ARC4 Encryption (ARCFOUR)

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

Download Chilkat Crypt ActiveX

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

    DECLARE @success int

    EXEC sp_OAMethod @crypt, 'UnlockComponent', @success OUT, 'Anything for 30-day trial'
    IF @success <> 1
      BEGIN
        PRINT 'Crypt component unlock failed'
        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
END
GO