Mastercard Internet Gateway Service: Hashing Design Flaw

Last year I found a design error in the MD5 version of the hashing method used by Mastercard Internet Gateway Service. The flaw allows modification of transaction amount. ¬†They have awarded me with a bounty for reporting it. This year, they have switched to HMAC-SHA256, but this one also has a flaw (and no response … Continue reading Mastercard Internet Gateway Service: Hashing Design Flaw