Adding Flex Token Verification code to SDK

Author: gnongsie

Utilities/Flex/Exception/FlexException.cs

@@ -0,0 +1,26 @@
+using System.Runtime.Serialization;
+
+namespace CyberSource.Utilities.Flex.Exception
+{
+    public abstract class FlexException : System.Exception, ISerializable
+    {
+        /// <summary>
+        /// Constructs a new instance of the exception with a specified error message.
+        /// </summary>
+        /// <param name="message">The error message that explains the reason for the exception</param>
+        public FlexException(string message) : base(message) { }
+
+        /// <summary>
+        /// Constructs a new instance of the exception with a specified error message 
+        /// and a reference to the inner exception that is the cause of this exception.
+        /// </summary>
+        /// <param name="message">The error message that explains the reason for the exception</param>
+        /// <param name="inner">The exception that is the cause of the current exception</param>
+        public FlexException(string message, System.Exception inner) : base(message, inner) { }
+
+        protected FlexException(SerializationInfo serializationInfo, StreamingContext streamingContext)
+            : base(serializationInfo, streamingContext)
+        {
+        }
+    }
+}

Utilities/Flex/Exception/FlexInternalException.cs

@@ -0,0 +1,19 @@
+using System.Runtime.Serialization;
+
+namespace CyberSource.Utilities.Flex.Exception
+{
+    /// <summary>
+    /// Exception that is thrown when there is an error performing an internal SDK function.
+    /// </summary>
+    public class FlexInternalException : FlexException
+    {
+        public FlexInternalException(string message) : base(message) { }
+
+        public FlexInternalException(string message, System.Exception inner) : base(message, inner) { }
+
+        protected FlexInternalException(SerializationInfo serializationInfo, StreamingContext streamingContext)
+            : base(serializationInfo, streamingContext)
+        {
+        }
+    }
+}

Utilities/Flex/Model/FlexDerPublicKey.cs

@@ -0,0 +1,41 @@
+namespace CyberSource.Utilities.Flex.Model
+{
+    /// <summary>
+    /// Represents the public RSA key in DER format.
+    /// </summary>
+    public class FlexDerPublicKey
+    {
+        /// <summary>
+        /// Gets and sets the public key format.
+        /// </summary>
+        public string format { get; set; }
+        
+        /// <summary>
+        /// Gets and sets the algorithm with which the key is used.
+        /// </summary>
+        public string algorithm { get; set; }
+        
+        /// <summary>
+        /// Gets and sets the encoded key specification.
+        /// </summary>
+        public string publicKey { get; set; }
+
+        /// <summary>
+        /// Default constructor. Use if you wish to set properties individually.
+        /// </summary>
+        public FlexDerPublicKey() { }
+
+        /// <summary>
+        /// Constructs a DerPublicKey instance with the supplied format, algorithm and encoded key.
+        /// </summary>
+        /// <param name="format">The format</param>
+        /// <param name="algorithm">The algorithm</param>
+        /// <param name="publicKey">The encoded key</param>
+        public FlexDerPublicKey(string format, string algorithm, string publicKey)
+        {
+            this.format = format;
+            this.algorithm = algorithm;
+            this.publicKey = publicKey;
+        }
+    }
+}

Utilities/Flex/Model/FlexPublicKey.cs

@@ -0,0 +1,43 @@
+namespace CyberSource.Utilities.Flex.Model
+{
+    public class FlexPublicKey
+    {
+        /// <summary>
+        /// Gets or sets the unique ID of the key.
+        /// </summary>
+        public string keyId { get; set; }
+    
+        /// <summary>
+        /// Gets or sets the DER representation of the key.
+        /// </summary>
+        public FlexDerPublicKey der { get; set; }
+        
+        /// <summary>
+        /// Gets or sets the JSON Web Key representation of the key for use with the Web Crypto API.
+        /// </summary>
+        public JsonWebKey jwk { get; set; }
+
+        /// <summary>
+        /// Default constructor. Use if you wish to set properties individually.
+        /// </summary>
+        public FlexPublicKey() { }
+
+        /// <summary>
+        /// Constructs a FlexPublicKey instance with the specified ID, DER representation and JWK representation.
+        /// </summary>
+        /// <param name="keyId">The ID</param>
+        /// <param name="der">The DER representation</param>
+        /// <param name="jwk">The JWK representation</param>
+        public FlexPublicKey(string keyId, FlexDerPublicKey der, JsonWebKey jwk)
+        {
+            this.keyId = keyId;
+            this.der = der;
+            this.jwk = jwk;
+        }
+
+        public override string ToString()
+        {
+            return System.String.Format("FlexPublicKey[keyId={0}]", keyId);
+        }
+    }
+}

