EncryptByPassPhrase (Transact-SQL)
Encrypt data with a passphrase.
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Transact-SQL Syntax Conventions
Syntax
EncryptByPassPhrase ( { 'passphrase' | @passphrase } ,
{ 'cleartext' | @cleartext }
[ , { add_authenticator | @add_authenticator }
, { authenticator | @authenticator } ]
)
Arguments
- passphrase
A passphrase from which to generate a symmetric key.
- @passphrase
A variable of type nvarchar, char, varchar, binary, varbinary, or nchar containing a passphrase from which to generate a symmetric key.
- cleartext
The cleartext to be encrypted.
- @cleartext
A variable of type nvarchar, char, varchar, binary, varbinary, or nchar containing the cleartext. Maximum size is 8,000 bytes.
- add_authenticator
Indicates whether an authenticator will be encrypted together with the cleartext. 1 if an authenticator will be added. int.
- @add_authenticator
Indicates whether a hash will be encrypted together with the cleartext.
- authenticator
Data from which to derive an authenticator. sysname.
- @authenticator
A variable containing data from which to derive an authenticator.
Return Types
varbinary with maximum size of 8,000 bytes.
Remarks
A passphrase is a password that includes spaces. The advantage of using a passphrase is that it is easier to remember a meaningful phrase or sentence than to remember a comparably long string of characters.
This function does not check password complexity.
Examples
The following example updates a record in the SalesCreditCard table and encrypts the value of the credit card number stored in column CardNumber_EncryptedbyPassphrase, using the primary key as an authenticator.
USE AdventureWorks;
GO
-- Create a column in which to store the encrypted data.
ALTER TABLE Sales.CreditCard
ADD CardNumber_EncryptedbyPassphrase varbinary(256);
GO
-- First get the passphrase from the user.
DECLARE @PassphraseEnteredByUser nvarchar(128);
SET @PassphraseEnteredByUser
= 'A little learning is a dangerous thing!';
-- Update the record for the user's credit card.
-- In this case, the record is number 3681.
UPDATE Sales.CreditCard
SET CardNumber_EncryptedbyPassphrase = EncryptByPassPhrase(@PassphraseEnteredByUser
, CardNumber, 1, CONVERT( varbinary, CreditCardID))
WHERE CreditCardID = '3681';
GO
See Also
Reference
DecryptByPassPhrase (Transact-SQL)