Privacy Technology

Explore the cryptographic techniques that power NINJA's confidential transfers and privacy features.

Technical Overview

NINJA leverages Solana's Confidential Transfer Extension, which is part of the Token-2022 standard. This extension enables private token transfers by utilizing advanced cryptography and zero-knowledge proofs. Here's how it works at a high level:

Encrypted balances: User balances are encrypted using ElGamal encryption, making them unreadable to outside observers
Zero-knowledge proofs: When sending tokens, the sender generates cryptographic proofs that validate the transfer without revealing the amount
On-chain verification: The Solana network verifies these proofs to ensure transfers are valid without learning the actual amounts
Recipient decryption: Only the recipient, with their private keys, can decrypt and view the transferred amount

These cryptographic systems work together to create a secure, verifiable, and private token transfer system on Solana.

Key Technologies

ElGamal Encryption

ElGamal encryption is a public-key cryptosystem used to encrypt token balances on the blockchain. It has the unique property of being additively homomorphic, which means mathematical operations can be performed on encrypted values without decrypting them.

In NINJA, ElGamal encryption protects the confidentiality of token balances while still allowing the verification of transactions. When you deposit tokens into your confidential account, your balance is encrypted and stored on-chain in this format.

Zero-Knowledge Proofs

Zero-knowledge proofs (ZKPs) are cryptographic methods that allow one party to prove to another that a statement is true without revealing any additional information beyond the validity of the statement itself.

NINJA uses ZKPs to:

Prove that the sender has sufficient funds for a transfer without revealing their actual balance
Verify that the amount being transferred is valid (non-negative and within range constraints)
Ensure that the computation of new encrypted balances is correct

The specific ZKP implementation used in Solana's confidential transfers is a variant of Bulletproofs, which are efficiently verifiable and don't require a trusted setup.

Pedersen Commitments

Pedersen commitments are cryptographic primitives that allow you to commit to a value while keeping it hidden, with the ability to reveal it later. They have two key properties:

Hiding: The commitment does not reveal the committed value
Binding: The committed value cannot be changed once committed

In NINJA, Pedersen commitments are used as part of the ZKP system to create secure and verifiable representations of transaction amounts without revealing the actual values.

Auditable Encryption

The Solana Confidential Transfer Extension includes optional auditor functionality. This feature allows designated entities (auditors) to decrypt and view encrypted balances and transfer amounts, which can be useful for regulatory compliance.

Key aspects of the auditor system:

Account holders can choose to enable or disable auditor access
Multiple auditors can be supported at the token mint level
Encrypted transfer amounts include additional encryption specifically for auditors

NINJA implementation allows for this functionality but makes it optional, putting privacy control in the hands of users.

Ninja Mode Technology

Ninja Mode enhances privacy by adding path obfuscation on top of confidential transfers. This is achieved through a combination of techniques:

Multi-hop routing: Transactions are routed through intermediate relay services that break the chain of direct connection
Delayed execution pools: Transactions can be pooled with others and executed in batches, making correlation more difficult
Transaction mixing: Multiple transfers are combined in ways that obscure the direct path between senders and recipients

Privacy Considerations

Even with path obfuscation, sophisticated statistical analysis of blockchain data might still potentially identify patterns that could link some transactions. Ninja Mode significantly increases privacy but does not guarantee absolute unlinkability against advanced analysis.

The path obfuscation in Ninja Mode operates on the application layer rather than the protocol layer, allowing it to leverage Solana's underlying confidential transfer capabilities while adding additional privacy features.