Error Decrypting file: common error I can't get past

Question

Hi,
How can I properly pad this code? I really have no idea how to do this, and after searching the forums for a while I cannot seem to find a clear answer.
If anyone could provide a link to an example of how to pad a value I would really appreciate it. I cannot seem to find this information anywhere...
Here is my code:
import java.io.*;
import java.util.*;
import java.math.BigInteger;
import java.security.*;
import java.security.spec.*;
import java.security.interfaces.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.crypto.interfaces.*;
import com.sun.crypto.provider.SunJCE;
public class encrypt {
    public static void main(String[] args) {
       try {
           BufferedReader input = new BufferedReader (new InputStreamReader(System.in));
           String src;
           String dest;
           char password[];
           char check[];
           boolean mustMatch;
           System.out.print ("Enter the full path to the source file> ");
           src = input.readLine();
           System.out.print ("Enter the full path for filename to use for encrypted file> ");
           dest = input.readLine();
           do {
              mustMatch = false;
              System.out.flush();
              System.out.print ("Enter password: ");
              password = readPasswd (System.in);
              System.out.print ("Confirm password: " );
              check = readPasswd (System.in);
              for (int i = 0; i < password.length; i++) {
                 if (password[i] != check) {
mustMatch = true;
} while (mustMatch);
encrypt.jarble (src, dest, password);
encrypt.dejarble (dest, password);
catch (IOException e) {
System.err.println("I/O Exception caught");
private static boolean dejarble (String file, char pass[]) {
try {
System.out.println ("encrypt.dejarble(): input file: " + file);
PBEKeySpec pbeKeySpec;
PBEParameterSpec pbeParamSpec;
SecretKeyFactory keyFac;
// Salt
byte[] salt = {
(byte)0xc7, (byte)0x73, (byte)0x21, (byte)0x8c,
(byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99
// Iteration count
int count = 20;
// Create PBE parameter set
pbeParamSpec = new PBEParameterSpec(salt, count);
pbeKeySpec = new PBEKeySpec(pass);
keyFac = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);
// Create PBE Cipher
Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
// Initialize PBE Cipher with key and parameters
pbeCipher.init(Cipher.DECRYPT_MODE, pbeKey, pbeParamSpec);
// pad our data
long fileLength = (new File(file)).length();
double padding = (Math.ceil(fileLength / 8)+1)*8;
System.out.println ("complete size: " + padding);
int blah = (new Double(padding)).intValue();
System.out.println("proposed array size: " + blah);
byte[] fileData = new byte[blah];
byte[] buffer_test;
// javax.crypto.BadPaddingException: Given final block not properly padded
// pad our data with zero
for (int i = (int) fileLength; i < fileData.length; i++)
fileData[i] = (new Byte("0")).byteValue();
System.out.println ("size of fileData: " + fileData.length);
buffer_test = encrypt.getBytesFromFile (file);
for (int i = 0; i < buffer_test.length; i++) {
fileData[i] = buffer_test[i];
byte[] cleartext = pbeCipher.doFinal(fileData);
String asdf = new String (cleartext);
System.out.println("Decrypted text:");
System.out.println (asdf);
return true;
catch (Exception e) {
System.out.println ("encrypt(): exception caught: " + e.toString());
System.out.println ("encrypt(): exception message: " + e.getMessage());
return false;
// This function started from an example provided at the following web page:
// http://java.sun.com/j2se/1.4.2/docs/guide/security/jce/JCERefGuide.html
private static boolean jarble (String file, String output, char pass[]) {
try {
PBEKeySpec pbeKeySpec;
PBEParameterSpec pbeParamSpec;
SecretKeyFactory keyFac;
// Salt
byte[] salt = {
(byte)0xc7, (byte)0x73, (byte)0x21, (byte)0x8c,
(byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99
// Iteration count
int count = 20;
// Create PBE parameter set
pbeParamSpec = new PBEParameterSpec(salt, count);
pbeKeySpec = new PBEKeySpec(pass);
keyFac = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);
// Create PBE Cipher
Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
// Initialize PBE Cipher with key and parameters
pbeCipher.init(Cipher.ENCRYPT_MODE, pbeKey, pbeParamSpec);
byte[] cleartext = encrypt.getBytesFromFile (file);
String asdf = new String (cleartext, "UTF-8");
System.out.println("encrypt(): original text");
System.out.println (asdf);
// Encrypt the cleartext
byte[] ciphertext = pbeCipher.doFinal(cleartext);
asdf = new String (ciphertext, "UTF-8");
System.out.println ("encrypt(): encrypted text");
System.out.println (asdf);
// write the file
FileOutputStream out;
PrintStream p;
out = new FileOutputStream (output);
p = new PrintStream (out);
p.println(asdf);
p.close();
return true;
catch (Exception e) {
System.out.println ("jarble(): exception caught: " + e.toString());
System.out.println ("jarble(): exception message: " + e.getMessage());
return false;
// Returns the contents of the file in a byte array.
