Computes RFC 2104-compliant HMAC signature
            
 Declaration Syntax
 Declaration Syntax| C# | 
public static string Sign( string data, SecureString key, KeyedHashAlgorithm algorithm )
 Parameters
 Parameters- data (String)
- The data to be signed
- key (SecureString)
- The secret signing key
- algorithm (KeyedHashAlgorithm)
- The algorithm to sign the data with
 Return Value
 Return ValueA string representing the HMAC signature