In this .NET example, calling the HMACSHA1_HashString function will return the proper hash signature value to connect to the API and submit the request.

// Define the API Variables and Parameters
Dim APIUsername As String = "efQvdjyar"
Dim APIPassword As String = "IvQ01brhg"
Dim APIKey As String = "lvPaGd3DXhP17uCF5br8cv0Rt"
Dim time As DateTime = DateTime.Now
Dim format As String = "yyyy-MM-ddTHH:mm:ssZ"
Dim formattedtime as string = time.ToString(format)
Dim strToHash As String = APIUsername & APIPassword & formattedtime

// Call the Function to get the Hash Signature
Console.WriteLine(HMACSHA1_HashString(strToHash, APIKey))

// Here is the function
Public Function HMACSHA1_HashString(ByVal StringToHash As String, ByVal HashKey As String) As String
	Dim myEncoder As New System.Text.UTF8Encoding
	Dim Key() As Byte = myEncoder.GetBytes(HashKey)
	Dim Text() As Byte = myEncoder.GetBytes(StringToHash)
	Dim myHMACSHA1 As New System.Security.Cryptography.HMACSHA1(Key)
	Dim HashCode As Byte() = myHMACSHA1.ComputeHash(Text)
	Return Convert.ToBase64String(HashCode)
End Function