solana-keychain

Flexible, framework-agnostic Solana transaction signing for Rust applications

⚠️ SECURITY NOTICE: This library has not been audited. Use at your own risk. Not recommended for production use with real funds without a thorough security review. The authors and contributors are not responsible for any loss of funds or damages resulting from the use of this library.

solana-keychain provides a unified interface for signing Solana transactions with multiple backend implementations. Whether you need local keypairs for development, enterprise vault integration, or managed wallet services, this library offers a consistent API across all signing methods.

Features

• Unified Interface: Single SolanaSigner trait for all backends
• Async-First: Built with async/await for modern Rust applications
• Modular: Feature flags for zero-cost backend selection
• Type-Safe: Compile-time guarantees and error handling
• Minimal Dependencies: Only include what you use

Supported Backends

Installation

[dependencies]
# Basic usage (memory signer only)
solana-keychain = "0.1"

# With Vault support
solana-keychain = { version = "0.1", features = ["vault"] }

# All backends
solana-keychain = { version = "0.1", features = ["all"] }

Quick Start

Memory Signer (Local Development)

use solana_keychain::{MemorySigner, SolanaSigner};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create signer from private key
    let signer = MemorySigner::from_private_key_string(
        "[41,99,180,88,51,57,48,80,61,63,219,75,176,49,116,254...]"
    )?;

    // Get public key
    let pubkey = signer.pubkey();
    println!("Public key: {}", pubkey);

    // Sign a message
    let message = b"Hello Solana!";
    let signature = signer.sign_message(message).await?;
    println!("Signature: {}", signature);

    Ok(())
}

AWS KMS Signer

use solana_keychain::{KmsSigner, SolanaSigner};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create signer using AWS KMS
    // Credentials are loaded from the AWS default credential chain
    let signer = KmsSigner::new(
        "arn:aws:kms:us-east-1:123456789012:key/12345678-1234-1234-1234-123456789012".to_string(),
        "YourSolanaPublicKeyBase58".to_string(),
        Some("us-east-1".to_string()), // Optional region
    ).await?;

    // Sign a message
    let message = b"Hello Solana!";
    let signature = signer.sign_message(message).await?;
    println!("Signature: {}", signature);

    Ok(())
}

AWS Credentials

The AWS KMS signer uses the AWS default credential provider chain. Credentials are automatically loaded from:

1. Environment variables: AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_SESSION_TOKEN
2. Shared credentials file: ~/.aws/credentials
3. IAM role (automatic on EC2, ECS, Lambda)
4. Web identity token (for EKS/Kubernetes with IRSA)

Creating an AWS KMS Key

aws kms create-key \
  --key-spec ECC_NIST_EDWARDS25519 \
  --key-usage SIGN_VERIFY \
  --description "Solana signing key"

Required IAM permissions:

{
    "Version": "2012-10-17",
    "Statement": [{
        "Effect": "Allow",
        "Action": ["kms:Sign", "kms:DescribeKey"],
        "Resource": "arn:aws:kms:*:*:key/*"
    }]
}

Core API

All signers implement the SolanaSigner trait:

#[async_trait]
pub trait SolanaSigner: Send + Sync {
    /// Get the public key of this signer
    fn pubkey(&self) -> Pubkey;

    /// Sign a Solana transaction (modifies transaction in place)
    async fn sign_transaction(&self, tx: &mut Transaction) -> Result<Signature, SignerError>;

    /// Sign arbitrary message bytes
    async fn sign_message(&self, message: &[u8]) -> Result<Signature, SignerError>;

    /// Check if the signer is available and healthy
    async fn is_available(&self) -> bool;
}

Contributing

Local Development

Local development and testing use Just as a build and development tool--make sure to install it before running any commands.

just build
just test
just fmt

Adding a New Signer Backend

Interested in adding a new signer backend? Check out our guide for adding new signers.