topic Re: HMAC SHA256 result SAP vs Java in Application Development and Automation Discussions

HMAC SHA256 result SAP vs Java

former_member283466 — Thu, 24 Mar 2016 13:40:34 GMT

Hello

I'm getting different HMAC code for the same input data and secret key comparing CL_ABAP_HMAC=>CALCULATE_HMAC_FOR_CHAR (using SHA256 algorithm) with result of javax.crypto.Mac (using HmacSHA256 algorithm).

Does anyone knows, if algorithms used by those classes are exactly the same. I would suspect that it should be that way, but as I'm getting different hash code in result for the same input I started to doubt. Or maybe I'm doing something wrong?

Thanks for any help

Regards,

Slawek

Re: HMAC SHA256 result SAP vs Java

mvoros — Thu, 24 Mar 2016 19:18:33 GMT

Hi,

ABAP version seems to be working fine. Maybe you are just mixing types and it does not matter. E.g. on this site

Free Online HMAC Generator / Checker Tool (MD5, SHA-1, SHA-256, etc.) - FreeFormatter.com

you can calculate HMAC-256. I did it for key = "ABC" and data = "ABC". The result is 87bed3bb8821d3196854b37290e5a1c3e518f99eff4101219d1d492fed1eba1a. To get the same value you have to first convert ABC to xstring using method STRING_TO_XSTRING. This gives you 414243. Then if you just set key to 414243 and data to ABC then the returned MAC from CALCULATE_HMAC_FOR_CHAR is same as the one above. I did this all in SE24 just by testing the class.

Cheers

Re: HMAC SHA256 result SAP vs Java

former_member1044857 — Thu, 09 May 2019 09:13:16 GMT

This was of great help !