ALTER CERTIFICATE (Transact-SQL)

Article
05/16/2013

Changes the private key used to encrypt a certificate, or adds one if none is present. Changes the availability of a certificate to Service Broker.

Topic link icon Transact-SQL Syntax Conventions

Syntax

ALTER CERTIFICATE certificate_name 
    REMOVE PRIVATE KEY
    |
    WITH PRIVATE KEY ( <private_key_spec> [ ,... ] )
    |
    WITH ACTIVE FOR BEGIN_DIALOG = [ ON | OFF ]

<private_key_spec> ::= 
    FILE = 'path_to_private_key' 
    |
    DECRYPTION BY PASSWORD = 'key_password' 
    |
    ENCRYPTION BY PASSWORD = 'password'

Arguments

certificate_name
Is the unique name by which the certificate is known in database.
FILE ='path_to_private_key'
Specifies the complete path, including file name, to the private key. This parameter can be a local path or a UNC path to a network location. This file will be accessed within the security context of the SQL Server service account. When you use this option, you must make sure that the service account has access to the specified file.
DECRYPTION BY PASSWORD ='key_password'
Specifies the password that is required to decrypt the private key.
ENCRYPTION BY PASSWORD ='password'
Specifies the password used to encrypt the private key of the certificate in the database. password must meet the Windows password policy requirements of the computer that is running the instance of SQL Server. For more information, see Password Policy.
REMOVE PRIVATE KEY
Specifies that the private key should no longer be maintained inside the database.
ACTIVE FOR BEGIN_DIALOG = { ON | OFF }
Makes the certificate available to the initiator of a Service Broker dialog conversation.

Remarks

The private key must correspond to the public key specified by certificate_name.

The DECRYPTION BY PASSWORD clause can be omitted if the password in the file is protected with a null password.

When the private key of a certificate that already exists in the database is imported from a file, the private key will be automatically protected by the database master key. To protect the private key with a password, use the ENCRYPTION BY PASSWORD phrase.

The REMOVE PRIVATE KEY option will delete the private key of the certificate from the database. You can do this when the certificate will be used to verify signatures or in Service Broker scenarios that do not require a private key. Do not remove the private key of a certificate that protects a symmetric key.

You do not have to specify a decryption password when the private key is encrypted by using the database master key.

Important

Always make an archival copy of a private key before removing it from a database. For more information, see BACKUP CERTIFICATE (Transact-SQL).

The WITH PRIVATE KEY option is not available in a contained database.

Permissions

Requires ALTER permission on the certificate.

Examples

A. Changing the password of a certificate

ALTER CERTIFICATE Shipping04 
    WITH PRIVATE KEY (DECRYPTION BY PASSWORD = 'pGF$5DGvbd2439587y',
    ENCRYPTION BY PASSWORD = '4-329578thlkajdshglXCSgf');
GO

B. Changing the password that is used to encrypt the private key

ALTER CERTIFICATE Shipping11 
    WITH PRIVATE KEY (ENCRYPTION BY PASSWORD = '34958tosdgfkh##38',
    DECRYPTION BY PASSWORD = '95hkjdskghFDGGG4%');
GO

C. Importing a private key for a certificate that is already present in the database

ALTER CERTIFICATE Shipping13 
    WITH PRIVATE KEY (FILE = 'c:\\importedkeys\Shipping13',
    DECRYPTION BY PASSWORD = 'GDFLKl8^^GGG4000%');
GO

D. Changing the protection of the private key from a password to the database master key

ALTER CERTIFICATE Shipping15 
    WITH PRIVATE KEY (DECRYPTION BY PASSWORD = '95hk000eEnvjkjy#F%');
GO

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