(VB.NET UWP/WinRT) HMAC Hex String

Demonstrates how to compute an HMAC using a hexidecimal key and data.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

Dim crypt As New Chilkat.Crypt2

Dim success As Boolean = crypt.UnlockComponent("Anything for 30-day trial")
If (success <> True) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


'  Set the MAC algorithm to HMAC
crypt.MacAlgorithm = "hmac"


'  Our HMAC key will be the bytes represented in the following hex string.
'  In other words, the HMAC key is composed of the bytes 0x41, 0xC2, 0x1C, ...
'  (It is not composed of the us-ascii string '4', '1', 'C', ...)
Dim keyHex As String = "41C21CB9D7A02FC5D4FADB9E4755B9DE"
success = crypt.SetMacKeyEncoded(keyHex,"hex")

'  Our desire is to HMAC the bytes represented in the following string:
Dim dataHex As String = "C22078065B01460001000000010062043BF5B18228C8E02D17BCFE4E00561FA6DEC216EA97195CEB579942E275C21932258E3CD391E507FF4E7FD4C787A8447DA111C54A9C1795E7FF4C0BAA2EDA"

'  We'll need to decode the hex to binary:
Dim bd As New Chilkat.BinData
bd.AppendEncoded(dataHex,"hex")

'  Do the HMAC-SHA256 hash and return as a hex string:
crypt.EncodingMode = "hex"
crypt.HashAlgorithm = "sha-256"
Dim macHex As String = crypt.MacBdENC(bd)
Debug.WriteLine(macHex)