SQL Server versions with data encryption/decryption support

1. Data in column A in table T1 is encrypted 2. Data in column B in table T2 is normal text. Its size is varchar(6)

3. One of the conditions in our WHERE clause is to compare the first 6 characters of column A in table T1 with column B in table T2

How do I acheive that? Is there any built-in SQL Server function for encryption/decryption? The query is part of stored procedure. Triple DES is the algorithm used for data encryption. We are using SQL Server 2000. Any help is greatly appreciated!