SQL Server

Set the OAEP Hash Algorithm for Encrypted Email

Demonstrates the Chilkat Email.OaepHash property, which selects the hash algorithm used by OAEP padding when encrypting email with RSAES-OAEP. Valid values are sha1, sha256, sha384, and sha512; the default is sha256. This property is used only when OaepPadding is true, so this example enables OAEP first.

Background: OAEP ("Optimal Asymmetric Encryption Padding") uses a hash function internally as part of the randomized padding it wraps around the data before RSA encryption. The choice of hash affects security and, importantly, interoperability: the sender and recipient must use the same OAEP hash, or decryption fails. That is why this is exposed as an explicit setting rather than left implicit.

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--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @sTmp0 nvarchar(4000)
    --  Demonstrates the Email.OaepHash property, which selects the hash algorithm used by
    --  OAEP padding when encrypting email with RSAES-OAEP.  Valid values: sha1, sha256,
    --  sha384, sha512.  The default is sha256.  It is used only when OaepPadding is true.

    DECLARE @email int
    EXEC @hr = sp_OACreate 'Chilkat.Email', @email OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    EXEC sp_OASetProperty @email, 'Subject', 'Encrypted with RSAES-OAEP'

    --  OAEP padding must be enabled for the OAEP hash to take effect.
    EXEC sp_OASetProperty @email, 'OaepPadding', 1
    EXEC sp_OASetProperty @email, 'OaepHash', 'sha256'


    EXEC sp_OAGetProperty @email, 'OaepHash', @sTmp0 OUT
    PRINT 'OaepHash = ' + @sTmp0

    EXEC @hr = sp_OADestroy @email


END
GO