# SeedPGP v1.1.0

**Secure BIP39 mnemonic backup using PGP encryption and QR codes**

A TypeScript/Bun tool for encrypting cryptocurrency seed phrases with OpenPGP and encoding them as QR-friendly Base45 frames with CRC16 integrity checking.

## Features

- 🔐 **PGP Encryption**: Uses cv25519 (Curve25519) for modern elliptic curve cryptography
- 📱 **QR Code Ready**: Base45 encoding optimized for QR code generation
- ✅ **Integrity Checking**: CRC16-CCITT-FALSE checksums prevent corruption
- 🔑 **BIP39 Support**: Full support for 12/18/24-word mnemonics with passphrase indicator
- 🧪 **Battle-Tested**: Validated against official Trezor BIP39 test vectors
- ⚡ **Fast**: Built with Bun runtime for optimal performance

## Installation

```bash
# Clone repository
git clone https://github.com/kccleoc/seedpgp-web.git
cd seedpgp-web

# Install dependencies
bun install

# Run tests
bun test

# Start development server
bun run dev
```

## Usage

### Encrypt a Mnemonic

```typescript
import { encryptToSeedPgp, buildPlaintext } from "./lib/seedpgp";

const mnemonic = "legal winner thank year wave sausage worth useful legal winner thank yellow";
const plaintext = buildPlaintext(mnemonic, false); // false = no BIP39 passphrase used

const result = await encryptToSeedPgp({
  plaintext,
  publicKeyArmored: yourPgpPublicKey,
});

console.log(result.framed); // SEEDPGP1:0:ABCD:BASE45DATA...
console.log(result.recipientFingerprint); // Key fingerprint for verification
```

### Decrypt a SeedPGP Frame

```typescript
import { decryptSeedPgp } from "./lib/seedpgp";

const decrypted = await decryptSeedPgp({
  frameText: "SEEDPGP1:0:ABCD:BASE45DATA...",
  privateKeyArmored: yourPrivateKey,
  privateKeyPassphrase: "your-key-password",
});

console.log(decrypted.w); // Recovered mnemonic
console.log(decrypted.pp); // BIP39 passphrase indicator (0 or 1)
```

## Frame Format

```
SEEDPGP1:FRAME:CRC16:BASE45DATA

SEEDPGP1 - Protocol identifier and version
0        - Frame number (0 = single frame)
ABCD     - 4-digit hex CRC16-CCITT-FALSE checksum
BASE45   - Base45-encoded PGP message
```

## API Reference

### `buildPlaintext(mnemonic, bip39PassphraseUsed, recipientFingerprints?)`

Creates a SeedPGP plaintext object.

**Parameters:**

- `mnemonic` (string): BIP39 mnemonic phrase (12/18/24 words)
- `bip39PassphraseUsed` (boolean): Whether a BIP39 passphrase was used
- `recipientFingerprints` (string[]): Optional array of recipient key fingerprints

**Returns:** `SeedPgpPlaintext` object

### `encryptToSeedPgp(params)`

Encrypts a plaintext object to SeedPGP format.

**Parameters:**

```typescript
{
  plaintext: SeedPgpPlaintext;
  publicKeyArmored?: string;      // PGP public key (PKESK)
  messagePassword?: string;        // Symmetric password (SKESK)
}
```

**Returns:**

```typescript
{
  framed: string;                  // SEEDPGP1 frame
  pgpBytes: Uint8Array;            // Raw PGP message
  recipientFingerprint?: string;   // Key fingerprint
}
```

### `decryptSeedPgp(params)`

Decrypts a SeedPGP frame.

**Parameters:**

```typescript
{
  frameText: string;                // SEEDPGP1 frame
  privateKeyArmored?: string;       // PGP private key
  privateKeyPassphrase?: string;    // Key unlock password
  messagePassword?: string;         // SKESK password
}
```

**Returns:** `SeedPgpPlaintext` object

## Testing

```bash
# Run all tests
bun test

# Run with verbose output
bun test --verbose

# Watch mode (auto-rerun on changes)
bun test --watch
```

### Test Coverage

- ✅ 15 comprehensive tests
- ✅ 8 official Trezor BIP39 test vectors
- ✅ Edge cases (wrong key, wrong passphrase)
- ✅ Frame format validation
- ✅ CRC16 integrity checking

## Security Considerations

### ✅ Best Practices

- Uses **AES-256** for symmetric encryption
- **cv25519** provides ~128-bit security level
- **CRC16** detects QR scan errors (not cryptographic)
- Key fingerprint validation prevents wrong-key usage

### ⚠️ Important Notes

- **Never share your private key or encrypted QR codes publicly**
- Store backup QR codes in secure physical locations (safe, safety deposit box)
- Use a strong PGP key passphrase (20+ characters)
- Test decryption immediately after generating backups
- Consider password-only (SKESK) encryption as additional fallback

## Project Structure

```
seedpgp-web/
├── src/
│   ├── lib/
│   │   ├── seedpgp.ts        # Core encryption/decryption
│   │   ├── seedpgp.test.ts   # Test vectors
│   │   ├── base45.ts         # Base45 codec
│   │   ├── crc16.ts          # CRC16-CCITT-FALSE
│   │   └── types.ts          # TypeScript definitions
│   └── App.tsx               # React UI
├── package.json
└── README.md
```

## Tech Stack

- **Runtime**: [Bun](https://bun.sh) v1.3.6+
- **Language**: TypeScript
- **Crypto**: [OpenPGP.js](https://openpgpjs.org) v6.3.0
- **Framework**: React + Vite
- **Testing**: Bun test runner

## Roadmap

- [ ] QR code generation UI
- [ ] Multi-frame support for larger payloads
- [ ] Hardware wallet integration
- [ ] Mobile scanning app
- [ ] Shamir Secret Sharing support

## License

MIT License - see LICENSE file for details

## Author

**kccleoc** - [GitHub](https://github.com/kccleoc)

## Version History

### v1.1.0 (2026-01-28)

- Initial public release
- Full BIP39 mnemonic support
- Trezor test vector validation
- Production-ready implementation

---

⚠️ **Disclaimer**: This software is provided as-is. Always test thoroughly before trusting with real funds. The author is not responsible for lost funds due to software bugs or user error.

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