Confidential SPL Token merges SPL Token, Token-2022, the Confidential Transfer Extension, and Arcium’s encrypted MPC-powered computing into one seamless aggregate standard. It solves the limitations that have hindered privacy adoption on Solana and unlocks a new generation of confidential DeFi, payments, and stablecoin applications on Solana.

The standard is currently in active development following conversations with core engineers, developers, institutional players, and infrastructure teams who all shared the same message: confidentiality is critical, but current solutions are too difficult to implement or offer limited usability. We’re actively working with ecosystem partners to bring it live — with early access to selected teams to be announced soon.

Why Confidential SPL Token? 

Confidentiality is one of the most basic forms of privacy. In the context of public blockchains, it means encrypting token amounts, balances, and other metadata. This has been a fundamental missing piece for adoption, either absent altogether or too complex to integrate, often relying on solutions that feel bolted on. The Confidential SPL Token standard changes that, bringing the familiar SPL experience to developers with confidentiality built in.

Despite the launch of Token-2022 and the Confidential Transfer Extension, adoption has been quite limited, which we believe is in small part due to difficult DevEx and in large part due to it not being usable directly by on-chain programs in a confidential way. We propose the Confidential SPL Token Standard to resolve these issues. With Confidential SPL Tokens teams can finally add confidentiality to any Solana program and applications. Payments, stablecoins, trading, lending – all can now preserve privacy by default. Teams can further build entire confidential applications with their public program on Solana, all powered by Arcium's encrypted computing.

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Key features of the Confidential SPL token standard include:

• Full interoperability with SPL Token, Token-2022, and Confidential Transfer Extension.
• Fixes critical limitations of Token-2022’s Confidential Transfer model (e.g., adding support for program/PDA owned token accounts enabling use in DeFi, recipient account creation, etc.).
• Confidential control and transfers directly within any on-chain program.
• Confidential usage of any existing SPL token.
• Confidential DeFi, stablecoins, and payments are now finally possible on Solana with these improvements.

Understanding Confidential SPL Token

The Confidential SPL Token Standard is solving the problems developers faced with Token2022, while simplifying the whole interface.

‍1. On-Chain Programmatic Access to Confidential Transfers

Token-2022's Confidential Transfers only allow EOAs (Externally Owned Accounts) to control confidential token accounts. This prevents any smart contract on Solana from interacting with confidential balances, effectively disabling confidential DeFi.

Confidential SPL Token solves this by leveraging Arcium's private state management and compute: Programs can manage confidential token accounts and perform confidential transfers using Arcium, unlocking private DeFi and programmable privacy.

2. Ability to Create Token Accounts for Others

Token-2022 requires recipients to pre-create confidential token accounts. This breaks basic UX expectations – senders can’t initiate a confidential transfer unless the recipient has already set up an account (for each token) which is a flaw that introduces an incredible level of friction.

With Confidential SPL Token, senders can create confidential token accounts on behalf of recipients, just like standard SPL transfers – no pre-setup required. This works by leveraging Arcium to create temporary confidential token accounts owned and only decryptable by the Confidential ATA program. The recipient can then later claim the confidential token account and take ownership of it, along with providing their decryption key, to which the confidential token account is then encrypted to.

3. Canonical Confidential Mints

Developers and users rely on standard SPL tokens. However, bridging to confidential assets has required new manual mints, wrappers, or reliance on original token issuers.

Confidential SPL Token enables canonical confidential wrapped mints, allowing any SPL token to be wrapped into a unified, confidential variant without the user even noticing by leveraging the token-wrap program. An arbitrary number of wrapped tokens can be automatically interpreted as the canonical SPL token. A new feature also allows the original mint authority to be set as auditor (without requiring any action on their part).

4. Simplified Developer Experience

Integrating confidential transfers has been overly complex. Developers need a familiar, straightforward interface.

Confidential SPL Token mimics the SPL token experience by abstracting away the complexity of different token protocols and providing a unified interface, making confidential transfers as easy to use as public ones.

Protocol Architecture

The Confidential SPL Token standard is designed as a unified abstraction layer over multiple token protocols on Solana, enabling seamless interoperability between public and confidential token operations while removing prior complexities and introducing powerful new features.

Confidential SPL Token achieves its functionality through the aggregation and combination of multiple programs and protocols:

Existing Programs and Protocols:

• SPL Token Program for SPL token mints, deposits, and withdrawals of public tokens.
• Token-2022 with Confidential Transfer Extension for confidential mints and basic EOA-based confidential transfers.
• Token Wrap Program to enable wrapping any SPL Token into a Confidential SPL Token (1 SPL Token Mint ↦ n Token-2022 Mints).

New Programs and Protocols:

• Confidential Transfer Adapter – brings non-EOA (on-chain program) support to the Token-2022 Confidential Transfer Extension using Arcium.
  
  • Token-2022 with the Confidential Transfer Extension only supports EOA-controlled confidential balances and transfers.
  • The program owns the confidential balances, yet nobody can see into these balances (unless the program explicitly allows it).
  • The Confidential Transfer Adapter enables direct confidential transfers and token control within Solana programs without any trusted intermediary.
  • Encrypted SPL Token connects directly to this adapter as an additional abstraction, enabling faster, larger, and cheaper transfers and DeFi operations.

• Confidential Auditor Adapter – adds programmable and privacy-preserving compliance.
  
  • This adapter extends the current auditing capabilities to support more flexible and private compliance systems.
  • Crucially, it allows auditors to be specified without requiring knowledge of the auditor’s decryption public key (which is a requirement in Token-2022).

• Encrypted SPL Token – a new Arcium-powered confidential token standard tailored for non-EOAs (on-chain programs).
  
  • This token program features lighter-weight accounts and operations than Token-2022’s Confidential Transfer Extension.
  • A revised ciphertext scheme supports direct encrypted execution in Arcium’s Cerberus MPC.

• Confidential ATA Program – allows confidential token accounts to be created for any third-party owner without requiring action on their end.
  
  

The same SPL experience, now encrypted

Tokens without privacy aren't good enough for institutions. TradFi has long offered stronger privacy than public blockchains. In order to bring institutions on chain, privacy is a prerequisite needed to protect secrets, clients, strategy, and treasury operations. Confidential SPL Token simply extends the foundational SPL standard on Solana, unifying the developer experience to enable confidentiality. With these issues solved, developers and institutions can can now tap into one unified, familiar standard to enable the privacy everyone expects.

Confidential SPL Token is currently under active development. We are welcoming teams looking to implement confidentiality or have experienced previous pain points in doing so to reach out us! Feel free to send us a DM on X or join our Discord and open a support ticket.