/*

* Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

* signatureverfier.h

*

*/

/**

 @file

 @released

 @internalTechnology

*/

#ifndef __SIGNATUREVERFIER_H__

#define __SIGNATUREVERFIER_H__

#include <e32base.h>

#include <signed.h>

class CMessageDigest;

class CASN1EncSequence;

namespace Swi

{

  /**

   * This Security Manager helper class takes care of verifying signatures.

   */

  class CSignatureVerifier : public CBase

  {

  public : 

    /**

     * Creates a new signature verifier

     *

     * @return A new signature verifier

     */

    static CSignatureVerifier* NewL();

	/**

     * Creates a new signature verifier and leaves it on the cleanup stack

     *

     * @return A new signature verifier

	 */

    static CSignatureVerifier* NewLC();

    ~CSignatureVerifier();    

  public : // Business methods

	/**

	 * This is the main service provided by this class, it verifies a signature.

	 *

	 * @param aSchemeOid       The OID of the signature scheme used

	 * @param aPublicKey       The public key used to verity the signature

	 * @param aControllerData  The signed data

	 * @param aSignatureData   The actual signature data

	 *

	 * @return ETrue if the signature can be verified, EFalse otherwise

	 */	

	TBool VerifySignatureL(const TDesC& aSchemeOid, 

						   const CSubjectPublicKeyInfo& aPublicKey, 

						   const TPtrC8& aControllerData,

						   const TDesC8& aSignatureData);

  protected : // Helpers

	/**

	 * An internal method which given a signature OID converts it 

	 * to its corresponding internal TAlgorithmId code

	 * 

	 * @param aSchemeOid The OID we wish to convert

	 * 

	 * @return The TAlgorithmId identifier corresponding to the given OID

	 */

	TAlgorithmId OidToIdL(const TDesC& aSchemeOid);

	/**

	 * Helper method which builds an ASN.1 Digest info structure for

	 * RSA signatures. RSA signatures work on digest info structure rather 

	 * than on raw digest as DSA does. After the method call the ASN.1 Sequence

	 * returned is left on the cleanup stack.

	 *

	 * @param aDigest    The actual message digest

	 * @param aPublicKey The RSA public key

	 * @param aDigestId  The digest identifier

	 *

	 * @return An ASN.1 structure containing the digest info needed to either

	 *         verify or sign some data

	 */  

	CASN1EncSequence* DigestInfoLC(const TDesC8& aDigest, const CRSAPublicKey& aPublicKey, 

	                               TAlgorithmId aDigestId);	

	/**

	 * This internal method creates an appropriate CMessageDigest given a certain

	 * digest OID

	 *

	 * @param aSchemeOid The OID of the digest scheme we are interested in

	 *

	 * @return An instance of CMessageDigest corresponding to the given OID

	 */	                           

	CMessageDigest* CreateDigestL(const TDesC& aSchemeOid);

  private : // Life cycle methods

    CSignatureVerifier();

    void ConstructL();      

  private : 

  };

} // namespace Swi

#endif // __SIGNATUREVERFIER_H__