(SQL Server) Extract PKCS7 Signature Digest

Demonstrates how to extract a signature digest from a PKCS7 signature.

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 requires the Chilkat Crypt API to have been previously unlocked.
    -- See Unlock Chilkat Crypt 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

    DECLARE @p7mFile nvarchar(4000)
    SELECT @p7mFile = 'qa_data/p7m/test.pdf.p7m'
    DECLARE @outPath nvarchar(4000)
    SELECT @outPath = 'qa_output/test.pdf'

    -- First let's see if this .p7m signature can be verified, and the original file extracted.
    DECLARE @verified int
    EXEC sp_OAMethod @crypt, 'VerifyP7M', @verified OUT, @p7mFile, @outPath
    IF @verified <> 1
      BEGIN
        EXEC sp_OAGetProperty @crypt, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @crypt
        RETURN
      END

    -- How many signers?
    -- (The NumSignerCerts property is set whenever a signature is verified.)

    EXEC sp_OAGetProperty @crypt, 'NumSignerCerts', @iTmp0 OUT
    PRINT 'Num Signers: ' + @iTmp0

    -- Load the .p7m into memory...
    DECLARE @pkcs7Data int
    -- Use "Chilkat_9_5_0.BinData" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.BinData', @pkcs7Data OUT

    DECLARE @success int
    EXEC sp_OAMethod @pkcs7Data, 'LoadFile', @success OUT, @p7mFile

    -- Check to see if this .p7m contains the binary bytes, or if it's
    -- already base64 encoded.  Get the 1st two bytes.  If the first two 
    -- bytes are the us-ascii values "MI", then we have base64.
    DECLARE @sbBase64 int
    -- Use "Chilkat_9_5_0.StringBuilder" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.StringBuilder', @sbBase64 OUT

    DECLARE @hexStr nvarchar(4000)
    EXEC sp_OAMethod @pkcs7Data, 'GetEncodedChunk', @hexStr OUT, 0, 2, 'hex'
    EXEC sp_OAMethod @sbBase64, 'Append', @success OUT, @hexStr

    DECLARE @bHaveBase64 int
    SELECT @bHaveBase64 = 0
    EXEC sp_OAMethod @sbBase64, 'ContentsEqual', @iTmp0 OUT, '4D49', 1
    IF @iTmp0 = 1
      BEGIN
        SELECT @bHaveBase64 = 1
        EXEC sp_OAMethod @sbBase64, 'Clear', NULL
        EXEC sp_OAMethod @sbBase64, 'AppendBd', @success OUT, @pkcs7Data, 'utf-8', 0, 0
      END

    -- Get each signer's signature digest.
    EXEC sp_OASetProperty @crypt, 'EncodingMode', 'base64'
    DECLARE @i int
    SELECT @i = 0
    DECLARE @digest nvarchar(4000)

    EXEC sp_OAGetProperty @crypt, 'NumSignerCerts', @iTmp0 OUT
    WHILE @i < @iTmp0
      BEGIN
        IF @bHaveBase64
          BEGIN
            EXEC sp_OAMethod @sbBase64, 'GetAsString', @sTmp0 OUT
            EXEC sp_OAMethod @crypt, 'Pkcs7ExtractDigest', @digest OUT, @i, @sTmp0
          END
        ELSE
          BEGIN
            EXEC sp_OAMethod @pkcs7Data, 'GetEncoded', @sTmp0 OUT, 'base64'
            EXEC sp_OAMethod @crypt, 'Pkcs7ExtractDigest', @digest OUT, @i, @sTmp0
          END
        EXEC sp_OAGetProperty @crypt, 'LastMethodSuccess', @iTmp0 OUT
        IF @iTmp0 <> 1
          BEGIN
            EXEC sp_OAGetProperty @crypt, 'LastErrorText', @sTmp0 OUT
            PRINT @sTmp0
            EXEC @hr = sp_OADestroy @crypt
            EXEC @hr = sp_OADestroy @pkcs7Data
            EXEC @hr = sp_OADestroy @sbBase64
            RETURN
          END


        PRINT 'Signer ' + @i + 1 + ' digest = ' + @digest
        SELECT @i = @i + 1
      END

    EXEC @hr = sp_OADestroy @crypt
    EXEC @hr = sp_OADestroy @pkcs7Data
    EXEC @hr = sp_OADestroy @sbBase64


END
GO