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Send file encrypted (Server) and receive file decrypted (Client) with AES 256

Im sending a file from Server to a Client but i need to send a encrypted file with AES 256 and receive a original for client use in diferente machine.
I want use 2 string to generate a SHA256 for example: "fruit" and "car29".
After generate this key I want to use this key as secretkey to encrypt with AES256.The client and server know the two strings.
My server code:
public final static int SOCKET_PORT = 4444;
public final static String FILE_TO_SEND = "C:\\file.txt";
public static void main(String[] args) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
FileInputStream fis = null;
BufferedInputStream bis = null;
OutputStream os = null;
ServerSocket servsock = null;
Socket sock = null;
try {
servsock = new ServerSocket(SOCKET_PORT);
while (true) {
System.out.println("Waiting...");
try {
sock = servsock.accept();
System.out.println("Accepted connection : " + sock);
// send file
File myFile = new File(FILE_TO_SEND);
byte[] mybytearray = new byte[(int) myFile.length()];
fis = new FileInputStream(myFile);
bis = new BufferedInputStream(fis);
bis.read(mybytearray, 0, mybytearray.length);
os = sock.getOutputStream();
System.out.println("Sending " + FILE_TO_SEND + "(" + mybytearray.length + " bytes)");
os.write(mybytearray, 0, mybytearray.length);
os.flush();
System.out.println("Done.");
} finally {
if (bis != null) {
bis.close();
}
if (os != null) {
os.close();
}
if (sock != null) {
sock.close();
}
}
}
} finally {
if (servsock != null) {
servsock.close();
}
}
}
My client code:
public final static int SOCKET_PORT = 4444;
public final static String SERVER = "127.0.0.1";
public final static String FILE_TO_RECEIVED = "C:\\file.txt";
public final static int FILE_SIZE = 6022386;
public static void main (String [] args ) throws IOException {
int bytesRead;
int current = 0;
FileOutputStream fos = null;
BufferedOutputStream bos = null;
Socket sock = null;
try {
sock = new Socket(SERVER, SOCKET_PORT);
System.out.println("Connecting...");
// receive file
byte [] mybytearray = new byte [FILE_SIZE];
InputStream is = sock.getInputStream();
fos = new FileOutputStream(FILE_TO_RECEIVED);
bos = new BufferedOutputStream(fos);
bytesRead = is.read(mybytearray,0,mybytearray.length);
current = bytesRead;
do {
bytesRead =
is.read(mybytearray, current, (mybytearray.length-current));
if(bytesRead >= 0) current += bytesRead;
} while(bytesRead > -1);
bos.write(mybytearray, 0 , current);
bos.flush();
System.out.println("File " + FILE_TO_RECEIVED
+ " downloaded (" + current + " bytes read)");
}
finally {
if (fos != null) fos.close();
if (bos != null) bos.close();
if (sock != null) sock.close();
}
}
Thanks in advance!

There's some function I write for you, check it out.
For generating HASH/Digest:
public byte[] generateHASH(byte[] message) throws Exception {
MessageDigest messageDigest = MessageDigest.getInstance("SHA-256");
byte[] hash = messageDigest.digest(message);
return hash;
}
For Encryption:
public byte[] encrypt(byte[] msg, byte[] key, byte[] iv) throws Exception {
//prepare key
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
//prepare cipher
String cipherALG = "AES/CBC/PKCS5padding"; // use your preferred algorithm
Cipher cipher = Cipher.getInstance(cipherALG);
String string = cipher.getAlgorithm();
//as iv (Initial Vector) is only required for CBC mode
if (string.contains("CBC")) {
IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);
} else {
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
}
byte[] encMessage = cipher.doFinal(msg);
return encMessage;
}
For Decryption:
public byte[] decrypt(byte[] encMsgtoDec, byte[] key, byte[] iv) throws Exception {
//prepare key
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
//prepare cipher
String cipherALG = "AES/CBC/PKCS5padding"; // use your preferred algorithm
Cipher cipher = Cipher.getInstance(cipherALG);
String string = cipher.getAlgorithm();
//as iv (Initial Vector) is only required for CBC mode
if (string.contains("CBC")) {
IvParameterSpec ivParameterSpec = new IvParameterSpec(iv);
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);
} else {
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
}
byte[] decMsg = cipher.doFinal(encMsgtoDec);
return decMsg;
}
Note:
If you use CBC mode, then both encrypt() and decrypt() use same iv, otherwise you don't need iv, and of course key is same for both.
Your key generation process is naive. You better use RSA public key encryption for key exchange or Diffie–Hellman key exchange method for secret key transfer.

