Encrypting a column

[achick]

I am trying to encrypt a column in SQL server 08.
I am using AES, certificate and symmetric key.
Can I change the data type and length of the encrypted column from varbinary(128) to a smaller length and also change it to varchar?
Is there a way to prefix the encrypted column data?
Is there a way to encrypt so that same value gets same encrypted ID?
For example, if the table has the same ID in different rows- can I get the same encryptedID for that ID wherever it is used?

 

[djj55]

Every time a value is encrypted it returns a different represntation value. What you see in the column as VARBINARY is a representation of the value not the actual value so you should not convert to VARCHAR.
We went with a HASH stratagy for comparing two rows (see HASHBYTES). We use a seed that we rotate monthly (all values rehashed) so it is harder to use a rainbow table.

djj
The Lord is my shepherd (Psalm 23) - I need someone to lead me!

 

[achick]

Thank you. I am going to try that.