Finecam | Registration Code

// e) Check expiration / feature flags if (payload.IsExpired) return RegistrationResult.Expired; if (!IsFeatureAllowed(payload)) return RegistrationResult.NotAuthorized;

// c) Cryptographic verification if (!VerifySignature(cleaned)) return RegistrationResult.InvalidSignature;

// 3. Secure persistence ------------------------------------------------------ private void SaveLicenseSecurely(LicensePayload payload)

// Windows: DPAPI ProtectData (CurrentUser) // macOS: Keychain // Linux: libsecret or encrypted file with file‑system ACLs finecam registration code

return RegistrationResult.Success;

private LicensePayload DecodeLicense(string key)

// 1. Public API -------------------------------------------------------------- public RegistrationResult Register(string userInput) // e) Check expiration / feature flags if (payload

// d) Decode license payload (might be base64+AES) LicensePayload payload = DecodeLicense(cleaned); if (payload == null) return RegistrationResult.CorruptPayload;

// a) Sanitize input string cleaned = SanitizeKey(userInput); if (cleaned == null) return RegistrationResult.InvalidFormat;

// 2. Helper functions -------------------------------------------------------- private string SanitizeKey(string input) if (cleaned == null) return RegistrationResult.InvalidFormat

// Typically: key = <payload>.<signature> // Decrypt payload (AES‑GCM) using a per‑install random key that is wrapped // with the public key. Return a typed object.

// 1) Decode base64 segment that contains the digital signature // 2) Use the embedded public key (RSA 2048 or ECDSA P‑256) to verify // 3) Constant‑time comparison to avoid timing attacks