I would suggest you to use SSL. The data encryption comes by default. The SSL handshake takes care of generating and exchanging the encryption keys and subsequently encrypting the data from the source and decrypting it at the receiving end. All this happens at the transport layer and the application does not have to bother or do anything explicit except for configuring it to use SSL.

decrypting a file on server, checking its hash and digital signature and then encrypting it again and saving on file server

My application requires the users to upload digitally signed pdf and then encrypt the file. This encrypted file is then uploaded on server, where it is decrypted. The decrypted file is then verified by matching the hash of file and digital signature. Now this file is encrypted with using AES algorithm. Once encryption is completed the file is then stored on file server. The size of file could go upto 80mb.
The challenge I am facing now is that when the encrypted file is stored on local drive of machine the files get saved instantly but when the file server is on another machine it takes upto 30 min to save a single file. I am not able to figure out the reason for it.
Following is the code which I am using. I have deployed and tried in tomcat 6 and IBM WAS. The file transfer takes the same time when transferring to file server. The file server is connected to Application server via SAN network.
Following is my encryption code
strSymAlg = rb.getString("SYM_KEY_ALG"); //SYM_KEY_ALG=AES
cipher = Cipher.getInstance(strSymAlg);
SecKey = new SecretKeySpec(hex2Byte(sSymmetricKey), strSymAlg);
cipher.init(Cipher.DECRYPT_MODE, SecKey);
baos = recoverFile(new FileInputStream(fileEnv), cipher);
if (baos != null && isRecoveredFileValid((InputStream) new ByteArrayInputStream(baos.toByteArray()))) {
fileRecovered = (InputStream) new ByteArrayInputStream(baos.toByteArray());
}
}
private ByteArrayOutputStream recoverFile(FileInputStream in, Cipher cipher) {
int blockSize = cipher.getBlockSize();
int outputSize = cipher.getOutputSize(blockSize);
byte[] inBytes = new byte[blockSize];
byte[] outBytes = new byte[outputSize];
int inLength = 0;
int outLength = 0;
boolean more = true;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try {
while (more) {
inLength = in.read(inBytes);
if (inLength == blockSize) {
outLength = cipher.update(inBytes, 0, blockSize, outBytes);
baos.write(outBytes, 0, outLength);
} else {
more = false;
}
}
if (inLength > 0) {
outBytes = cipher.doFinal(inBytes, 0, inLength);
} else {
outBytes = cipher.doFinal();
}
baos.write(outBytes);
} catch (Exception e) {
System.out.println("recoverFile1: " + e.getMessage());
// e.printStackTrace();
baos = null;
}
return baos;
}
my encryption code is
String strSymKey = "";
File fileToCreate = null;
KeyGenerator keygen = KeyGenerator.getInstance(strSymAlg);
random = new SecureRandom();
keygen.init(random);
SecretKey secKey = keygen.generateKey();
Key publicKey = getPublicKeyFromString(sPubKey.trim());
//encrypt Symmetric key with public key
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.WRAP_MODE, publicKey);
byte[] wrappedKey = cipher.wrap(secKey);
strSymKey = byte2hex(wrappedKey);
fileToCreate = new File(strFile);
if (fileToCreate.exists()) {
fileToCreate.delete();
}
//Encrypt Bidder file with symmetric key
DataOutputStream out = new DataOutputStream(new FileOutputStream(strFile));
cipher = Cipher.getInstance(strSymAlg);
cipher.init(Cipher.ENCRYPT_MODE, secKey);
crypt(fis, out, cipher);
fis.close();
out.close();
//blnDone=true;
// System.out.println("STRING SYMMETRIC KEY:"+ strSymKey);
return strSymKey;
public String byte2hex(byte[] b) {
// String Buffer can be used instead
String hs = "";
String stmp = "";
for (int n = 0; n < b.length; n++) {
stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));
if (stmp.length() == 1) {
hs = hs + "0" + stmp;
} else {
hs = hs + stmp;
}
if (n < b.length - 1) {
hs = hs + "";
}
}
return hs;
}
New Function added
public void crypt(InputStream in, OutputStream out, Cipher cipher) throws IOException, GeneralSecurityException {
System.out.println("crypt start time :"+ new Date());
int blockSize = cipher.getBlockSize();
int outputSize = cipher.getOutputSize(blockSize);
byte[] inBytes = new byte[blockSize];
byte[] outBytes = new byte[outputSize];
int inLength = 0;
boolean more = true;
while (more) {
inLength = in.read(inBytes);
if (inLength == blockSize) {
int outLength = cipher.update(inBytes, 0, blockSize, outBytes);
out.write(outBytes, 0, outLength);
} else {
more = false;
}
}
if (inLength > 0) {
outBytes = cipher.doFinal(inBytes, 0, inLength);
} else {
outBytes = cipher.doFinal();
}
System.out.println("crypt end time :"+ new Date());
out.write(outBytes);
}
Thanks in advance