private static byte[] getBytesFromFile(String str) throws IOException {
File file = new File (str);
InputStream is = new FileInputStream(file);
// Get the size of the file
long length = file.length();
// You cannot create an array using a long type.
// It needs to be an int type.
// Before converting to an int type, check
// to ensure that file is not larger than Integer.MAX_VALUE.
if (length > Integer.MAX_VALUE) {
// File is too large
return null;
// Create the byte array to hold the data
byte[] bytes = new byte[(int)length];
// Read in the bytes
int offset = 0;
int numRead = 0;
while (offset < bytes.length
&& (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) {
offset += numRead;
// Ensure all the bytes have been read in
if (offset < bytes.length) {
throw new IOException("Could not completely read file "+file.getName());
// Close the input stream and return bytes
is.close();
return bytes;
* Reads user password from given input stream.
private static char[] readPasswd(InputStream in) throws IOException {
char[] lineBuffer;
char[] buf;
int i;
buf = lineBuffer = new char[128];
int room = buf.length;
int offset = 0;
int c;
loop: while (true) {
switch (c = in.read()) {
case -1:
case '\n':
break loop;
case '\r':
int c2 = in.read();
if ((c2 != '\n') && (c2 != -1)) {
if (!(in instanceof PushbackInputStream)) {
in = new PushbackInputStream(in);
((PushbackInputStream)in).unread(c2);
} else
break loop;
default:
if (--room < 0) {
buf = new char[offset + 128];
room = buf.length - offset - 1;
System.arraycopy(lineBuffer, 0, buf, 0, offset);
Arrays.fill(lineBuffer, ' ');
lineBuffer = buf;
buf[offset++] = (char) c;
break;
if (offset == 0) {
return null;
char[] ret = new char[offset];
System.arraycopy(buf, 0, ret, 0, offset);
Arrays.fill(buf, ' ');
return ret;

Answer 1

Hey Thanks man! You're awesome!!!
Here is the code that works for anyone that searches through this thread looking for help:
import java.io.*;
import java.util.*;
import java.math.BigInteger;
import java.security.*;
import java.security.spec.*;
import java.security.interfaces.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.crypto.interfaces.*;
import com.sun.crypto.provider.SunJCE;
public class encrypt {
    public static void main(String[] args) {
       try {
           BufferedReader input = new BufferedReader (new InputStreamReader(System.in));
           String src;
           String dest;
           char password[];
           char check[];
           boolean mustMatch;
           System.out.print ("Enter the full path to the source file> ");
           src = input.readLine();
           System.out.print ("Enter the full path for filename to use for encrypted file> ");
           dest = input.readLine();
           do {
              mustMatch = false;
              System.out.flush();
              System.out.print ("Enter password: ");
              password = readPasswd (System.in);
              System.out.print ("Confirm password: " );
              check = readPasswd (System.in);
              for (int i = 0; i < password.length; i++) {
                 if (password[i] != check) {
mustMatch = true;
} while (mustMatch);
encrypt.jarble (src, dest, password);
encrypt.dejarble (dest, password);
catch (IOException e) {
System.err.println("I/O Exception caught");
private static boolean dejarble (String file, char pass[]) {
try {
System.out.println ("encrypt.dejarble(): input file: " + file);
PBEKeySpec pbeKeySpec;
PBEParameterSpec pbeParamSpec;
SecretKeyFactory keyFac;
// Salt
byte[] salt = {
(byte)0xc7, (byte)0x73, (byte)0x21, (byte)0x8c,
(byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99
// Iteration count
int count = 20;
// Create PBE parameter set
pbeParamSpec = new PBEParameterSpec(salt, count);
pbeKeySpec = new PBEKeySpec(pass);
keyFac = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);
// Create PBE Cipher
Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
