RADR is a project that aims to provide a native private payment infrastructure on the Solana blockchain. It utilizes zero-knowledge proof technology to enable confidential transactions for merchants, developers, and individual users. ^[1]

Overview

RADR is a privacy-focused financial infrastructure designed to advance financial privacy and freedom on the Solana network. The project operates on the principle that financial privacy is a fundamental right and presents itself as an open-source, community-driven initiative that is not directed by venture capital investors. The core technology is engineered to obscure transaction details, such as payment amounts and sender identities, making them unreadable to third parties, including network validators and public block explorers. The infrastructure is live on the Solana mainnet and has undergone an independent security audit. ^[1]

The system's primary goal is to break the on-chain link between a payer's wallet and a merchant's or recipient's wallet. To achieve this, it employs a relayer-mediated settlement system combined with an escrow-based model. Users deposit funds into Program Derived Addresses (PDAs), and a relayer executes verified payments from these accounts. This architecture is intended to provide a "gasless" experience for the end-user, as the relayer covers the Solana network transaction fees. The protocol is also designed to implement the x402 "Payment Required" HTTP standard, facilitating machine-to-machine payments for applications such as API monetization and services for autonomous AI agents. ^[2]

Products

RADR is developing a suite of privacy-first decentralized finance (DeFi) protocols and tools. The product line includes both live applications and planned future developments.

• ShadowPay: The flagship product, ShadowPay is a private payment protocol live on the Solana mainnet. It enables confidential transactions, subscriptions, and usage-based billing by implementing the x402 standard. It serves as the core infrastructure for the project's other offerings. ^[2]
• ShadowPay SDK: A software development kit for developers to integrate private payment functionalities into their applications on Solana. A key component is the @shadowpay/core library, an open-source package that provides the cryptographic foundation, including functions for encryption, hashing, and generating commitments. ^[3]
• Shopify App: An e-commerce integration that allows merchants on the Shopify platform to accept private payments. This app enables customers to complete purchases with sender anonymity, hiding the direct link between their wallet and the transaction. ^[2]
• ShadowID: A planned decentralized identity system based on Merkle trees. It is designed to work in conjunction with ShadowPay to provide users with an anonymous identity layer for private interactions. ^[1]
• Service Marketplace: A registry for discovering and interacting with x402-compliant APIs and services. This platform is intended to facilitate a machine-to-machine economy where services can be paid for privately. ^[2]
• Agent Registry: A planned marketplace for registering, discovering, and hiring AI agents that can utilize the ShadowPay protocol for autonomous spending within pre-authorized limits. ^[2]
• ShadowMsg: A future product intended for sending encrypted messages on the Solana network. ^[1]
• ShadowSwap: A future product that will allow for private token swaps, extending privacy features to decentralized trading. ^[1]

Features

The RADR protocol, primarily through its ShadowPay product, incorporates several features designed to ensure privacy, efficiency, and developer accessibility.

• Sender Anonymity and Transaction Privacy: The protocol uses Groth16 ZK-SNARKs (Zero-Knowledge Succinct Non-Interactive Argument of Knowledge) and a relayer settlement model to obscure the payer's on-chain identity. This process breaks the direct link between the sender's and receiver's wallets on the public ledger. ^[2]
• Amount Encryption: Payment amounts are encrypted on-chain using ElGamal encryption on the BN254 elliptic curve. This ensures that while a transaction is publicly recorded, the value transferred remains confidential. ^{[1] [3]}
• On-Chain Verification: The validity of each private payment is confirmed through cryptographic proofs that are verified by Solana validators. This allows the network to validate transactions without needing access to the sensitive underlying data. ^[2]
• x402 Protocol Implementation: The system is built to support the HTTP 402 "Payment Required" standard, which facilitates automated and machine-to-machine payments. This feature is central to use cases involving API monetization and AI agents. ^[1]
• Instant Authorization: The x402 protocol implementation enables fast payment authorization, reported to be under 200 milliseconds. This is achieved by performing ZK verification off-chain before the final settlement occurs via an on-chain escrow. ^[1]
• Multi-Token Support: The protocol is designed to handle payments in Solana's native token (SOL) as well as other SPL tokens, including stablecoins like USDC and USDT. ^{[2] [3]}
• Automated and Recurring Payments: The architecture supports subscriptions and usage-based billing models, making it suitable for Software-as-a-Service (SaaS) platforms, content providers, and other services that require recurring payments. ^[2]
• Spending Authorizations: Users can pre-authorize AI agents or other services to spend funds from their escrow accounts within specified limits, enabling autonomous economic activity. ^[2]
• Developer and Merchant Tools: RADR provides an NPM SDK with TypeScript support for straightforward integration. It also offers webhooks for real-time payment notifications and a merchant dashboard for tracking revenue and managing payouts, which includes privacy-preserving analytics. ^{[1] [2]}

