✍️ What is Data Signing?

Data signing is a cryptographic process that ensures a piece of data (e.g., a transaction or message) is securely associated with the authenticated user. It guarantees:

• Authenticity – the user authorized the action.
• Integrity – the data was not tampered with.

REL-ID SDK provides this feature using secure local authentication (biometric/PIN/password) before signing sensitive payloads.

⚙️ How Does It Work?

1. The mobile app initiates a signing request using the authenticateUserAndSignData() API.
2. SDK prompts the user for authentication based on parameters like authLevel and authenticatorType.
3. Upon successful authentication, the SDK signs the payload.
4. SDK emits the event onAuthenticateUserAndSignData with the result.
5. App processes the response and proceeds accordingly.
6. If needed, app may call ResetAuthenticateUserAndSignDataState() to clear cached signing state.

🧾 Overview

These APIs facilitate secure user authentication and payload signing, used in workflows like transaction approvals or consent validations.

📲 UI Screen Requirements

The app must:

• Display biometric prompt for authentication
• Clearly state the operation being signed (e.g., "Sign transaction")
• Show confirmation on success
• Handle retry on failure

🔐 1. AuthenticateUserAndSignData API

📘 Purpose

Initiates step-up authentication and data signing.

🔧 Parameters

🔐 Controlling Authentication

📊 authLevel Values

🧠

What isIDVServerBiometric?
IDVServerBiometric refers to biometric authentication that is registered with and validated by the IDV server. It ensures that the biometric used (e.g., fingerprint, face, palm) is:

• Enrolled and linked to the user on the server,
• Verified locally on device,
• And approved by the server as part of step-up authentication.

🧩 authenticatorType (Only valid value: 1)

🔒

Only value 1 is valid for data signing. All others are unsupported and should not be used.

💡 Sample Request

{
  "payload": "{"txnId":"TXN123456","amount":10000}",
  "authLevel": 4,
  "authenticatorType": 1,
  "reason": "Compliance biometric verification"
}

📥 Code Snippets

RdnaClient.authenticateUserAndSignData(
payload,
4,
1,
"Authorizing high-value payment"
);

rdna.authenticateUserAndSignData(
  payload,
  authLevel: 4,
  authenticatorType: 1,
  reason: "Authorizing high-value payment"
);

com.uniken.rdnaplugin.RdnaClient.authenticateUserAndSignData(
  payload,
  4,
  1,
  "Authorizing high-value payment"
);

NSString *payload = @"{"transactionId":"TX456","amount":2000}";
NSInteger authLevel = 4;
NSInteger authenticatorType = 1;
NSString *reason = @"Authorizing high-value payment";

[[RDNAClient sharedInstance] authenticateUserAndSignData:payload
                             authLevel:authLevel
                             authenticatorType:authenticatorType
                             reason:reason];

String payload = "{\"transactionId\":\"TX456\",\"amount\":2000}";
int authLevel = 4;
int authenticatorType = 1;
String reason = "Authorizing high-value payment";

RdnaClient.getInstance().authenticateUserAndSignData(
  payload,
  authLevel,
  authenticatorType,
  reason
);

📡 2. onAuthenticateUserAndSignData (Event)

📘 Purpose

Callback event triggered after authenticateUserAndSignData() is called. Provides result.

🧾 Sample Payload

{
  "userID": "john_doe",
  "payload": "{signed_data}",
  "status": {
    "statusCode": 100,
    "statusMessage": "Signed successfully"
  },
  "error": {
    "longErrorCode": 0,
    "shortErrorCode": 0,
    "errorString": "Success"
  }
}

🔄 3. ResetAuthenticateUserAndSignDataState API

📘 Purpose

Resets the cached state of a prior data signing operation. If any error occurs or the user wants to cancel or reset the flow, resetAuthenticateUserAndSignDataState needs to be called to acknowledge the SDK that the user is re-starting the sign data flow.

📥 Code Snippets

RdnaClient.resetAuthenticateUserAndSignDataState();

rdna.resetAuthenticateUserAndSignDataState();

com.uniken.rdnaplugin.RdnaClient.resetAuthenticateUserAndSignDataState();

- (void)resetAuthenticateUserAndSignDataState;

void resetAuthenticateUserAndSignDataState();

⚠️ Error Codes

✅ Developer Responsibilities