Utilities/Flex/Model/FlexToken.cs

@@ -0,0 +1,60 @@
+using System.Collections.Generic;
+
+namespace CyberSource.Utilities.Flex.Model
+{
+    /// <summary>
+    /// Represents the Flex API token response.
+    /// </summary>
+    public class FlexToken
+    {
+        /// <summary>
+        /// Gets or sets the ID of the key associated with the token.
+        /// </summary>
+        public string keyId { get; set; }
+        
+        /// <summary>
+        /// Gets or sets the generated token. The token replaces card data and is used as the Subscription ID in the CyberSource Simple Order API or SCMP API.
+        /// </summary>
+        public string token { get; set; }
+        
+        /// <summary>
+        /// Gets or sets the masked card number.
+        /// </summary>
+        public string maskedPan { get; set; }
+        
+        /// <summary>
+        /// Gets or sets the card type.
+        /// </summary>
+        public string cardType { get; set; }
+        
+        /// <summary>
+        /// Gets or sets the UTC date and time in milliseconds at which the signature was generated.
+        /// </summary>
+        public long timestamp { get; set; }
+        
+        /// <summary>
+        /// Gets or sets the list of follow-on services with which the token may be used.
+        /// </summary>
+        public IDictionary<string, object> discoverableServices { get; set; }
+        
+        /// <summary>
+        /// Gets or sets which fields from the response make up the data that is used when verifying the response signature.
+        /// </summary>
+        public string signedFields { get; set; }
+        
+        /// <summary>
+        /// Gets or sets the Flex-generated digital signature. To ensure the values have not been tampered with while passing through the client, verify the signature server-side using the associated Flex API public key.
+        /// </summary>
+        public string signature { get; set; }
+        
+        /// <summary>
+        /// Gets or sets the embedded object(s).
+        /// </summary>
+        public IDictionary<string, object> _embedded { get; set; }
+
+        /// <summary>
+        /// Constructs a FlexToken instance.
+        /// </summary>
+        public FlexToken() { }
+    }
+}

Utilities/Flex/Model/JsonWebKey.cs

@@ -0,0 +1,55 @@
+namespace CyberSource.Utilities.Flex.Model
+{
+    /// <summary>
+    /// Represents a JSON Web Key for use with the Web Crypto API.
+    /// </summary>
+    public class JsonWebKey
+    {
+        /// <summary>
+        /// Gets or sets the key type.
+        /// </summary>
+        public string kty { get; set; }
+    
+        /// <summary>
+        /// Gets or sets the key use.
+        /// </summary>
+        public string use { get; set; }
+        
+        /// <summary>
+        /// Gets or sets the key ID.
+        /// </summary>
+        public string kid { get; set; }
+        
+        /// <summary>
+        /// Gets or sets the modulus.
+        /// </summary>
+        public string n { get; set; }
+        
+        /// <summary>
+        /// Gets or sets the exponent.
+        /// </summary>
+        public string e { get; set; }
+
+        /// <summary>
+        /// Default constructor. Use if you wish to set properties individually.
+        /// </summary>
+        public JsonWebKey() { }
+
+        /// <summary>
+        /// Constructs a JsonWebKey instance with the specified key type, key use, key ID, modulus and exponent.
+        /// </summary>
+        /// <param name="keyType">The key type</param>
+        /// <param name="keyUse">The key use</param>
+        /// <param name="keyId">The key ID</param>
+        /// <param name="modulus">The modulus</param>
+        /// <param name="exponent">The exponent</param>
+        public JsonWebKey(string keyType, string keyUse, string keyId, string modulus, string exponent)
+        {
+            this.kty = keyType;
+            this.use = keyUse;
+            this.kid = keyId;
+            this.n = modulus;
+            this.e = exponent;
+        }
+    }
+}

Utilities/Flex/TokenVerification/TokenVerificationUtility.cs

@@ -1,18 +1,16 @@
-using FlexServerSDK.Exception;
-using FlexServerSDK.Model;
+using CyberSource.Utilities.Flex.Exception;
+using CyberSource.Utilities.Flex.Model;
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using System.Security.Cryptography;
 using System.Text;
-using System.Threading.Tasks;
 
 namespace CyberSource.Utilities.Flex.TokenVerification
 {
-    public static class TokenVerificationUtility
+    public class TokenVerificationUtility
     {
-        public static bool Verify(FlexPublicKey flexKey, IDictionary<string, string> postParameters)
+        public bool Verify(FlexPublicKey flexKey, IDictionary<string, string> postParameters)
         {
             var publicKeyStr = flexKey.der.publicKey;
             RSAParameters publicKey = DecodePublicKey(Convert.FromBase64String(publicKeyStr)).ExportParameters(false);
@@ -52,11 +50,11 @@ private static bool ValidateTokenSignature(RSAParameters publicKey, string signe
                 }
                 catch (CryptographicException e)
                 {
-                    throw new FlexSDKInternalException("Error validating signature", e);
+                    throw new FlexInternalException("Error validating signature", e);
                 }
                 catch (System.Exception e)
                 {
-                    throw new FlexSDKInternalException("Error validating signature", e);
+                    throw new FlexInternalException("Error validating signature", e);
                 }
                 finally
                 {
@@ -196,7 +194,7 @@ private static RSACryptoServiceProvider DecodePublicKey(byte[] x509key)
                 rsa.ImportParameters(rsaKeyInfo);
                 return rsa;
             }
-            catch (Exception)
+            catch (System.Exception)
             {
                 return null;
             }