(SQL Server) RSA Sign Binary Data and Verify (Recover the Original Data)

Demonstrates how to RSA sign binary data and then verify/recover the original data.

Note: This example uses methods introduced in Chilkat v9.5.0.77.

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 requires the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    -- Load an RSA private key for signing.
    DECLARE @privKey int
    -- Use "Chilkat_9_5_0.PrivateKey" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.PrivateKey', @privKey OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @success int
    EXEC sp_OAMethod @privKey, 'LoadEncryptedPemFile', @success OUT, 'qa_data/pem/rsa_passwd.pem', 'passwd'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @privKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END

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

    EXEC sp_OAMethod @rsa, 'ImportPrivateKeyObj', @success OUT, @privKey

    -- We have some binary data (in hex) to sign
    DECLARE @originalData nvarchar(4000)
    SELECT @originalData = '0102030405060708090A'
    DECLARE @bd int
    -- Use "Chilkat_9_5_0.BinData" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.BinData', @bd OUT

    EXEC sp_OAMethod @bd, 'AppendEncoded', @success OUT, @originalData, 'hex'

    -- If successful, the contents of bd are replaced with the RSA signature.
    EXEC sp_OAMethod @rsa, 'OpenSslSignBd', @success OUT, @bd
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @bd
        RETURN
      END

    -- Show the RSA signature in base64
    EXEC sp_OAMethod @bd, 'GetEncoded', @sTmp0 OUT, 'base64'
    PRINT @sTmp0

    -- ------------------------------------------
    -- Get the public key from the private key
    DECLARE @pubKey int
    EXEC sp_OAMethod @privKey, 'GetPublicKey', @pubKey OUT

    -- Verify the signature and extract the original data.
    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, 'ImportPublicKeyObj', @success OUT, @pubKey

    DECLARE @bVerified int
    EXEC sp_OAMethod @rsa2, 'OpenSslVerifyBd', @bVerified OUT, @bd

    PRINT 'signature verified: ' + @bVerified

    -- Show the original data:

    EXEC sp_OAMethod @bd, 'GetEncoded', @sTmp0 OUT, 'hex'
    PRINT 'original data: ' + @sTmp0

    EXEC @hr = sp_OADestroy @pubKey


    EXEC @hr = sp_OADestroy @privKey
    EXEC @hr = sp_OADestroy @rsa
    EXEC @hr = sp_OADestroy @bd
    EXEC @hr = sp_OADestroy @rsa2


END
GO