10 years is probably too short, but you're right that copyright laws are broken. I do like 10 years as a good number to work from.
I think copyright should be broken into personal and corporate copyright. Personal copyright is owned by the author. Corporate by a corporation.
Personal copyright should have a maximum 10 year exclusive license limit, after ten years the license should be renegotiated, and perhaps transfered to another publisher. He time limit for personal copyright should be Death or twenty years whichever is longer.
Corporate copyright should be free for 10 years. And then renewed in each country that the corporation wants to enforce it in for $10,000 for then next 10 years, then $100,000 for ten more years and so on. So:
0-10 years free
11-20 years $10,000 per country
21-30 years $100,000 per country
31-40 years $1,000,000 per country ...
If a company wants to bankrupt itself to keep a copyright that's fine but it'll quickly become too expensive for companies not to let copyrit lapse.
Breaking digital locks should not be illegal. You blame the lock if it gts broken, safes and locks are rated by how long it takes to break into them. Also you could look at it as a National Security question, if you my cryptography illegal, only crimals will be cryptologists. And then how are you going to secure your communications? Digital locks are a good way to train the next generation of cryptologists, and keep them practiced.