(SQL Server) ARC4 Encryption (ARCFOUR)

ARC4 (ARCFOUR) encryption. The Chilkat encryption component supports the ARC4 streaming encryption algorithm.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    -- This example assumes the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @crypt int
    -- Use "Chilkat_9_5_0.Crypt2" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Crypt2', @crypt OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- Set the encryption algorithm = "arc4"	
    EXEC sp_OASetProperty @crypt, 'CryptAlgorithm', 'arc4'

    -- KeyLength may range from 1 byte to 256 bytes.
    -- (i.e. 8 bits to 2048 bits)
    -- ARC4 key sizes are typically in the range of 
    -- 40 to 128 bits.
    -- The KeyLength property is specified in bits:
    EXEC sp_OASetProperty @crypt, 'KeyLength', 128

    -- Note: The PaddingScheme and CipherMode properties
    -- do not apply w/ ARC4.  ARC4 does not encrypt in blocks --
    -- it is a streaming encryption algorithm. The number of output bytes
    -- is exactly equal to the number of input bytes.

    -- EncodingMode specifies the encoding of the output for
    -- encryption, and the input for decryption.
    -- It may be "hex", "url", "base64", or "quoted-printable".
    EXEC sp_OASetProperty @crypt, 'EncodingMode', 'hex'

    -- Note: ARC4 does not utilize initialization vectors.  IV's only
    -- apply to block encryption algorithms.  

    -- The secret key must equal the size of the key.
    -- For 128-bit encryption, the binary secret key is 16 bytes.
    DECLARE @keyHex nvarchar(4000)
    SELECT @keyHex = '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F'
    EXEC sp_OAMethod @crypt, 'SetEncodedKey', NULL, @keyHex, 'hex'

    -- Encrypt a string...
    -- The output length is exactly equal to the input.  In this
    -- example, the input string is 44 chars (ANSI bytes) so the
    -- output is 44 bytes -- and when hex encoded results in an
    -- 88-char string (2 chars per byte for the hex encoding).
    DECLARE @encStr nvarchar(4000)
    EXEC sp_OAMethod @crypt, 'EncryptStringENC', @encStr OUT, 'The quick brown fox jumps over the lazy dog.'

    PRINT @encStr

    -- Now decrypt:
    DECLARE @decStr nvarchar(4000)
    EXEC sp_OAMethod @crypt, 'DecryptStringENC', @decStr OUT, @encStr

    PRINT @decStr

    EXEC @hr = sp_OADestroy @crypt


END
GO