/* -*-mode:java; c-basic-offset:2; indent-tabs-mode:nil -*- */
/*
Copyright (c) 2002,2003,2004,2005,2006 ymnk, JCraft,Inc. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

  1. Redistributions of source code must retain the above copyright notice,
     this list of conditions and the following disclaimer.

  2. Redistributions in binary form must reproduce the above copyright 
     notice, this list of conditions and the following disclaimer in 
     the documentation and/or other materials provided with the distribution.

  3. The names of the authors may not be used to endorse or promote products
     derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

package net.sf.j3d.ext.com.jcraft.jsch;

import java.io.*;

class IdentityFile implements Identity{
  String identity;
  byte[] key;
  byte[] iv;
  private JSch jsch;
  private HASH hash;
  private byte[] encoded_data;

  private Cipher cipher;

  // DSA
  private byte[] P_array;    
  private byte[] Q_array;    
  private byte[] G_array;    
  private byte[] pub_array;    
  private byte[] prv_array;    
 
  // RSA
  private  byte[] n_array;   // modulus
  private  byte[] e_array;   // public exponent
  private  byte[] d_array;   // private exponent
 
//  private String algname="ssh-dss";
  private String algname="ssh-rsa";

  private static final int ERROR=0;
  private static final int RSA=1;
  private static final int DSS=2;
  private static final int UNKNOWN=3;

  private static final int OPENSSH=0;
  private static final int FSECURE=1;
  private static final int PUTTY=2;

  private int type=ERROR;
  private int keytype=OPENSSH;

  private byte[] publickeyblob=null;

  private boolean encrypted=true;

  IdentityFile(String identity, JSch jsch) throws JSchException{
    this.identity=identity;
    this.jsch=jsch;
    try{
      Class c;
      c=Class.forName((String)jsch.getConfig("3des-cbc"));
      cipher=(Cipher)(c.newInstance());
      key=new byte[cipher.getBlockSize()];   // 24
      iv=new byte[cipher.getIVSize()];       // 8
      c=Class.forName((String)jsch.getConfig("md5"));
      hash=(HASH)(c.newInstance());
      hash.init();
      File file=new File(identity);
      FileInputStream fis = new FileInputStream(identity);
      byte[] buf=new byte[(int)(file.length())];
      int len=fis.read(buf, 0, buf.length);
      fis.close();

      int i=0;
      while(i<len){
        if(buf[i]=='B'&& buf[i+1]=='E'&& buf[i+2]=='G'&& buf[i+3]=='I'){
          i+=6;	    
          if(buf[i]=='D'&& buf[i+1]=='S'&& buf[i+2]=='A'){ type=DSS; }
	  else if(buf[i]=='R'&& buf[i+1]=='S'&& buf[i+2]=='A'){ type=RSA; }
	  else if(buf[i]=='S'&& buf[i+1]=='S'&& buf[i+2]=='H'){ // FSecure
	    type=UNKNOWN;
	    keytype=FSECURE;
	  }
	  else{
            //System.out.println("invalid format: "+identity);
	    throw new JSchException("invaid privatekey: "+identity);
	  }
          i+=3;
	  continue;
	}
        if(buf[i]=='C'&& buf[i+1]=='B'&& buf[i+2]=='C'&& buf[i+3]==','){
          i+=4;
	  for(int ii=0; ii<iv.length; ii++){
            iv[ii]=(byte)(((a2b(buf[i++])<<4)&0xf0)+
			  (a2b(buf[i++])&0xf));
  	  }
	  continue;
	}
	if(buf[i]==0x0d &&
	   i+1<buf.length && buf[i+1]==0x0a){
	  i++;
	  continue;
	}
	if(buf[i]==0x0a && i+1<buf.length){
	  if(buf[i+1]==0x0a){ i+=2; break; }
	  if(buf[i+1]==0x0d &&
	     i+2<buf.length && buf[i+2]==0x0a){
	     i+=3; break;
	  }
	  boolean inheader=false;
	  for(int j=i+1; j<buf.length; j++){
	    if(buf[j]==0x0a) break;
	    //if(buf[j]==0x0d) break;
	    if(buf[j]==':'){inheader=true; break;}
	  }
	  if(!inheader){
	    i++; 
	    encrypted=false;    // no passphrase
	    break;
	  }
	}
	i++;
      }

      if(type==ERROR){
	throw new JSchException("invaid privatekey: "+identity);
      }

      int start=i;
      while(i<len){
        if(buf[i]==0x0a){
	  boolean xd=(buf[i-1]==0x0d);
          System.arraycopy(buf, i+1, 
			   buf, 
			   i-(xd ? 1 : 0), 
			   len-i-1-(xd ? 1 : 0)
			   );
	  if(xd)len--;
          len--;
          continue;
        }
        if(buf[i]=='-'){  break; }
        i++;
      }
      encoded_data=Util.fromBase64(buf, start, i-start);

      if(encoded_data.length>4 &&            // FSecure
	 encoded_data[0]==(byte)0x3f &&
	 encoded_data[1]==(byte)0x6f &&
	 encoded_data[2]==(byte)0xf9 &&
	 encoded_data[3]==(byte)0xeb){