// Initialize PBE Cipher with key and parameters
pbeCipher.init(Cipher.DECRYPT_MODE, pbeKey, pbeParamSpec);
byte fileData[] = encrypt.getBytesFromFile (file);
byte[] cleartext = pbeCipher.doFinal(fileData);
String asdf = new String (cleartext, "UTF-8");
System.out.println("Decrypted text:");
System.out.println (asdf);
return true;
catch (Exception e) {
System.out.println ("encrypt(): exception caught: " + e.toString());
System.out.println ("encrypt(): exception message: " + e.getMessage());
return false;
// This function started from an example provided at the following web page:
// http://java.sun.com/j2se/1.4.2/docs/guide/security/jce/JCERefGuide.html
private static boolean jarble (String file, String output, char pass[]) {
try {
PBEKeySpec pbeKeySpec;
PBEParameterSpec pbeParamSpec;
SecretKeyFactory keyFac;
// Salt
byte[] salt = {
(byte)0xc7, (byte)0x73, (byte)0x21, (byte)0x8c,
(byte)0x7e, (byte)0xc8, (byte)0xee, (byte)0x99
// Iteration count
int count = 20;
// Create PBE parameter set
pbeParamSpec = new PBEParameterSpec(salt, count);
pbeKeySpec = new PBEKeySpec(pass);
keyFac = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);
// Create PBE Cipher
Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
// Initialize PBE Cipher with key and parameters
pbeCipher.init(Cipher.ENCRYPT_MODE, pbeKey, pbeParamSpec);
byte[] cleartext = encrypt.getBytesFromFile (file);
String asdf = new String (cleartext, "UTF-8");
System.out.println("encrypt(): original text");
System.out.println (asdf);
// Encrypt the cleartext
byte[] ciphertext = pbeCipher.doFinal(cleartext);
asdf = new String (ciphertext, "UTF-8");
System.out.println ("encrypt(): encrypted text");
System.out.println (asdf);
// write the file
DataOutputStream out = new DataOutputStream (new FileOutputStream (output));
out.write (ciphertext, 0, ciphertext.length);
System.err.println (ciphertext.length);
out.close();
return true;
catch (Exception e) {
System.out.println ("jarble(): exception caught: " + e.toString());
System.out.println ("jarble(): exception message: " + e.getMessage());
return false;
// Returns the contents of the file in a byte array.
private static byte[] getBytesFromFile(String str) throws IOException {
File file = new File (str);
InputStream is = new FileInputStream(file);
// Get the size of the file
long length = file.length();
// You cannot create an array using a long type.
// It needs to be an int type.
// Before converting to an int type, check
// to ensure that file is not larger than Integer.MAX_VALUE.
if (length > Integer.MAX_VALUE) {
// File is too large
return null;
// Create the byte array to hold the data
byte[] bytes = new byte[(int)length];
// Read in the bytes
int offset = 0;
int numRead = 0;
while (offset < bytes.length
&& (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) {
offset += numRead;
// Ensure all the bytes have been read in
if (offset < bytes.length) {
throw new IOException("Could not completely read file "+file.getName());
// Close the input stream and return bytes
is.close();
return bytes;
* Reads user password from given input stream.
private static char[] readPasswd(InputStream in) throws IOException {
char[] lineBuffer;
char[] buf;
int i;
buf = lineBuffer = new char[128];
int room = buf.length;
int offset = 0;
int c;
loop: while (true) {
switch (c = in.read()) {
case -1:
case '\n':
break loop;
case '\r':
int c2 = in.read();
if ((c2 != '\n') && (c2 != -1)) {
if (!(in instanceof PushbackInputStream)) {
in = new PushbackInputStream(in);
((PushbackInputStream)in).unread(c2);
} else
break loop;
default:
if (--room < 0) {
buf = new char[offset + 128];
room = buf.length - offset - 1;
System.arraycopy(lineBuffer, 0, buf, 0, offset);
Arrays.fill(lineBuffer, ' ');
lineBuffer = buf;
buf[offset++] = (char) c;
break;
if (offset == 0) {
return null;
char[] ret = new char[offset];
System.arraycopy(buf, 0, ret, 0, offset);
Arrays.fill(buf, ' ');
return ret;