TC.java

/*
*******************************************************************************    
*   BTChip Bitcoin Hardware Wallet Java Card implementation
*   (c) 2013 BTChip - 1BTChip7VfTnrPra5jqci7ejnMguuHogTn
*   
*   This program is free software: you can redistribute it and/or modify
*   it under the terms of the GNU Affero General Public License as
*   published by the Free Software Foundation, either version 3 of the
*   License, or (at your option) any later version.
*
*   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 Affero General Public License for more details.
*
*   You should have received a copy of the GNU Affero General Public License
*   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*******************************************************************************   
*/    

package com.btchip.applet.poc;

import javacard.framework.JCSystem;
import javacard.framework.Util;

/**
 * Storage of transaction context
 * @author BTChip
 *
 */
public class TC {
    
    public static void init() {
        ctx = JCSystem.makeTransientByteArray(TX_CONTEXT_SIZE, JCSystem.CLEAR_ON_DESELECT);
        ctxP = new byte[P_TX_CONTEXT_SIZE];
    }
    
    public static void clear() {
        Util.arrayFillNonAtomic(ctx, (short)0, (short)ctx.length, (byte)0x00);
        if (ctxP[P_TX_Z_USED] == TRUE) {
            ctxP[P_TX_Z_USED] = FALSE;
        }
    }
    
    protected static final byte SIZEOF_U32 = 4;
    protected static final byte SIZEOF_U8 = 1;
    protected static final byte SIZEOF_AMOUNT = 8;
    protected static final byte SIZEOF_NONCE = 8;
    protected static final byte SIZEOF_SHA256 = 32;
    protected static final byte SIZEOF_RIPEMD = 20;
    protected static final byte SIZEOF_ENCODED_PRIVATEKEY = 40;
    
    protected static final byte TRUE = (byte)0x37;
    protected static final byte FALSE = (byte)0xda;
    
    protected static final short TX_B_HASH_OPTION = (short)0;
    protected static final short TX_B_OPERATION_PARAMETER = (short)(TX_B_HASH_OPTION + SIZEOF_U8);
    protected static final short TX_B_TRUSTED_INPUT_PROCESSED = (short)(TX_B_OPERATION_PARAMETER + SIZEOF_U8);
    protected static final short TX_B_TRUSTED_INPUT_KEYSET = (short)(TX_B_TRUSTED_INPUT_PROCESSED + SIZEOF_U8);
    protected static final short TX_I_TRANSACTION_TARGET_INPUT = (short)(TX_B_TRUSTED_INPUT_KEYSET + SIZEOF_U8);
    protected static final short TX_I_REMAINING_IO = (short)(TX_I_TRANSACTION_TARGET_INPUT + SIZEOF_U32);
    protected static final short TX_I_CURRENT_IO = (short)(TX_I_REMAINING_IO + SIZEOF_U32);
    protected static final short TX_I_SCRIPT_REMAINING = (short)(TX_I_CURRENT_IO + SIZEOF_U32);
    protected static final short TX_B_TRANSACTION_STATE = (short)(TX_I_SCRIPT_REMAINING + SIZEOF_U32);
    protected static final short TX_A_TRANSACTION_AMOUNT = (short)(TX_B_TRANSACTION_STATE + SIZEOF_U8);
    protected static final short TX_A_AUTHORIZATION_HASH = (short)(TX_A_TRANSACTION_AMOUNT + SIZEOF_AMOUNT);
    protected static final short TX_Z_FIRST_SIGNED = (short)(TX_A_AUTHORIZATION_HASH + SIZEOF_SHA256);
    protected static final short TX_Z_HAS_CHANGE = (short)(TX_Z_FIRST_SIGNED + SIZEOF_U8);
    protected static final short TX_Z_IS_P2SH = (short)(TX_Z_HAS_CHANGE + SIZEOF_U8);
    protected static final short TX_Z_IS_RAM = (short)(TX_Z_IS_P2SH + SIZEOF_U8);
    protected static final short TX_A_AUTH_NONCE = (short)(TX_Z_IS_RAM + SIZEOF_U8); // must be a counter
    protected static final short TX_A_AUTH_OUTPUT_ADDRESS = (short)(TX_A_AUTH_NONCE + SIZEOF_NONCE);
    protected static final short TX_A_AUTH_OUTPUT_AMOUNT = (short)(TX_A_AUTH_OUTPUT_ADDRESS + SIZEOF_RIPEMD + 1);
    protected static final short TX_A_AUTH_FEE_AMOUNT = (short)(TX_A_AUTH_OUTPUT_AMOUNT + SIZEOF_AMOUNT);
    protected static final short TX_A_AUTH_CHANGE_AMOUNT = (short)(TX_A_AUTH_FEE_AMOUNT + SIZEOF_AMOUNT);  
    protected static final short TX_A_AUTH_CHANGE_ADDRESS = (short)(TX_A_AUTH_CHANGE_AMOUNT + SIZEOF_AMOUNT);
    protected static final short TX_CONTEXT_SIZE = (short)(TX_A_AUTH_CHANGE_ADDRESS + SIZEOF_RIPEMD + 1);
    protected static final short TX_AUTH_CONTEXT_SIZE = (short)(TX_CONTEXT_SIZE - TX_A_AUTH_NONCE);
    
    protected static final short P_TX_Z_USED = (short)0;
    protected static final short P_TX_A_AUTHORIZATION_HASH = (short)(P_TX_Z_USED + SIZEOF_U8);
    protected static final short P_TX_B_TRANSACTION_STATE = (short)(P_TX_A_AUTHORIZATION_HASH + SIZEOF_SHA256);
    protected static final short P_TX_Z_FIRST_SIGNED = (short)(P_TX_B_TRANSACTION_STATE + SIZEOF_U8);
    protected static final short P_TX_Z_HAS_CHANGE = (short)(P_TX_Z_FIRST_SIGNED + SIZEOF_U8);
    protected static final short P_TX_Z_IS_P2SH = (short)(P_TX_Z_HAS_CHANGE + SIZEOF_U8);
    protected static final short P_TX_A_AUTH_NONCE = (short)(P_TX_Z_IS_P2SH + SIZEOF_U8); // must be a counter
    protected static final short P_TX_A_AUTH_OUTPUT_ADDRESS = (short)(P_TX_A_AUTH_NONCE + SIZEOF_NONCE);
    protected static final short P_TX_A_AUTH_OUTPUT_AMOUNT = (short)(P_TX_A_AUTH_OUTPUT_ADDRESS + SIZEOF_RIPEMD + 1);
    protected static final short P_TX_A_AUTH_FEE_AMOUNT = (short)(P_TX_A_AUTH_OUTPUT_AMOUNT + SIZEOF_AMOUNT);
    protected static final short P_TX_A_AUTH_CHANGE_AMOUNT = (short)(P_TX_A_AUTH_FEE_AMOUNT + SIZEOF_AMOUNT);  
    protected static final short P_TX_A_AUTH_CHANGE_ADDRESS = (short)(P_TX_A_AUTH_CHANGE_AMOUNT + SIZEOF_AMOUNT);
    protected static final short P_TX_CONTEXT_SIZE = (short)(P_TX_A_AUTH_CHANGE_ADDRESS + SIZEOF_RIPEMD + 1);
    protected static final short P_TX_AUTH_CONTEXT_SIZE = (short)(P_TX_CONTEXT_SIZE - P_TX_A_AUTH_NONCE);
        
    protected static byte[] ctx;
    protected static byte[] ctxP;

}