	Buffer _buf=new Buffer(encoded_data);
	_buf.getInt();  // 0x3f6ff9be
	_buf.getInt();
	byte[]_type=_buf.getString();
	//System.out.println("type: "+new String(_type)); 
	byte[] _cipher=_buf.getString();
	String cipher=new String(_cipher);
	//System.out.println("cipher: "+cipher); 
	if(cipher.equals("3des-cbc")){
  	   _buf.getInt();
	   byte[] foo=new byte[encoded_data.length-_buf.getOffSet()];
	   _buf.getByte(foo);
	   encoded_data=foo;
	   encrypted=true;
	   throw new JSchException("unknown privatekey format: "+identity);
	}
	else if(cipher.equals("none")){
  	   _buf.getInt();
  	   //_buf.getInt();

           encrypted=false;

	   byte[] foo=new byte[encoded_data.length-_buf.getOffSet()];
	   _buf.getByte(foo);
	   encoded_data=foo;
	}

      }

      try{
        file=new File(identity+".pub");
        fis=new FileInputStream(identity+".pub");
        buf=new byte[(int)(file.length())];
        len=fis.read(buf, 0, buf.length);
        fis.close();
      }
      catch(Exception ee){
	return;
      }

      if(buf.length>4 &&             // FSecure's public key
	 buf[0]=='-' && buf[1]=='-' && buf[2]=='-' && buf[3]=='-'){

	i=0;
	do{i++;}while(buf.length>i && buf[i]!=0x0a);
	if(buf.length<=i) return;

	while(true){
	  if(buf[i]==0x0a){
	    boolean inheader=false;
	    for(int j=i+1; j<buf.length; j++){
	      if(buf[j]==0x0a) break;
	      if(buf[j]==':'){inheader=true; break;}
	    }
	    if(!inheader){
	      i++; 
	      break;
	    }
	  }
	  i++;
	}
	if(buf.length<=i) return;

	start=i;
	while(i<len){
	  if(buf[i]==0x0a){
	    System.arraycopy(buf, i+1, buf, i, len-i-1);
	    len--;
	    continue;
	  }
	  if(buf[i]=='-'){  break; }
	  i++;
	}
	publickeyblob=Util.fromBase64(buf, start, i-start);

	if(type==UNKNOWN){
	  if(publickeyblob[8]=='d'){
	    type=DSS;
	  }
	  else if(publickeyblob[8]=='r'){
	    type=RSA;
	  }
	}
      }
      else{
	if(buf[0]!='s'|| buf[1]!='s'|| buf[2]!='h'|| buf[3]!='-') return;
	i=0;
	while(i<len){ if(buf[i]==' ')break; i++;} i++;
	if(i>=len) return;
	start=i;
	while(i<len){ if(buf[i]==' ')break; i++;}
	publickeyblob=Util.fromBase64(buf, start, i-start);
      }

    }
    catch(Exception e){
      System.out.println("Identity: "+e);
      if(e instanceof JSchException) throw (JSchException)e;
      throw new JSchException(e.toString());
    }

  }

  public String getAlgName(){
    if(type==RSA) return "ssh-rsa";
    return "ssh-dss"; 
  }

