SQL Server

CMS Sign Hash

Demonstrates how to use the SignHashENC method to sign a pre-computed hash. This method creates a CMS signature (PKCS7 detached signature).

This example requires Chilkat v9.5.0.90 or later.

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 @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    -- This example requires 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

    -- Create the hash to be signed...
    EXEC sp_OASetProperty @crypt, 'HashAlgorithm', 'sha256'
    EXEC sp_OASetProperty @crypt, 'EncodingMode', 'base64'
    EXEC sp_OASetProperty @crypt, 'Charset', 'utf-8'
    -- Create the SHA256 hash of a string using the utf-8 byte representation.
    -- Return the hash as base64.
    DECLARE @base64Hash nvarchar(4000)
    EXEC sp_OAMethod @crypt, 'HashStringENC', @base64Hash OUT, 'This is the string to be hashed'

    -- Load a certificate for signing.
    DECLARE @cert int
    EXEC @hr = sp_OACreate 'Chilkat.Cert', @cert OUT

    EXEC sp_OAMethod @cert, 'LoadPfxFile', @success OUT, 'qa_data/pfx/cert_test123.pfx', 'test123'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @cert, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @crypt
        EXEC @hr = sp_OADestroy @cert
        RETURN
      END
    EXEC sp_OAMethod @crypt, 'SetSigningCert', @success OUT, @cert

    -- Sign the hash to create a base64 CMS signature (which does not contain the original data).
    -- We can get the signature in a single line of base64 by specifying "base64", or 
    -- we can get multi-line base64 by specifying "base64_mime".
    EXEC sp_OASetProperty @crypt, 'EncodingMode', 'base64_mime'
    DECLARE @base64CmsSig nvarchar(4000)
    EXEC sp_OAMethod @crypt, 'SignHashENC', @base64CmsSig OUT, @base64Hash, 'sha256', 'base64'
    EXEC sp_OAGetProperty @crypt, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 0
      BEGIN
        EXEC sp_OAGetProperty @crypt, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @crypt
        EXEC @hr = sp_OADestroy @cert
        RETURN
      END

    -- Note: In the above call to SignHashENC, the encoding of the returned CMS signature is specified by the EncodingMode property.
    -- However, the encoding of the passed-in hash is indicated by the 3rd argument.


    PRINT 'CMS Signature: ' + @base64CmsSig

    EXEC @hr = sp_OADestroy @crypt
    EXEC @hr = sp_OADestroy @cert


END
GO