(SQL Server) Duplicate openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

Demonstrates how to duplicate this OpenSSL command:

openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

1. Creates a SHA256 digest of the contents of the input file.
2. Verifies the SHA256 digest using the public key.

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.

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

    -- Load the public key from an PEM file:
    DECLARE @success int
    EXEC sp_OAMethod @pubKey, 'LoadFromFile', @success OUT, 'pubKey.pem'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @pubKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pubKey
        RETURN
      END

    -- Load the data of the original file that was signed.
    DECLARE @bdFileData int
    -- Use "Chilkat_9_5_0.BinData" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.BinData', @bdFileData OUT

    EXEC sp_OAMethod @bdFileData, 'LoadFile', @success OUT, 'in.dat'

    -- Load the signature.
    DECLARE @bdSig int
    -- Use "Chilkat_9_5_0.BinData" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.BinData', @bdSig OUT

    EXEC sp_OAMethod @bdSig, 'LoadFile', @success OUT, 'signature.sig'

    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 public key into the RSA component:
    EXEC sp_OAMethod @rsa, 'ImportPublicKeyObj', @success OUT, @pubKey
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @pubKey
        EXEC @hr = sp_OADestroy @bdFileData
        EXEC @hr = sp_OADestroy @bdSig
        EXEC @hr = sp_OADestroy @rsa
        RETURN
      END

    -- OpenSSL uses big-endian.
    EXEC sp_OASetProperty @rsa, 'LittleEndian', 0

    EXEC sp_OAMethod @rsa, 'VerifyBd', @success OUT, @bdFileData, 'sha256', @bdSig
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0

        PRINT 'The signature was invalid.'
        EXEC @hr = sp_OADestroy @pubKey
        EXEC @hr = sp_OADestroy @bdFileData
        EXEC @hr = sp_OADestroy @bdSig
        EXEC @hr = sp_OADestroy @rsa
        RETURN
      END


    PRINT 'The signature was verified.'

    EXEC @hr = sp_OADestroy @pubKey
    EXEC @hr = sp_OADestroy @bdFileData
    EXEC @hr = sp_OADestroy @bdSig
    EXEC @hr = sp_OADestroy @rsa


END
GO