Question

I’m working on implementing encryption in MS SQL 2008R2. Loading data from a CVS file, I have that data in a temp table, and I now want to move some of that data into a encrypted credit card table. However, I keep getting the following error. Code for insert follows, table defs below.

The client ID is below 10 – the number causing the overflow is the very first line of data, CC number.

Error:

Msg 248, Level 16, State 1, Line 4
The conversion of the varchar value ‘5105105105105100’ overflowed an int column.
The statement has been terminated.

Insert statement:

OPEN SYMMETRIC KEY CreditCardKey
        DECRYPTION BY CERTIFICATE CreditCardCert;

    insert into CreditCard
    Select
        HASHBYTES('SHA1', t.CreditCard),
        EncryptByKey(key_guid('CreditCardKey'), t.CreditCard),
        '',
        RIGHT(4, t.CreditCard),
        '1',
        t.Expiration,
        convert(int, t.ClientID)
    From TempTbl t

TempTbl:

• ClientID int.
• First, Last, CC, Expiration — all varchar(50).

All data appears to have imported correctly.

CreditCard: (destination table)

Hash varbinary(200)
Encrypted varbinary(400)
plaintext char(16)
lastfour int
servicecode int
expirationdate Date
ClientID int

Answer 1

Syntax issue was causing the overflow:
My use of the RIGHT function reversed the character and int offset, overflowing the integer expression of the function.

Correct use:

RIGHT ( character_expression , integer_expression )