Hiding token information from users

[Tobiah]

On 08/23/2011 08:08 AM, Ian Kelly wrote:
> How many of these codes do you need, and do they only need to be
> decrypted at a central server? You might be able to just create random
> strings of whatever form you want and associate them with the tokens in
> a database. Then they will be completely opaque.
>

The tokens have a year portion that increments each year, and
the base portion of the token will be created newly in accordance
with new accounts that we take on.  I really need some sort of
algorithm that will let me take an unknown string and generate
the encrypted bit on the fly.

Thanks,

Tobiah