hcipher.java~

文件加密解密程序。内含公开暗号（RAS）加解密工具

/*
 * HCipher.java
 *
 * Created on 2003?月19日, 下?:39
 */

package HUtil.HCipher;

/**
 *
 * @author  H
 */
public class HCipher {
    
    public static final int MODE1 = 1;
    public static final int MODE2 = 2;
    private int mode;
    public final String Version = "2.01";
    
    /** Creates a new instance of HCipher */
    public HCipher(int md) {
        mode = md;
    }
    
    /** Creates a new instance of HCipher */
    public HCipher() {
        mode = MODE2;
    }
    
    private String createPassword(String pswd) throws Exception{
        String re;
        if (mode==this.MODE1){
            int password = Math.abs(pswd.hashCode());
            re = password + "";
        //}else if(mode==MODE2){
        }else{
            byte[] temp = pswd.getBytes();
            StringBuffer sb = new StringBuffer();
            for(int i=0;i<temp.length;i++){
                sb.append(temp[i]+"");
            }
            re = sb.toString();
        }
        return re;
    }
    
    public byte[] cipher(byte[] input, String pswd, String operation_type) throws Exception{
        pswd = this.createPassword(pswd);
        int count = pswd.length();
        int[] s_pswd = new int[count];
        int loopcnt = input.length;
        for(int i=0;i<count;i++){
            s_pswd[i] = Integer.valueOf(pswd.substring(i,i+1)).intValue();
        }
        int pswd_count = 0;
        for (int i=0;i<loopcnt;i++){
            input[i] = (byte)cipher((int)input[i], s_pswd[pswd_count], operation_type);
            pswd_count ++;
            if (pswd_count>=count){
                pswd_count = 0;
            }
        }
        return input;
    }
    
    public int cipher(int input, int password, String operation_type){
        int output_resource;
        if (operation_type.equals("E")){
            output_resource = input - password;
        }else{
            output_resource = input + password;
        }
        return output_resource;
    }
    
}