Inco SVM — Confidential Computing on Solana

Inco Lightning is a confidentiality layer for Solana that enables developers to build applications where sensitive data remains encrypted even during computation. It uses Trusted Execution Environments (TEEs) to deliver verifiable confidential compute — no new chain, no new wallet required.

Note: Inco SVM is currently in beta on Solana devnet. Features are subject to change.

Overview

Encrypted Types — Euint128 and Ebool handles representing encrypted values stored off-chain
Homomorphic Operations — Arithmetic, comparison, bitwise, and control flow on encrypted data via CPI
Access Control — Allowance PDA system for granting per-handle decryption permissions
Attested Decryption — Ed25519 signature-verified decryption through TEE covalidators
Confidential SPL Token — Privacy-preserving token standard with encrypted balances and transfers
Client SDK — @inco/solana-sdk for encryption, decryption, and utility helpers

Architecture

Client                    Solana Program              Inco Covalidator (TEE)
  │                            │                              │
  ├─ encryptValue() ──────────►│                              │
  │                            ├─ CPI: new_euint128 ─────────►│
  │                            │◄─── handle (u128) ──────────┤
  │                            ├─ CPI: e_add / e_sub / ... ──►│
  │                            │◄─── result handle ──────────┤
  │                            ├─ CPI: allow() ──────────────►│
  │                            │                              │
  ├─ decrypt([handle]) ───────────────────────────────────────►│
  │◄─── plaintext + Ed25519 attestation ──────────────────────┤

Inco Lightning Program ID: 5sjEbPiqgZrYwR31ahR6Uk9wf5awoX61YGg7jExQSwaj

Quick Start

Installation

Rust Crate (on-chain):

Add to your Cargo.toml:

[dependencies]
inco-lightning = { version = "0.1", features = ["cpi"] }

Add to Anchor.toml:

[programs.devnet]
inco_lightning = "5sjEbPiqgZrYwR31ahR6Uk9wf5awoX61YGg7jExQSwaj"

JavaScript SDK (client-side):

npm install @inco/solana-sdk

Basic Program Setup

use anchor_lang::prelude::*;
use inco_lightning::cpi::accounts::Operation;
use inco_lightning::cpi::{e_add, e_sub, e_ge, e_select, new_euint128, as_euint128};
use inco_lightning::types::{Euint128, Ebool};
use inco_lightning::ID as INCO_LIGHTNING_ID;

declare_id!("YOUR_PROGRAM_ID");

#[program]
pub mod my_confidential_program {
    use super::*;

    pub fn deposit(ctx: Context<Deposit>, ciphertext: Vec<u8>) -> Result<()> {
        let cpi_ctx = CpiContext::new(
            ctx.accounts.inco_lightning_program.to_account_info(),
            Operation {
                signer: ctx.accounts.authority.to_account_info(),
            },
        );

        // Create encrypted handle from client ciphertext
        let amount: Euint128 = new_euint128(cpi_ctx.clone(), ciphertext, 0)?;

        // Add to existing balance
        let new_balance = e_add(cpi_ctx, ctx.accounts.vault.balance, amount, 0)?;
        ctx.accounts.vault.balance = new_balance;

        Ok(())
    }
}

#[derive(Accounts)]
pub struct Deposit<'info> {
    #[account(mut)]
    pub authority: Signer<'info>,
    #[account(mut)]
    pub vault: Account<'info, Vault>,
    /// CHECK: Inco Lightning program
    #[account(address = INCO_LIGHTNING_ID)]
    pub inco_lightning_program: AccountInfo<'info>,
}

#[account]
pub struct Vault {
    pub balance: Euint128,
}

Basic Client Usage

import { encryptValue } from "@inco/solana-sdk/encryption";
import { decrypt } from "@inco/solana-sdk/attested-decrypt";

// Encrypt a value before sending to program
const encrypted = await encryptValue(1000n);

await program.methods
  .deposit(Buffer.from(encrypted, "hex"))
  .accounts({ authority: wallet.publicKey, vault: vaultPda, incoLightningProgram: INCO_LIGHTNING_ID })
  .rpc();

// Decrypt a handle (requires wallet signature)
const result = await decrypt([handleString], {
  address: wallet.publicKey,
  signMessage: wallet.signMessage,
});
console.log("Decrypted:", result.plaintexts[0]);

Encrypted Types & Handles

Handles are 128-bit references to encrypted values stored off-chain in the covalidator network.

Type	Description	Rust Definition
`Euint128`	Encrypted unsigned 128-bit integer	`pub struct Euint128(pub u128)`
`Ebool`	Encrypted boolean	`pub struct Ebool(pub u128)`

Store handles directly in account structs:

#[account]
pub struct ConfidentialAccount {
    pub balance: Euint128,
    pub is_active: Ebool,
}

Input Functions

Function	Description
`new_euint128(ctx, ciphertext, input_type)`	Create from client-encrypted ciphertext
`new_ebool(ctx, ciphertext, input_type)`	Create encrypted bool from ciphertext
`as_euint128(ctx, value)`	Trivial encryption of plaintext u128 (for constants like zero)
`as_ebool(ctx, value)`	Trivial encryption of plaintext bool

Operations on Encrypted Data

All operations require a CPI context and return new handles.

let cpi_ctx = CpiContext::new(
    ctx.accounts.inco_lightning_program.to_account_info(),
    Operation { signer: ctx.accounts.authority.to_account_info() },
);
let result = e_add(cpi_ctx, a, b, 0)?;

The last parameter (scalar_byte) is 0 for encrypted-encrypted operations, 1 when the left operand is plaintext.