Ecosystem

The RADR ecosystem is a suite of privacy-centric protocols built on the Solana blockchain, designed to provide a comprehensive environment for confidential financial activities. The ecosystem is centered around the ShadowPay protocol, which acts as the foundational layer for private payments. The project is primarily developer-focused, providing the ShadowPay SDK to enable the creation of third-party applications with built-in privacy features. ^[3]

The long-term vision for the ecosystem is to create an integrated suite where users can transact (ShadowPay), manage their digital identity (ShadowID), communicate (ShadowMsg), and trade assets (ShadowSwap) with a high degree of confidentiality. This suite aims to address multiple facets of digital interaction beyond simple payments. The ecosystem is designed to be compatible with major tokens in the Solana ecosystem, including SOL, USDC, and USDT, facilitating its adoption within existing DeFi and Web3 applications. The inclusion of tools like the Shopify app, Service Marketplace, and Agent Registry indicates a strategy to build both consumer-facing and machine-to-machine economies on its privacy infrastructure. ^{[1] [2]}

Use Cases

The platform is designed for a variety of applications where financial privacy is a key requirement.

• Anonymous E-Commerce: To facilitate private online shopping through integrations like the Shopify app, which hides the customer's on-chain identity during checkout.
• AI Agent Payments: To enable autonomous agents to pay for API calls, data, or other digital services without revealing their owner's wallet identity.
• Private Subscriptions: To allow users to subscribe to services with recurring payments that do not create a direct, publicly traceable link to their primary wallet.
• API Monetization and Usage-Based Billing: To support pay-per-request models for APIs and other digital services where both providers and consumers may require privacy.
• Confidential Peer-to-Peer Payments: To allow individuals to send and receive funds where the transaction amount and sender-receiver link are shielded from public view.
• Content Paywalls: To enable creators and publishers to charge for content without exposing the payment history of their audience.
• Shielding On-Chain Activity: To provide a general-purpose tool for users to shield their financial activities from analysis on public blockchain explorers.

These use cases are supported by the protocol's combination of zero-knowledge proofs, encryption, and a relayer-based architecture. ^{[1] [2] [3]}

Architecture

RADR's technical architecture is built on the Solana blockchain and incorporates several cryptographic technologies to ensure privacy and speed. The system's design revolves around unlinking the sender from the receiver through a multi-step, relayer-mediated process.

The core cryptographic primitives include ElGamal encryption on the BN254 elliptic curve for securing transaction amounts and the Poseidon hash function, which is optimized for zero-knowledge proof systems. Poseidon is used to generate cryptographic commitments and nullifiers. Commitments serve as on-chain representations of a transaction that do not reveal the underlying data, while nullifiers are used to prevent the double-spending of a private asset. The system's ZK circuits, which are used to validate transactions privately, are provided as WASM, zkey, and verification key files for developers. ^{[1] [3]}

The transaction flow for a private payment using the ShadowPay protocol follows these steps:

1. Deposit: A user first deposits funds (e.g., SOL or USDC) into a shared Privacy Pool.
2. Funding: An individual escrow account, which is a Program Derived Address (PDA), is automatically funded from the Privacy Pool. This step is designed to be unlinkable to the user's initial deposit.
3. Proof Generation: To make a payment, the user generates a Groth16 ZK proof off-chain. This proof cryptographically attests to the validity of the payment authorization without revealing the user's identity or the transaction details.
4. Submission: The generated proof is submitted to a settler service, which is an off-chain component of the infrastructure.
5. Settlement: A relayer receives the proof from the settler, verifies it on-chain, and upon successful verification, executes the transaction. The relayer withdraws the specified funds from the user's escrow PDA and transfers them to the merchant's wallet. The relayer pays the associated Solana network fees, abstracting this cost from the user.

This architecture ensures that the only on-chain interaction visible is the relayer moving funds from an escrow account to the merchant, effectively breaking the public link to the original depositor. ^[2]

Tokenomics

Detailed information regarding a native token for the RADR project is not available in the provided public documentation. While some documentation mentions "RADR" as a supported SPL token for payments alongside SOL and USDC, specifics about its role, distribution, and governance have not been specified. ^[2]

Allocation

• Information regarding the allocation and distribution schedule of a native RADR token is not publicly available. ^{[1] [2] [3]}

Utilities

• The specific on-chain utilities of a native RADR token, such as its use for staking, fee reductions, or other protocol functions, have not been specified. ^{[1] [2] [3]}

Governance

• Details concerning the governance model for the RADR protocol and the potential role of a native token in decision-making processes have not been disclosed. ^{[1] [2] [3]}

Confirmed Partnerships

The project has established integrations to expand the use of its private payment technology.

• Shopify: RADR has developed a Shopify App to integrate its ShadowPay protocol directly into the e-commerce platform. This partnership enables merchants using Shopify to offer a private checkout option to their customers, allowing for payments with sender anonymity.

This integration represents a key use case for the protocol in the e-commerce sector. ^[2]