Cryptography Skill

Sorcha.Cryptography provides multi-algorithm support (ED25519, P-256, RSA-4096), symmetric encryption (AES, ChaCha20), and BIP39/44 HD wallet derivation. All operations return CryptoResult<T> for explicit error handling—no exceptions for crypto failures.

Quick Start

Key Generation

// Inject ICryptoModule
var keySetResult = await _cryptoModule.GenerateKeySetAsync(WalletNetworks.ED25519);
if (!keySetResult.IsSuccess)
    throw new InvalidOperationException($"Key generation failed: {keySetResult.Status}");

var keySet = keySetResult.Value!;
// keySet.PrivateKey.Key = 64 bytes (ED25519)
// keySet.PublicKey.Key = 32 bytes (ED25519)

Signing & Verification

// Hash then sign
byte[] hash = SHA256.HashData(transactionData);
var signResult = await _cryptoModule.SignAsync(
    hash,
    (byte)WalletNetworks.ED25519,
    keySet.PrivateKey.Key!);

// Verify
var status = await _cryptoModule.VerifyAsync(
    signResult.Value!,
    hash,
    (byte)WalletNetworks.ED25519,
    keySet.PublicKey.Key!);
bool isValid = status == CryptoStatus.Success;

HD Wallet Creation

var keyRing = await _keyManager.CreateMasterKeyRingAsync(WalletNetworks.ED25519, password: null);
// keyRing.Mnemonic = "word1 word2 ... word12" — user must backup
// keyRing.MasterKeySet contains derived keys

Key Concepts

Concept	Usage	Example
WalletNetworks	Algorithm selection	ED25519, NISTP256, RSA4096
CryptoResult<T>	Error handling	.IsSuccess, .Status, .Value
KeySet	Public/private pair	.PrivateKey.Key, .PublicKey.Key
KeyRing	Full wallet with mnemonic	.Mnemonic, .MasterKeySet
.Zeroize()	Secure memory clearing	Call when done with keys

Common Patterns

Platform-Specific Key Storage

// Encryption provider abstraction handles platform differences
var encrypted = await _encryptionProvider.EncryptAsync(privateKey, "wallet-key-id");
// Windows: DPAPI, Linux: Secret Service, Dev: AES-GCM

Address Generation

var address = _walletUtilities.PublicKeyToWallet(publicKey, (byte)WalletNetworks.ED25519);
// Returns: "ws1q8tuvvdykly8n0fy5jkuu8cjw0fu0p6jl5rp9g..."

See Also

• patterns - Algorithm selection, signing workflows, key management
• workflows - Wallet creation, transaction signing, encryption

Related Skills

• See the nbitcoin skill for HD wallet derivation paths (BIP32/39/44)
• See the postgresql skill for encrypted key storage patterns
• See the xunit and fluent-assertions skills for testing crypto code

Documentation Resources

Fetch latest cryptography documentation with Context7.

How to use Context7:

1. Use mcp__context7__resolve-library-id to search for "libsodium" or "System.Security.Cryptography"
2. Query with mcp__context7__query-docs using the resolved library ID

Recommended Queries:

• "ED25519 signing verification"
• "AES-GCM authenticated encryption"
• "BIP39 mnemonic seed derivation"