I recently learned about the hashing algorithm bcrypt, which allows you to specify a "work factor" for the hash which can be incremented to stay ahead of Moore's Law. I understand there are some other hashing algorithms that also do this.
Are there any two-way encryption algorithms with this property? For example, I'd like to be able to encrypt a file such that it takes a couple of seconds with today's machines to decrypt it using the correct key, and therefore someone who is trying to guess the key will be severely rate-limited.