Arithmetic → `Euint128`

e_add, e_sub, e_mul, e_rem

Comparison → `Ebool`

e_ge, e_gt, e_le, e_lt, e_eq

Bitwise → `Euint128`

e_and, e_or, e_not, e_shl, e_shr

Control Flow (Multiplexer)

// Cannot use if/else on encrypted values — use e_select instead
let result = e_select(cpi_ctx, condition, if_true, if_false, 0)?;

Random Number Generation

let random_value = e_rand(cpi_ctx, 0)?;

See resources/rust-sdk-reference.md for the complete API.

Access Control

Decryption permissions are managed through Allowance PDAs derived from [handle.to_le_bytes(), allowed_address].

use inco_lightning::cpi::accounts::Allow;
use inco_lightning::cpi::allow;

let cpi_ctx = CpiContext::new(
    ctx.accounts.inco_lightning_program.to_account_info(),
    Allow {
        allowance_account: ctx.accounts.allowance_account.to_account_info(),
        signer: ctx.accounts.authority.to_account_info(),
        allowed_address: ctx.accounts.user.to_account_info(),
        system_program: ctx.accounts.system_program.to_account_info(),
    },
);
allow(cpi_ctx, handle.0, true, user_pubkey)?;

Important: Operations produce new handles, and allowance PDAs depend on the handle value. You must simulate the transaction first to get the result handle, derive the PDA, then submit with remaining_accounts.

See resources/access-control.md for the full simulation-then-submit pattern.

Attested Decryption

Two modes:

Mode	Purpose	Returns
Attested Reveal	Display values in UI	`result.plaintexts`
Attested Decrypt	Verify values on-chain	`result.ed25519Instructions` + program IX

import { decrypt } from "@inco/solana-sdk/attested-decrypt";

const result = await decrypt([handle], {
  address: wallet.publicKey,
  signMessage: wallet.signMessage,
});

// Reveal: use plaintext directly
console.log(result.plaintexts[0]);

// Decrypt: verify on-chain
const tx = new Transaction();
result.ed25519Instructions.forEach(ix => tx.add(ix));
tx.add(yourProgramVerifyInstruction);
await sendTransaction(tx);

On-chain verification:

use inco_lightning::cpi::is_validsignature;
use inco_lightning::cpi::accounts::VerifySignature;

let cpi_ctx = CpiContext::new(
    ctx.accounts.inco_lightning_program.to_account_info(),
    VerifySignature {
        instructions: ctx.accounts.instructions.to_account_info(),
        signer: ctx.accounts.authority.to_account_info(),
    },
);
is_validsignature(cpi_ctx, 1, Some(handles), Some(plaintext_values))?;

Confidential SPL Token

A full privacy-preserving token implementation. See resources/confidential-spl-token.md.

Key functions: initialize_mint, create_account, mint_to, transfer, approve

// Encrypt and transfer
const encrypted = await encryptValue(500_000_000n);
await program.methods
  .transfer(Buffer.from(encrypted, "hex"), 0)
  .accounts({ source: srcAta, destination: destAta, authority: wallet.publicKey })
  .rpc();

Best Practices

Always call allow() after operations that produce handles you want to decrypt later
Use remaining_accounts to pass allowance PDAs and grant access in the same transaction
Grant minimal permissions — only allow specific addresses to decrypt what they need
Use the multiplexer pattern (e_select) instead of if/else on encrypted conditions
Trivial encryption only for constants (like zero) — use client-side encryption for sensitive values
Verify the intended handle in attestations to prevent handle-swap attacks
Simulate transactions first to get result handles before deriving allowance PDAs

Resources

Skill Structure

inco/
├── SKILL.md                              # This file — main reference
├── docs/
│   └── troubleshooting.md                # Common issues and solutions
├── examples/
│   ├── basic-operations/
│   │   └── encrypted-operations.ts       # Arithmetic, comparison, select
│   ├── confidential-spl-token/
│   │   ├── mint-and-transfer.ts          # Mint & transfer confidential tokens
│   │   └── reveal-balance.ts             # Decrypt and reveal token balance
│   └── private-raffle/
│       └── raffle-client.ts              # Full raffle lifecycle client
├── resources/
│   ├── rust-sdk-reference.md             # Complete Rust CPI API
│   ├── js-sdk-reference.md               # JS SDK encryption & decryption
│   ├── access-control.md                 # Allowance PDAs & simulation pattern
│   └── confidential-spl-token.md         # SPL token program reference
└── templates/
    └── inco-svm-setup.ts                 # Starter template with helpers

inco-svm