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How Privora Works

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System Components

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Sequencer

• Receives encrypted data submissions from clients
• Manages the content-addressable data store
• Executes FHE operations via the modified Solana runtime
• Batches and settles transactions to Solana L1

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Content-Addressable Store

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FHE Runtime

• Custom syscalls for FHE operations (sol_fhe_add, sol_fhe_mul, etc.)
• Extended heap size (~1MB) for ciphertext processing
• Integration with the TFHE library for actual computations

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Data Flow

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Encryption and Submission

1. Client encrypts a value using the sequencer’s FHE public key
2. Client submits the ciphertext to the sequencer
3. Sequencer computes SHA256 hash of the ciphertext
4. Ciphertext is stored in the content store
5. Hash is returned to the client for use in transactions

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Program Execution

1. Client sends transaction containing hash references to encrypted data
2. Program loads encrypted values using EncryptedRef::load()
3. Runtime fetches ciphertexts from the data store
4. FHE operations are performed on the encrypted data
5. Results are stored back via Encrypted::store()
6. New hash references are saved in program accounts

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Decryption

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Account Layout

/// On-chain account structure
#[derive(BorshSerialize, BorshDeserialize)]
pub struct PrivoraAccount {
    // Regular Solana account fields
    pub owner: Pubkey,              // 32 bytes
    pub status: u8,                 // 1 byte

    // Hash references to encrypted data (NOT the ciphertext!)
    pub encrypted_value: EncryptedRef<u64>,  // 32 bytes (just the hash)
    pub encrypted_flag: EncryptedBoolRef,    // 32 bytes
}

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Security Model

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Trust Assumptions

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Data Privacy

• Encrypted data: Only hash references are on-chain; ciphertexts are off-chain
• Computation privacy: FHE operations never expose plaintext
• Access control: Authorization PDAs control who can request decryption
• User recovery: Optional X25519 encryption for instant local decryption

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Comparison with Other Approaches

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Next Steps