(SQL Server) RSA Sign with PKCS8 Encrypted Key

Demonstrates how to load a private key from an encrypted PKCS8 file and create an RSA digital signature (and then verify it).

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

    -- Load the private key from an RSA PEM file:
    DECLARE @success int
    EXEC sp_OAMethod @pkey, 'LoadPkcs8EncryptedFile', @success OUT, 'raul_privateKey.key', 'a0123456789'

    DECLARE @pkeyXml nvarchar(4000)

    -- Get the private key in XML format:
    EXEC sp_OAMethod @pkey, 'GetXml', @pkeyXml OUT

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

    -- Import the private key into the RSA component:
    EXEC sp_OAMethod @rsa, 'ImportPrivateKey', @success OUT, @pkeyXml
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pkey
        EXEC @hr = sp_OADestroy @rsa
        RETURN
      END

    -- This example will sign a string, and receive the signature
    -- in a hex-encoded string.  Therefore, set the encoding mode
    -- to "hex":
    EXEC sp_OASetProperty @rsa, 'EncodingMode', 'hex'

    DECLARE @strData nvarchar(4000)
    SELECT @strData = 'This is the string to be signed.'

    -- Sign the string using the sha-1 hash algorithm.
    -- Other valid choices are "md2" and "md5".
    DECLARE @hexSig nvarchar(4000)
    EXEC sp_OAMethod @rsa, 'SignStringENC', @hexSig OUT, @strData, 'sha-1'


    PRINT @hexSig

    -- Now verify with the public key.
    -- This example shows how to use the public key from 
    -- a digital certificate (.cer file)
    DECLARE @cert int
    -- Use "Chilkat_9_5_0.Cert" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Cert', @cert OUT

    EXEC sp_OAMethod @cert, 'LoadFromFile', @success OUT, 'raul_publicKey.cer'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @cert, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pkey
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @cert
        RETURN
      END

    DECLARE @pubKey int

    EXEC sp_OAMethod @cert, 'ExportPublicKey', @pubKey OUT

    DECLARE @pubKeyXml nvarchar(4000)

    -- Get the private key in XML format:
    EXEC sp_OAMethod @pubKey, 'GetXml', @pubKeyXml OUT

    DECLARE @rsa2 int
    -- Use "Chilkat_9_5_0.Rsa" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Rsa', @rsa2 OUT

    EXEC sp_OAMethod @rsa2, 'ImportPublicKey', @success OUT, @pubKeyXml
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rsa2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pkey
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @cert
        EXEC @hr = sp_OADestroy @rsa2
        RETURN
      END

    -- Verify the signature against the original data:
    EXEC sp_OASetProperty @rsa2, 'EncodingMode', 'hex'
    EXEC sp_OAMethod @rsa2, 'VerifyStringENC', @success OUT, @strData, 'sha-1', @hexSig
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rsa2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pkey
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @cert
        EXEC @hr = sp_OADestroy @rsa2
        RETURN
      END

    PRINT 'Signature verified!'

    -- Verify with incorrect data:
    EXEC sp_OAMethod @rsa2, 'VerifyStringENC', @success OUT, 'something else', 'sha-1', @hexSig
    IF @success <> 1
      BEGIN

        PRINT 'Signature not verified! (which was expected in this case)'
      END
    ELSE
      BEGIN

        PRINT 'Hmmm... that''s not right...'
      END

    EXEC @hr = sp_OADestroy @pubKey


    EXEC @hr = sp_OADestroy @pkey
    EXEC @hr = sp_OADestroy @rsa
    EXEC @hr = sp_OADestroy @cert
    EXEC @hr = sp_OADestroy @rsa2


END
GO