(SQL Server) Streaming Encryption

Encrypt and decrypt using a stream.

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
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- 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

    -- Setup encryption using the chacha20 algorithm...
    EXEC sp_OASetProperty @crypt, 'CryptAlgorithm', 'chacha20'
    EXEC sp_OASetProperty @crypt, 'KeyLength', 256
    EXEC sp_OASetProperty @crypt, 'EncodingMode', 'hex'
    DECLARE @ivHex nvarchar(4000)
    SELECT @ivHex = '000000000000000000000002'
    EXEC sp_OAMethod @crypt, 'SetEncodedIV', NULL, @ivHex, 'hex'
    EXEC sp_OASetProperty @crypt, 'InitialCount', 42
    DECLARE @keyHex nvarchar(4000)
    SELECT @keyHex = '1c9240a5eb55d38af333888604f6b5f0473917c1402b80099dca5cbc207075c0'
    EXEC sp_OAMethod @crypt, 'SetEncodedKey', NULL, @keyHex, 'hex'

    DECLARE @plainText nvarchar(4000)
    SELECT @plainText = 'The quick brown fox jumped over the lazy dog.' + CHAR(13) + CHAR(10)

    DECLARE @stream int
    -- Use "Chilkat_9_5_0.Stream" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Stream', @stream OUT

    -- We'll save the encrypted output in eStrings to demonstrate streaming decryption next.
    DECLARE @eStrings int
    -- Use "Chilkat_9_5_0.StringArray" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.StringArray', @eStrings OUT

    -- Start a background task that will encrypt a stream.
    DECLARE @task int
    EXEC sp_OAMethod @crypt, 'EncryptStreamAsync', @task OUT, @stream
    DECLARE @success int
    EXEC sp_OAMethod @task, 'Run', @success OUT

    -- Write plainText to the stream, and read chacha20 encrypted text..
    DECLARE @cipherText nvarchar(4000)

    DECLARE @i int

    SELECT @i = 1
    WHILE @i <= 10
      BEGIN
        -- Note: An encryption algorithm's block size will cause buffering,
        -- and therefore not every loop iteration will produce output.
        EXEC sp_OAMethod @stream, 'WriteString', @success OUT, @plainText
        EXEC sp_OAGetProperty @stream, 'DataAvailable', @iTmp0 OUT
        IF @iTmp0 = 1
          BEGIN
            EXEC sp_OAMethod @stream, 'ReadBytesENC', @cipherText OUT, 'hex'

            PRINT @cipherText
            EXEC sp_OAMethod @eStrings, 'Append', @success OUT, @cipherText
          END
        SELECT @i = @i + 1
      END

    -- Tell the background task that the stream has ended.
    EXEC sp_OAMethod @stream, 'WriteClose', @success OUT

    -- Let's make sure the background task finished.
    -- It should already be the case that the task is finished.
    EXEC sp_OAGetProperty @task, 'Finished', @iTmp0 OUT
    WHILE (@iTmp0 <> 1)
      BEGIN
        EXEC sp_OAMethod @task, 'SleepMs', NULL, 20
      END

    -- Get any remaining data available from the stream.
    EXEC sp_OAGetProperty @stream, 'DataAvailable', @iTmp0 OUT
    IF @iTmp0 = 1
      BEGIN
        EXEC sp_OAMethod @stream, 'ReadBytesENC', @cipherText OUT, 'hex'

        PRINT @cipherText
        EXEC sp_OAMethod @eStrings, 'Append', @success OUT, @cipherText
      END

    EXEC sp_OAGetProperty @task, 'TaskSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN

        PRINT 'async encryption failed:'
        EXEC sp_OAGetProperty @task, 'ResultErrorText', @sTmp0 OUT
        PRINT @sTmp0
        SELECT @success = 0
      END

    EXEC @hr = sp_OADestroy @task


    PRINT '-- encrypt finished --'

    -- Now decrypt to return the original.

    -- Reset the stream object so it can be used again.
    EXEC sp_OAMethod @stream, 'Reset', NULL

    -- Start a background task that will decrypt a stream.
    EXEC sp_OAMethod @crypt, 'DecryptStreamAsync', @task OUT, @stream
    EXEC sp_OAMethod @task, 'Run', @success OUT

    DECLARE @n int
    EXEC sp_OAGetProperty @eStrings, 'Count', @n OUT
    SELECT @i = 0
    WHILE @i <= @n - 1
      BEGIN
        EXEC sp_OAMethod @eStrings, 'GetString', @sTmp0 OUT, @i
        EXEC sp_OAMethod @stream, 'WriteBytesENC', @success OUT, @sTmp0, 'hex'
        EXEC sp_OAGetProperty @stream, 'DataAvailable', @iTmp0 OUT
        IF @iTmp0 = 1
          BEGIN
            EXEC sp_OAMethod @stream, 'ReadString', @plainText OUT

            PRINT @plainText
          END
        SELECT @i = @i + 1
      END

    -- Tell the background task that the stream has ended.
    EXEC sp_OAMethod @stream, 'WriteClose', @success OUT

    -- Let's make sure the background task finished.
    -- It should already be the case that the task is finished.
    EXEC sp_OAGetProperty @task, 'Finished', @iTmp0 OUT
    WHILE (@iTmp0 <> 1)
      BEGIN
        EXEC sp_OAMethod @task, 'SleepMs', NULL, 20
      END

    -- Get any remaining data available from the stream.
    EXEC sp_OAGetProperty @stream, 'DataAvailable', @iTmp0 OUT
    IF @iTmp0 = 1
      BEGIN
        EXEC sp_OAMethod @stream, 'ReadString', @plainText OUT

        PRINT @plainText
      END

    EXEC sp_OAGetProperty @task, 'TaskSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN

        PRINT 'async decryption failed:'
        EXEC sp_OAGetProperty @task, 'ResultErrorText', @sTmp0 OUT
        PRINT @sTmp0
        SELECT @success = 0
      END

    EXEC @hr = sp_OADestroy @task


    PRINT '-- decrypt finished --'

    EXEC @hr = sp_OADestroy @crypt
    EXEC @hr = sp_OADestroy @stream
    EXEC @hr = sp_OADestroy @eStrings


END
GO