEAL handles the encryption, ensuring the contents are not readable without authorized access. Walrus provides durable, decentralized storage so that records are not dependent on a single server or database. The combination means that Payment Instructions are tamper-resistant, durable, and encrypted at rest. They cannot be read by public blockchain observers, by other Silo users, or by anyone without authorized access through Silo’s backend.

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Who Can Access Payment Instructions

Payment Instructions are accessible only to Silo’s backend under defined access controls. Users do not see Payment Instructions directly. Instead, they receive redacted receipts (see Redacted Receipts) that contain a subset of the transaction details appropriate for each party. Access to the full Payment Instruction is reserved for specific operational needs: dispute resolution between parties, regulatory or audit requests under applicable legal processes, and internal compliance review. The access control framework is designed to balance two requirements. Users need privacy from the public and from each other. Regulators and auditors need the ability to verify that transactions are legitimate and compliant. Payment Instructions satisfy both by keeping the full record encrypted and access-controlled while giving users redacted, non-doxxing receipts.

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Why This Matters

The Payment Instruction system is what allows Silo to offer privacy and compliance simultaneously without treating them as a tradeoff. The on-chain layer provides unlinkability. The Payment Instruction layer provides accountability. Users get private transactions. Regulators get an auditable trail. Neither side has to compromise. This architecture is also what separates Silo from custodial platforms. Custodial apps like Venmo and PayPal maintain internal transaction records, but those records exist because the platform controls the funds. Silo maintains encrypted records without taking custody. The audit trail exists independently of fund control.