/*
   Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; see the file COPYING. If not, write to the
   Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
   MA  02110-1301  USA.
*/

/* dsa.hpp provides Digitial Signautre Algorithm see FIPS 186-2
*/

#ifndef TAO_CRYPT_DSA_HPP
#define TAO_CRYPT_DSA_HPP

#include "integer.hpp"


namespace TaoCrypt {

class Source;


class DSA_PublicKey {
protected:
    Integer p_;
    Integer q_;
    Integer g_;
    Integer y_;
public:
    DSA_PublicKey() {}
    explicit DSA_PublicKey(Source&);

    void Initialize(Source&);
    void Initialize(const Integer& p, const Integer& q, const Integer& g,
                    const Integer& y);
    
    const Integer& GetModulus() const;
    const Integer& GetSubGroupOrder() const;
    const Integer& GetSubGroupGenerator() const;
    const Integer& GetPublicPart() const;

    void SetModulus(const Integer&);
    void SetSubGroupOrder(const Integer&);
    void SetSubGroupGenerator(const Integer&);
    void SetPublicPart(const Integer&);

    word32 SignatureLength() const;
 
    DSA_PublicKey(const DSA_PublicKey&);
    DSA_PublicKey& operator=(const DSA_PublicKey&);

    void Swap(DSA_PublicKey& other);
};



class DSA_PrivateKey : public DSA_PublicKey {
    Integer x_;
public:
    DSA_PrivateKey() {}
    explicit DSA_PrivateKey(Source&);

    void Initialize(Source&);
    void Initialize(const Integer& p, const Integer& q, const Integer& g,
                    const Integer& y, const Integer& x);
    
    const Integer& GetPrivatePart() const;

    void SetPrivatePart(const Integer&);
private:
    DSA_PrivateKey(const DSA_PrivateKey&);            // hide copy
    DSA_PrivateKey& operator=(const DSA_PrivateKey&); // and assign
};



class DSA_Signer {
    const DSA_PrivateKey& key_;
    Integer               r_;
    Integer               s_;
public:
    explicit DSA_Signer(const DSA_PrivateKey&);

    word32 Sign(const byte* sha_digest, byte* sig, RandomNumberGenerator&);

    const Integer& GetR() const;
    const Integer& GetS() const;
private:
    DSA_Signer(const DSA_Signer&);      // hide copy
    DSA_Signer& operator=(DSA_Signer&); // and assign
};


class DSA_Verifier {
    const DSA_PublicKey& key_;
    Integer              r_;
    Integer              s_;
public:
    explicit DSA_Verifier(const DSA_PublicKey&);

    bool Verify(const byte* sha_digest, const byte* sig);

    const Integer& GetR() const;
    const Integer& GetS() const;
private:
    DSA_Verifier(const DSA_Verifier&);              // hide copy
    DSA_Verifier& operator=(const DSA_Verifier&);   // and assign
};





} // namespace

#endif // TAO_CRYPT_DSA_HPP