  public boolean setPassphrase(String _passphrase) throws JSchException{
    /*
      hash is MD5
      h(0) <- hash(passphrase, iv);
      h(n) <- hash(h(n-1), passphrase, iv);
      key <- (h(0),...,h(n))[0,..,key.length];
    */
    try{
      if(encrypted){
	if(_passphrase==null) return false;
	byte[] passphrase=_passphrase.getBytes();
	int hsize=hash.getBlockSize();
	byte[] hn=new byte[key.length/hsize*hsize+
			   (key.length%hsize==0?0:hsize)];
	byte[] tmp=null;
	if(keytype==OPENSSH){
	  for(int index=0; index+hsize<=hn.length;){
	    if(tmp!=null){ hash.update(tmp, 0, tmp.length); }
	    hash.update(passphrase, 0, passphrase.length);
	    hash.update(iv, 0, iv.length);
	    tmp=hash.digest();
	    System.arraycopy(tmp, 0, hn, index, tmp.length);
	    index+=tmp.length;
	  }
	  System.arraycopy(hn, 0, key, 0, key.length); 
	}
	else if(keytype==FSECURE){
	  for(int index=0; index+hsize<=hn.length;){
	    if(tmp!=null){ hash.update(tmp, 0, tmp.length); }
	    hash.update(passphrase, 0, passphrase.length);
	    tmp=hash.digest();
	    System.arraycopy(tmp, 0, hn, index, tmp.length);
	    index+=tmp.length;
	  }
	  System.arraycopy(hn, 0, key, 0, key.length); 
	}
        if(passphrase!=null){
          for(int i=0; i<passphrase.length; i++){
            passphrase[i]=0;
          }
          passphrase=null;
        }
      }
      if(decrypt()){
	encrypted=false;
	return true;
      }
      P_array=Q_array=G_array=pub_array=prv_array=null;
      return false;
    }
    catch(Exception e){
      if(e instanceof JSchException) throw (JSchException)e;
      throw new JSchException(e.toString());
    }
  }

  public byte[] getPublicKeyBlob(){
    if(publickeyblob!=null) return publickeyblob;
    if(type==RSA) return getPublicKeyBlob_rsa();
    return getPublicKeyBlob_dss();
  }

  byte[] getPublicKeyBlob_rsa(){
    if(e_array==null) return null;
    Buffer buf=new Buffer("ssh-rsa".length()+4+
			   e_array.length+4+ 
 			   n_array.length+4);
    buf.putString("ssh-rsa".getBytes());
    buf.putString(e_array);
    buf.putString(n_array);
    return buf.buffer;
  }

  byte[] getPublicKeyBlob_dss(){
    if(P_array==null) return null;
    Buffer buf=new Buffer("ssh-dss".length()+4+
			   P_array.length+4+ 
			   Q_array.length+4+ 
			   G_array.length+4+ 
			   pub_array.length+4);
    buf.putString("ssh-dss".getBytes());
    buf.putString(P_array);
    buf.putString(Q_array);
    buf.putString(G_array);
    buf.putString(pub_array);
    return buf.buffer;
  }

  public byte[] getSignature(byte[] data){
    if(type==RSA) return getSignature_rsa(data);
    return getSignature_dss(data);
  }

  byte[] getSignature_rsa(byte[] data){
    try{      
      Class c=Class.forName((String)jsch.getConfig("signature.rsa"));
      SignatureRSA rsa=(SignatureRSA)(c.newInstance());

      rsa.init();
      rsa.setPrvKey(d_array, n_array);

      /*
      byte[] goo=new byte[4];
      goo[0]=(byte)(session.getSessionId().length>>>24);
      goo[1]=(byte)(session.getSessionId().length>>>16);
      goo[2]=(byte)(session.getSessionId().length>>>8);
      goo[3]=(byte)(session.getSessionId().length);
      rsa.update(goo);
      rsa.update(session.getSessionId());
      */
      rsa.update(data);
      byte[] sig = rsa.sign();
      Buffer buf=new Buffer("ssh-rsa".length()+4+
			    sig.length+4);
      buf.putString("ssh-rsa".getBytes());
      buf.putString(sig);
      return buf.buffer;
    }
    catch(Exception e){
    }
    return null;
  }

  byte[] getSignature_dss(byte[] data){
/*
    byte[] foo;
    int i;
    System.out.print("P ");
    foo=P_array;
    for(i=0;  i<foo.length; i++){
      System.out.print(Integer.toHexString(foo[i]&0xff)+":");
    }
    System.out.println("");
    System.out.print("Q ");
    foo=Q_array;
    for(i=0;  i<foo.length; i++){
      System.out.print(Integer.toHexString(foo[i]&0xff)+":");
    }
    System.out.println("");
    System.out.print("G ");
    foo=G_array;
    for(i=0;  i<foo.length; i++){
      System.out.print(Integer.toHexString(foo[i]&0xff)+":");
    }
    System.out.println("");
*/

    try{      
      Class c=Class.forName((String)jsch.getConfig("signature.dss"));
      SignatureDSA dsa=(SignatureDSA)(c.newInstance());
      dsa.init();
      dsa.setPrvKey(prv_array, P_array, Q_array, G_array);

