Transaction Hash Upgrade Guide for API using VB.NET. Hashes don't match

JenHaga — Wed, 13 Mar 2019 17:56:42 GMT

Help please. I can't get the Hash values to match. I'm trying to follow the instructions from the API Upgrade guide here: https://developer.authorize.net/support/hash_upgrade/

Step 1 - I've generated my signature key and stored it in my web.config

Step 2 - Convert the Signature Key into a byte array. I've skipped this step because, "For C# users, Authorize.Net provides the following code for converting the Signature Key into a byte array and calculating the HMAC-SHA512 hash."

Step 3 - create a message string from the API Login ID, the transaction ID and the amount.

I'm pulling my APILoginID from where I stored it in my web.config
I'm pulling the transaction ID this way: Dim APITransID As String = response.transactionResponse.transId
The guide says to use "The transaction amount that we send in createTransactionResponse in the amount element. " However, there is no amount element in response.transactionResponse, so I'm using the same amount variable I'm using to send in the transaction:

Dim transactionRequest = New transactionRequestType With {
.transactionType = AuthOrAuthCapture,
.amount = amount,
.payment = paymentType,
.billTo = billingAddress,
.order = OrderInfo
}

So my message string looks like this:

Dim MessageString As String = String.Format("^{0}^{1}^{2}^", ApiLoginID, APITransID, amount)

Step 4 - "Use HMAC-SHA512 to hash the byte array form of the Signature Key from Step 2 with the message string from Step 3" - But I'm combining step 2 & step 4 using the provided c# code (converted to vb):

SignatureKey is being pulled from my web.config
I'm calling the funciton with this line:
Dim hashedSignatureAndMessage As String = HMACSHA512(SignatureKey, MessageString)

Public Function HMACSHA512(ByVal key As String, ByVal textToHash As String) As String
If String.IsNullOrEmpty(key) Then Throw New ArgumentNullException("HMACSHA512: key", "Parameter cannot be empty.")
If String.IsNullOrEmpty(textToHash) Then Throw New ArgumentNullException("HMACSHA512: textToHash", "Parameter cannot be empty.")

If key.Length Mod 2 <> 0 OrElse key.Trim().Length < 2 Then
Throw New ArgumentNullException("HMACSHA512: key", "Parameter cannot be odd or less than 2 characters.")
End If

Try
Dim k As Byte() = Enumerable.Range(0, key.Length).Where(Function(x) x Mod 2 = 0).[Select](Function(x) Convert.ToByte(key.Substring(x, 2), 16)).ToArray()

Dim hmac As HMACSHA512 = New HMACSHA512(k)

Dim HashedValue As Byte() = hmac.ComputeHash((New System.Text.ASCIIEncoding()).GetBytes(textToHash))
Return BitConverter.ToString(HashedValue).Replace("-", String.Empty)
Catch ex As Exception
Throw New Exception("HMACSHA512: " & ex.Message)
End Try
End Function

Step 5 - Compare the value of transHashSHA2 with the output from the HMAC-SHA512 hash mentioned in Step 4:

Dim myTransHashSha2 As String = response.transactionResponse.transHashSha2

myTransHashSha2 should equal hashedSignatureAndMessage , but it doesn't.

Where is the issue in my code? Thanks in advance!

Re: Transaction Hash Upgrade Guide for API using VB.NET. Hashes don't match

Renaissance — Sun, 17 Mar 2019 18:13:15 GMT

@JenHaga

with a full disclosure that I’ve never written an app in C# when you are calculating the remainder (I think that is what you are doing with x Mod 2 = 0) you appear to be assigning a value when you need to be comparing a value. So change to Mod 2 == 0 and see what happens.

Re: Transaction Hash Upgrade Guide for API using VB.NET. Hashes don't match

JenHaga — Mon, 18 Mar 2019 14:07:33 GMT

Thanks for your reply. Yes in c# you need == but vb uses = for both comparing and assigning. However, maybe I need to take another look at my translation from the posted c# to my vb.

Re: Transaction Hash Upgrade Guide for API using VB.NET. Hashes don't match

JenHaga — Wed, 20 Mar 2019 13:38:56 GMT

So there must have been something in that translation. I created a separate project in c# that held just the function copied directly from the upgrade guide. Then I published and included the .dll in my vb project. So I'm calling the function like this:

Dim hashedSignatureAndMessage As String = ANHMACSHA512.HMACSHA512(SignatureKey, MessageString)

Now the hashes are matching!

topic Transaction Hash Upgrade Guide for API using VB.NET. Hashes don't match in Integration and Testing

Transaction Hash Upgrade Guide for API using VB.NET. Hashes don't match

Re: Transaction Hash Upgrade Guide for API using VB.NET. Hashes don't match

Re: Transaction Hash Upgrade Guide for API using VB.NET. Hashes don't match

Re: Transaction Hash Upgrade Guide for API using VB.NET. Hashes don't match