SQL Server

AES-CMAC

See more Encryption Examples

Demonstrates using the AES-CMAC algorithm, which is a keyed hash function similar to HMAC and Poly1305.

Note: Chilkat added AES-CMAC in version 9.5.0.95.

SQL Server

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @success int
    SELECT @success = 0

    -- This example assumes the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @crypt int
    EXEC @hr = sp_OACreate 'Chilkat.Crypt2', @crypt OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- Set the MAC algorithm to AES-CMAC
    EXEC sp_OASetProperty @crypt, 'MacAlgorithm', 'aes-cmac'

    -- AES-CMAC always uses a 16-byte (128-bit) MAC key.
    DECLARE @keyHex nvarchar(4000)
    SELECT @keyHex = '2b7e151628aed2a6abf7158809cf4f3c'
    EXEC sp_OAMethod @crypt, 'SetMacKeyEncoded', @success OUT, @keyHex, 'hex'

    -- Let's compute the AES-CMAC for the test vector at https://www.rfc-editor.org/rfc/rfc4493#appendix-A
    -- Here we have 64 bytes in hex representation.
    DECLARE @messageBytes nvarchar(4000)
    SELECT @messageBytes = '6bc1bee22e409f96e93d7e117393172aae2d8a571e03ac9c9eb76fac45af8e5130c81c46a35ce411e5fbc1191a0a52eff69f2445df4f9b17ad2b417be66c3710'

    DECLARE @bd int
    EXEC @hr = sp_OACreate 'Chilkat.BinData', @bd OUT

    EXEC sp_OAMethod @bd, 'AppendEncoded', @success OUT, @messageBytes, 'hex'

    -- Compute the AES-CMAC for the bytes contained in bd and return the AES-CMAC in hex representation.
    EXEC sp_OASetProperty @crypt, 'EncodingMode', 'hex_lower'
    DECLARE @cmac nvarchar(4000)
    EXEC sp_OAMethod @crypt, 'MacBdENC', @cmac OUT, @bd

    PRINT @cmac
    -- Output should be: 51f0bebf7e3b9d92fc49741779363cfe

    -- Now do the same for a string:
    DECLARE @plainText nvarchar(4000)
    SELECT @plainText = '''Twas brillig, and the slithy toves' + CHAR(10) + 'Did gyre and gimble in the wabe:' + CHAR(10) + 'All mimsy were the borogoves,' + CHAR(10) + 'And the mome raths outgrabe.'
    DECLARE @encTag nvarchar(4000)
    EXEC sp_OAMethod @crypt, 'MacStringENC', @encTag OUT, @plainText

    PRINT @encTag

    -- Output should be: 4fca1fcbd265048d247f99ab57fa3ceb

    EXEC @hr = sp_OADestroy @crypt
    EXEC @hr = sp_OADestroy @bd


END
GO