You are making the classic mistake of assuming that every read fills the buffer, and another: that it won't do so at end of stream. Neither is correct.
while ((count = in.read(buffer)) >= 0)
{
out.write(cipher.update(buffer, 0, count));
}
out.write(cipher.doFinal());
You don't need a DataOutputStream for this.

pdf encrypt compute /O

In order to properly understand the operation of the standard security handler in pdf
I am trying to reconstruct the entry /o e /u of the encryption dictionary from a previously encrypted pdf.
The encryption dictionary over /o and /u contains:
/P -1852
/CF
<<
/StdCF
<<
/AuthEvent /DocOpen
/Length 16
/CFM/V2
>>
>>
/R 4
/StmF /StdCF
/Filter/Standard
I managed to successfully reconstruct /o but I can not rebuild /u
main:
public static void main(String[] args) {
String docID;
byte[] userPass=null;
byte[] ownerPass=null;
try {
userPass = userPassString.getBytes("ISO-8859-1");
ownerPass = ownerPassString.getBytes("ISO-8859-1");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
try {
PDDocument doc=PDDocument.load(outPDfDir + "/EncryptedDocument_rc4_128.pdf");
if (doc.isEncrypted()){
EncryptDocument encrypt = new EncryptDocument(userPass,ownerPass,outPDfDir,doc.getEncryptionDictionary().getLength());
encrypt.setRevision(doc.getEncryptionDictionary().getRevision());
encrypt.setVersion(doc.getEncryptionDictionary().getVersion());
COSArray cosArray = doc.getDocument().getDocumentID();
docID=cosArray.getString(0); //only first entry of the array
byte[][] keys = encrypt.computeKeys(userPass, ownerPass, doc.getEncryptionDictionary().getPermissions(), docID.getBytes());
byte[] originalUserKey = doc.getEncryptionDictionary().getUserKey();
byte[] originalownerKey = doc.getEncryptionDictionary().getOwnerKey();
System.out.println(toHex(originalUserKey));
System.out.println(toHex(keys[1]));
if (Arrays.equals(originalUserKey,keys[1])){
System.out.println("User correctly authenticated");
}else{
System.out.println("wrong user password");
}
if (Arrays.equals(originalownerKey,keys[0])){
System.out.println("Owner correctly authenticated");
}else{
System.out.println("wrong user password");
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
Encrypt class
public class EncryptDocument {
private ARCFour rc4 = new ARCFour();
public static final byte[] ENCRYPT_PADDING = new byte[]{(byte)40, (byte)-65, (byte)78, (byte)94, (byte)78, (byte)117, (byte)-118, (byte)65, (byte)100, (byte)0, (byte)78, (byte)86, (byte)-1, (byte)-6, (byte)1, (byte)8, (byte)46, (byte)46, (byte)0, (byte)-74, (byte)-48, (byte)104, (byte)62, (byte)-128, (byte)47, (byte)12, (byte)-87, (byte)-2, (byte)100, (byte)83, (byte)105, (byte)122};
byte[] userPass;
byte[] ownerPass;
String destPath;
int revision;
int version;
private static final byte[] pad = new byte[]{(byte)40, (byte)-65, (byte)78, (byte)94, (byte)78, (byte)117, (byte)-118, (byte)65, (byte)100, (byte)0, (byte)78, (byte)86, (byte)-1, (byte)-6, (byte)1, (byte)8, (byte)46, (byte)46, (byte)0, (byte)-74, (byte)-48, (byte)104, (byte)62, (byte)-128, (byte)47, (byte)12, (byte)-87, (byte)-2, (byte)100, (byte)83, (byte)105, (byte)122};