      /*
      byte[] goo=new byte[4];
      goo[0]=(byte)(session.getSessionId().length>>>24);
      goo[1]=(byte)(session.getSessionId().length>>>16);
      goo[2]=(byte)(session.getSessionId().length>>>8);
      goo[3]=(byte)(session.getSessionId().length);
      dsa.update(goo);
      dsa.update(session.getSessionId());
      */

      dsa.update(data);
      byte[] sig = dsa.sign();
      Buffer buf=new Buffer("ssh-dss".length()+4+
			    sig.length+4);
      buf.putString("ssh-dss".getBytes());
      buf.putString(sig);
      return buf.buffer;
    }
    catch(Exception e){
      //System.out.println("e "+e);
    }
    return null;
  }

  public boolean decrypt(){
    if(type==RSA) return decrypt_rsa();
    return decrypt_dss();
  }

  boolean decrypt_rsa(){
    byte[] p_array;
    byte[] q_array;
    byte[] dmp1_array;
    byte[] dmq1_array;
    byte[] iqmp_array;

    try{
      byte[] plain;
      if(encrypted){
	if(keytype==OPENSSH){
	  cipher.init(Cipher.DECRYPT_MODE, key, iv);
	  plain=new byte[encoded_data.length];
	  cipher.update(encoded_data, 0, encoded_data.length, plain, 0);
	}
	else if(keytype==FSECURE){
	  for(int i=0; i<iv.length; i++)iv[i]=0;
	  cipher.init(Cipher.DECRYPT_MODE, key, iv);
	  plain=new byte[encoded_data.length];
	  cipher.update(encoded_data, 0, encoded_data.length, plain, 0);
	}
	else{
	  return false;
	}
      }
      else{
	if(n_array!=null) return true;
	plain=encoded_data;
      }

      if(keytype==FSECURE){              // FSecure   
	Buffer buf=new Buffer(plain);
        int foo=buf.getInt();
        if(plain.length!=foo+4){
          return false;
        }
	e_array=buf.getMPIntBits();
        d_array=buf.getMPIntBits();
	n_array=buf.getMPIntBits();
	byte[] u_array=buf.getMPIntBits();
	p_array=buf.getMPIntBits();
	q_array=buf.getMPIntBits();
        return true;
      }

      int index=0;
      int length=0;

      if(plain[index]!=0x30)return false;
      index++; // SEQUENCE
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }

      if(plain[index]!=0x02)return false;
      index++; // INTEGER
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      index+=length;

//System.out.println("int: len="+length);
//System.out.print(Integer.toHexString(plain[index-1]&0xff)+":");
//System.out.println("");

      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      n_array=new byte[length];
      System.arraycopy(plain, index, n_array, 0, length);
      index+=length;
/*
System.out.println("int: N len="+length);
for(int i=0; i<n_array.length; i++){
System.out.print(Integer.toHexString(n_array[i]&0xff)+":");
}
System.out.println("");
*/
      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      e_array=new byte[length];
      System.arraycopy(plain, index, e_array, 0, length);
      index+=length;
/*
System.out.println("int: E len="+length);
for(int i=0; i<e_array.length; i++){
System.out.print(Integer.toHexString(e_array[i]&0xff)+":");
}
System.out.println("");
*/
      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      d_array=new byte[length];
      System.arraycopy(plain, index, d_array, 0, length);
      index+=length;
/*
System.out.println("int: D len="+length);
for(int i=0; i<d_array.length; i++){
System.out.print(Integer.toHexString(d_array[i]&0xff)+":");
}
System.out.println("");
*/

      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      p_array=new byte[length];
      System.arraycopy(plain, index, p_array, 0, length);
      index+=length;
/*
System.out.println("int: P len="+length);
for(int i=0; i<p_array.length; i++){
System.out.print(Integer.toHexString(p_array[i]&0xff)+":");
}
System.out.println("");
*/
      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      q_array=new byte[length];
      System.arraycopy(plain, index, q_array, 0, length);
      index+=length;
/*
System.out.println("int: q len="+length);
for(int i=0; i<q_array.length; i++){
System.out.print(Integer.toHexString(q_array[i]&0xff)+":");
}
System.out.println("");
*/
      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      dmp1_array=new byte[length];
      System.arraycopy(plain, index, dmp1_array, 0, length);
      index+=length;
/*
System.out.println("int: dmp1 len="+length);
for(int i=0; i<dmp1_array.length; i++){
System.out.print(Integer.toHexString(dmp1_array[i]&0xff)+":");
}
System.out.println("");
*/
      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      dmq1_array=new byte[length];
      System.arraycopy(plain, index, dmq1_array, 0, length);
      index+=length;
/*
System.out.println("int: dmq1 len="+length);
for(int i=0; i<dmq1_array.length; i++){
System.out.print(Integer.toHexString(dmq1_array[i]&0xff)+":");
}
System.out.println("");
*/
      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      iqmp_array=new byte[length];
      System.arraycopy(plain, index, iqmp_array, 0, length);
      index+=length;
/*
System.out.println("int: iqmp len="+length);
for(int i=0; i<iqmp_array.length; i++){
System.out.print(Integer.toHexString(iqmp_array[i]&0xff)+":");
}
System.out.println("");
*/
    }
    catch(Exception e){
      //System.out.println(e);
      return false;
    }
    return true;
  }

