SQL Server

RSA Signature/Verify with .key and .cer

See more RSA Examples

Demonstrates how to use a .key file (private key) and digital certificate (.cer, public key) to create and verify an RSA signature. 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
    -- 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 assumes the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @privKey int
    EXEC @hr = sp_OACreate 'Chilkat.PrivateKey', @privKey OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- Load the private key from an RSA .key file:
    EXEC sp_OAMethod @privKey, 'LoadPemFile', @success OUT, 'privateKey.key'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @privKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END

    DECLARE @rsa int
    EXEC @hr = sp_OACreate 'Chilkat.Rsa', @rsa OUT

    -- Import the private key into the RSA component:
    EXEC sp_OAMethod @rsa, 'UsePrivateKey', @success OUT, @privKey
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        EXEC @hr = sp_OADestroy @rsa
        RETURN
      END

    -- Create the signature as a hex string:
    EXEC sp_OASetProperty @rsa, 'EncodingMode', 'hex'

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

    -- Sign the string using the sha256 hash algorithm.
    -- Other valid choices are "md2", "sha1", "sha384",
    -- "sha512", and "md5".
    DECLARE @hexSig nvarchar(4000)
    EXEC sp_OAMethod @rsa, 'SignStringENC', @hexSig OUT, @strData, 'sha256'


    PRINT @hexSig

    -- Load a digital certificate from a .cer file:
    DECLARE @cert int
    EXEC @hr = sp_OACreate 'Chilkat.Cert', @cert OUT

    EXEC sp_OAMethod @cert, 'LoadFromFile', @success OUT, 'myCert.cer'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @cert, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @cert
        RETURN
      END

    DECLARE @pubKey int
    EXEC @hr = sp_OACreate 'Chilkat.PublicKey', @pubKey OUT

    EXEC sp_OAMethod @cert, 'GetPublicKey', @success OUT, @pubKey

    -- Now verify using a new instance of the RSA object:
    DECLARE @rsa2 int
    EXEC @hr = sp_OACreate 'Chilkat.Rsa', @rsa2 OUT

    -- Import the public key into the RSA object:
    EXEC sp_OAMethod @rsa2, 'UsePublicKey', @success OUT, @pubKey
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @rsa2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @cert
        EXEC @hr = sp_OADestroy @pubKey
        EXEC @hr = sp_OADestroy @rsa2
        RETURN
      END

    -- The signature is a hex string, so make sure the EncodingMode is correct:
    EXEC sp_OASetProperty @rsa2, 'EncodingMode', 'hex'

    -- Verify the signature:
    EXEC sp_OAMethod @rsa2, 'VerifyStringENC', @success OUT, @strData, 'sha256', @hexSig
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @rsa2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @cert
        EXEC @hr = sp_OADestroy @pubKey
        EXEC @hr = sp_OADestroy @rsa2
        RETURN
      END


    PRINT 'Success.'

    EXEC @hr = sp_OADestroy @privKey
    EXEC @hr = sp_OADestroy @rsa
    EXEC @hr = sp_OADestroy @cert
    EXEC @hr = sp_OADestroy @pubKey
    EXEC @hr = sp_OADestroy @rsa2


END
GO