> If you cannot understand this, please I beg you, do NOT design crypto systems. If you'd like to be an even better Good Samaritan, please disclose your identity to the community. This may protect your future employer and their customers from a breach.

First let me say that I believed we were having a decent conversation until this comment right here. You're personally attacking me at this point. I am not designing crypto. In my first message I stated multiple times that those were my thoughts. My identity isn't hidden - if you care to look through my history. Your account is 20 days old, and you're talking to me about making my identity public?

Anyhow, I now understand the attack you've been describing. I misunderstood the attack, thinking you wanted to be able to sign any message of your choosing. Rather, the attack is focused on iteratively changing the signature of a message until the server confirms it. I was wrong, you were right. The spec for JSON Web Algorithms (JWA)[0] confirms this.

[0] https://tools.ietf.org/html/draft-ietf-jose-json-web-algorit...