[tolle]

They could just swap out the authentication mechanism instead of the entire COBOL stack. I don't really know why you wouldn't just run the auth bits in some other language. The programs that calculate your monthly interest on your mortgage doesn't exactly have to have to be able to handle your login credentials.

[zaarn]

AFAIK it's because their entire system is rather legacy, so over the years they tacked on fixes while "the replacement will be done soon(TM)".

Banks do have some problem with these sorts of projects, so I think they're trying to build something that will last as long as the COBOL system at less cost.