Base-64 Encoding of SHA256 in Power Automate

Question

We are trying to implement a hashing algorithm that takes the string 35FEBEA52A07816B0949505E46E6C8CB2B9D3896A625286BFA4CB04202452157 and produces the output Nf6+pSoHgWsJSVBeRubIyyudOJamJShr+kywQgJFIVc=. The documentation states this is the Base-64 encoding of the string, however, using the base64 expression in Power Automate with the above input string yields the output MzVGRUJFQTUyQTA3ODE2QjA5NDk1MDVFNDZFNkM4Q0IyQjlEMzg5NkE2MjUyODZCRkE0Q0IwNDIwMjQ1MjE1Nw==.

My colleague was able to achieve the conversion through command-line with the following command: echo "35FEBEA52A07816B0949505E46E6C8CB2B9D3896A625286BFA4CB04202452157" | xxd -r -p | base64 - however, I can't find any equivalent of this in Power Automate. Any ideas are appreciated. Thanks!

Answer 1

Yep, I have an answer for you but you may not like it. The easiest way is to use a third party connector called Advanced Data Operations and in particular, the C# Script Execute operation.

https://statesolutions.com.au/c-script-execute/

https://statesolutions.com.au/pricing/

You can sign up for a free trial and give it a whirl by going to the Pricing page.

Script

var hexString = parameters.hexString;

byte[] byteArray = new byte[hexString.Length / 2];

for (int i = 0; i < byteArray.Length; i++)
{
    byteArray[i] = Convert.ToByte(hexString.Substring(i * 2, 2), 16);
}

var base64String = Convert.ToBase64String(byteArray);

return base64String;

Parameters

{
  "hexString": @{variables('Hex String')}
}

Result