  boolean decrypt_dss(){
    try{
      byte[] plain;
      if(encrypted){
	if(keytype==OPENSSH){
	  cipher.init(Cipher.DECRYPT_MODE, key, iv);
	  plain=new byte[encoded_data.length];
	  cipher.update(encoded_data, 0, encoded_data.length, plain, 0);
/*
for(int i=0; i<plain.length; i++){
System.out.print(Integer.toHexString(plain[i]&0xff)+":");
}
System.out.println("");
*/
	}
	else if(keytype==FSECURE){
	  for(int i=0; i<iv.length; i++)iv[i]=0;
	  cipher.init(Cipher.DECRYPT_MODE, key, iv);
	  plain=new byte[encoded_data.length];
	  cipher.update(encoded_data, 0, encoded_data.length, plain, 0);
	}
	else{
	  return false;
	}
      }
      else{
	if(P_array!=null) return true;
	plain=encoded_data;
      }

      if(keytype==FSECURE){              // FSecure   
	Buffer buf=new Buffer(plain);
        int foo=buf.getInt();
        if(plain.length!=foo+4){
          return false;
        }
	P_array=buf.getMPIntBits();
        G_array=buf.getMPIntBits();
	Q_array=buf.getMPIntBits();
	pub_array=buf.getMPIntBits();
	prv_array=buf.getMPIntBits();
        return true;
      }

      int index=0;
      int length=0;
      if(plain[index]!=0x30)return false;
      index++; // SEQUENCE
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      if(plain[index]!=0x02)return false;
      index++; // INTEGER
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      index+=length;

      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      P_array=new byte[length];
      System.arraycopy(plain, index, P_array, 0, length);
      index+=length;

      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      Q_array=new byte[length];
      System.arraycopy(plain, index, Q_array, 0, length);
      index+=length;

      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      G_array=new byte[length];
      System.arraycopy(plain, index, G_array, 0, length);
      index+=length;

      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      pub_array=new byte[length];
      System.arraycopy(plain, index, pub_array, 0, length);
      index+=length;

      index++;
      length=plain[index++]&0xff;
      if((length&0x80)!=0){
        int foo=length&0x7f; length=0;
        while(foo-->0){ length=(length<<8)+(plain[index++]&0xff); }
      }
      prv_array=new byte[length];
      System.arraycopy(plain, index, prv_array, 0, length);
      index+=length;
    }
    catch(Exception e){
      //System.out.println(e);
      //e.printStackTrace();
      return false;
    }
    return true;
  }

  public boolean isEncrypted(){
    return encrypted;
  }
  public String getName(){return identity;}

  private int writeSEQUENCE(byte[] buf, int index, int len){
    buf[index++]=0x30;
    index=writeLength(buf, index, len);
    return index;
  }
  private int writeINTEGER(byte[] buf, int index, byte[] data){
    buf[index++]=0x02;
    index=writeLength(buf, index, data.length);
    System.arraycopy(data, 0, buf, index, data.length);
    index+=data.length;
    return index;
  }

  private int countLength(int len){
    int i=1;
    if(len<=0x7f) return i;
    while(len>0){
      len>>>=8;
      i++;
    }
    return i;
  }

  private int writeLength(byte[] data, int index, int len){
    int i=countLength(len)-1;
    if(i==0){
      data[index++]=(byte)len;
      return index;
    }
    data[index++]=(byte)(0x80|i);
    int j=index+i;
    while(i>0){
      data[index+i-1]=(byte)(len&0xff);
      len>>>=8;
      i--;
    }
    return j;
  }

  private byte a2b(byte c){
    if('0'<=c&&c<='9') return (byte)(c-'0');
    if('a'<=c&&c<='z') return (byte)(c-'a'+10);
    return (byte)(c-'A'+10);
  }
  private byte b2a(byte c){
    if(0<=c&&c<=9) return (byte)(c+'0');
    return (byte)(c-10+'A');
  }
}
