SQL Server

ECDSA Sign and Verify Data using Different Hash Algorithms

See more ECC Examples

Demonstrates how to create ECDSA signatures on data using different hash algorithms.

Note: This example requires Chilkat v9.5.0.85 or greater because the SignBd and VerifyBd methods were added in v9.5.0.85.

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.

    -- First load an ECDSA private key to be used for signing.
    DECLARE @privKey int
    EXEC @hr = sp_OACreate 'Chilkat.PrivateKey', @privKey OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    EXEC sp_OAMethod @privKey, 'LoadEncryptedPemFile', @success OUT, 'qa_data/ecc/secp256r1-key-pkcs8-secret.pem', 'secret'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @privKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END

    -- Load some data to be signed.
    DECLARE @bd int
    EXEC @hr = sp_OACreate 'Chilkat.BinData', @bd OUT

    EXEC sp_OAMethod @bd, 'LoadFile', @success OUT, 'qa_data/hamlet.xml'
    IF @success = 0
      BEGIN

        PRINT 'Failed to load file to be hashed.'
        EXEC @hr = sp_OADestroy @privKey
        EXEC @hr = sp_OADestroy @bd
        RETURN
      END

    DECLARE @ecdsa int
    EXEC @hr = sp_OACreate 'Chilkat.Ecc', @ecdsa OUT

    DECLARE @prng int
    EXEC @hr = sp_OACreate 'Chilkat.Prng', @prng OUT

    -- Sign the sha256 hash of the data.  Return the ECDSA signature in the base64 encoding.

    PRINT 'ECDSA signing the sha256 hash of the data...'
    DECLARE @sig nvarchar(4000)
    EXEC sp_OAMethod @ecdsa, 'SignBd', @sig OUT, @bd, 'sha256', 'base64', @privKey, @prng

    PRINT 'sig = ' + @sig

    -- Verify the signature against the original data.
    -- (We must use the same hash algorithm that was used when signing.)

    -- Load the public key that corresponds to the private key used for signing.
    DECLARE @pubKey int
    EXEC @hr = sp_OACreate 'Chilkat.PublicKey', @pubKey OUT

    EXEC sp_OAMethod @pubKey, 'LoadFromFile', @success OUT, 'qa_data/ecc/secp256r1-pub.pem'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @pubKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        EXEC @hr = sp_OADestroy @bd
        EXEC @hr = sp_OADestroy @ecdsa
        EXEC @hr = sp_OADestroy @prng
        EXEC @hr = sp_OADestroy @pubKey
        RETURN
      END

    DECLARE @ecc2 int
    EXEC @hr = sp_OACreate 'Chilkat.Ecc', @ecc2 OUT

    DECLARE @result int
    EXEC sp_OAMethod @ecc2, 'VerifyBd', @result OUT, @bd, 'sha256', @sig, 'base64', @pubKey
    IF @result <> 1
      BEGIN
        EXEC sp_OAGetProperty @ecc2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        EXEC @hr = sp_OADestroy @bd
        EXEC @hr = sp_OADestroy @ecdsa
        EXEC @hr = sp_OADestroy @prng
        EXEC @hr = sp_OADestroy @pubKey
        EXEC @hr = sp_OADestroy @ecc2
        RETURN
      END


    PRINT 'Verified!'

    -- ----------------------------------------------------------------------------------------
    -- Let's do the same thing, but with sha384 hashing...


    PRINT '--------------------------------------------'

    PRINT 'ECDSA signing the sha384 hash of the data...'

    EXEC sp_OAMethod @ecdsa, 'SignBd', @sig OUT, @bd, 'sha384', 'base64', @privKey, @prng

    PRINT 'sig = ' + @sig

    EXEC sp_OAMethod @ecc2, 'VerifyBd', @result OUT, @bd, 'sha384', @sig, 'base64', @pubKey
    IF @result <> 1
      BEGIN
        EXEC sp_OAGetProperty @ecc2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        EXEC @hr = sp_OADestroy @bd
        EXEC @hr = sp_OADestroy @ecdsa
        EXEC @hr = sp_OADestroy @prng
        EXEC @hr = sp_OADestroy @pubKey
        EXEC @hr = sp_OADestroy @ecc2
        RETURN
      END


    PRINT 'Verified!'

    EXEC @hr = sp_OADestroy @privKey
    EXEC @hr = sp_OADestroy @bd
    EXEC @hr = sp_OADestroy @ecdsa
    EXEC @hr = sp_OADestroy @prng
    EXEC @hr = sp_OADestroy @pubKey
    EXEC @hr = sp_OADestroy @ecc2


END
GO