Unable to parse or decrypt encCard error - Visa In-App Provisioning

[mustafagundogdu]

Hello friends

When doing In-App Provisioning for Google Pay, How can I prepare encCard data?

Can you share an example algorithm for c#?

I created ApiKey and SharedSecretKey but I get this response from the service. Can you support me if I am going wrong?

ErrorRepsonse: 

"errorResponse": {
"status": 400,
"reason": "invalidParameterEncCard",
"message": "Invalid input parameter(s)",
"details": [{
"location": "encCard",
"message": "Unable to parse or decrypt"
}]}

[API_Products]

Hey @mustafagundogdu,

When working with Visa In-App Provisioning for Google Pay, the `encCard` field must be properly encrypted. The error you received indicates that the `encCard` value could not be parsed or decrypted, which suggests an issue with how the encryption was performed.

Here’s an example of how to prepare and encrypt the `encCard` data using C#:

1. Generate RSA Key Pair: Usually, this will be provided by Visa. If you need to generate it, use a library like BouncyCastle.

2. Encrypt the Card Data: Use the RSA public key to encrypt the card data.

3. Encode the Encrypted Data: Encode the encrypted data into Base64 format.

Here’s a simplified example of encrypting card data using C#:

```csharp
// START 
using System;
using System.Security.Cryptography;
using System.Text;

public class VisaEncryption
{
public static string EncryptCardData(string cardData, string publicKey)
{
// Convert the public key to RSAParameters
var rsaParameters = new RSAParameters
{
Modulus = Convert.FromBase64String(publicKey),
Exponent = new byte[] { 1, 0, 1 } // Common exponent
};

// Create an RSA instance and import the parameters
using (var rsa = new RSACryptoServiceProvider())
{
rsa.ImportParameters(rsaParameters);

// Encrypt the card data
var encryptedData = rsa.Encrypt(Encoding.UTF8.GetBytes(cardData), false);

// Convert to Base64 string
return Convert.ToBase64String(encryptedData);
}
}

public static void Main(string[] args)
{
string cardData = "4957030420210454"; // Example card data
string publicKey = "YOUR_RSA_PUBLIC_KEY"; // Replace with your RSA public key

string encCard = EncryptCardData(cardData, publicKey);

Console.WriteLine("Encrypted Card Data: " + encCard);
}
}
// END 
```

Steps to follow:

1. Replace `YOUR_RSA_PUBLIC_KEY`: Replace this with your actual RSA public key provided by Visa.

2. Encrypt Card Data: The `EncryptCardData` method will encrypt the card data using the RSA public key and return a Base64 encoded string.

3. Use Encrypted Data: The returned `encCard` value is what you should use in your API request.

If the issue persists, ensure that:

- The RSA public key is correctly formatted and used.
- The card data is correctly formatted before encryption.
- The API Key and Shared Secret Key are correctly configured.