I am developing a site for which I would like to protect buyers by anonymizing their email addresses.Similar to craigslist's system, when a seller needs to contact a buyer they should be able to send an email to an anonymized address such as 1425415125@mysite.com which will then be routed to the user's email address. 

My plan right now is to:

1. Set up a bucket (catch-all) inbox
2. Generate a random key for each buyer which will be the user specific ('1425415125' above) section of the email address
3. Monitor the bucket inbox and parse out this user specific section. Once I know the user, the email can be forwarded to the correct address

My questions are as follows:

1. Can you see any issues with the above solution
2. Are there any open source solutions to the existing problem
3. Are there any gotchas that one should be aware of when developing such a system?

Thanks in advance

JP