private int keyLength;
public EncryptDocument(byte[] userPass, byte[] ownerPass, String destPath,int keylength) {
this.userPass = userPass;
this.ownerPass = ownerPass;
this.destPath = destPath;
this.keyLength=keylength;
}
public byte[][] computeKeys(byte[] userPass, byte[] ownPass, int permissions, byte[] documentId) {
//pad both user and owner pass
byte[] userPad = padPassword(userPass);
byte[] ownerPad = padPassword(ownPass);
byte[][] data = new byte[2][32];
byte[] userKey = new byte[0];
byte[] encryptionKey;
permissions= computePermissions(permissions);
byte[] ownerKey = new byte[0];
try {
ownerKey = computeOwnerKey(userPad, ownerPad);
encryptionKey = computeEncryptionKey(userPad,ownerKey,documentId,permissions);
userKey = computeUserKey(userPad,ownerKey,permissions,documentId,encryptionKey);
} catch (IOException e) {
e.printStackTrace();
}
data[0]=ownerKey;
data[1]=userKey;
return data;
}
private byte[] computeUserKey(byte[] userPad, byte[] ownerKey, int permissions, byte[] documentId, byte[] mkey) throws IOException {
//algorithm 5
byte[] digest;
ByteArrayOutputStream userKey = new ByteArrayOutputStream();
ARCFour rc4 = new ARCFour();
MessageDigest md5 = null;
try {
md5 = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
md5.update(pad); // step b
digest = md5.digest(documentId); //c
//build the input of rc4 encryption
userKey.write(digest);
byte[] iterationKey = new byte[mkey.length];
//encrypt it first time plus other 19 times
for (int i = 0; i < 20; ++i) {
System.arraycopy(mkey, 0, iterationKey, 0, iterationKey.length);
for (int input = 0; input < iterationKey.length; ++input) {
iterationKey[input] = (byte) (iterationKey[input] ^ i);
}
rc4.setKey(iterationKey);
ByteArrayInputStream tmpRes = new ByteArrayInputStream(userKey.toByteArray());
userKey.reset();
rc4.write(tmpRes, userKey);
}
return userKey.toByteArray();
}
private byte[] computeEncryptionKey(byte[] userPad,byte[] ownerKey, byte[] documentId,int permissions){
//initialize hash function
MessageDigest md5 = null;
byte[] encryptedKey =new byte[keyLength / 8];
byte[] digest;
try {
md5 = MessageDigest.getInstance("MD5"); //md5.reset()
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
md5.update(userPad);///pass the padded user password (step b)
md5.update(ownerKey); //pass o entry to the hash function (step c)
byte[] ext = int_to_bb_le(permissions); //new byte[]{(byte)permissions, (byte)(permissions >> 8), (byte)(permissions >> 16), (byte)(permissions >> 24)};
md5.update(ext, 0, 4); //pass permission to the hash function stp d
md5.update(documentId); //pass first element of document id (step e)
if (this.revision>=4)
md5.update(new byte[]{(byte)-1, (byte)-1, (byte)-1, (byte)-1}); //metadata not encryped --> add padding (step f)
digest = md5.digest();
//compute encryption key step g
if(revision == 3 || revision == 4) { //do 50 times step h
for(int k = 0; k < 50; ++k) {
md5.reset();
md5.update(digest,0,keyLength / 8);
digest=md5.digest();
}
}
System.arraycopy(digest, 0, encryptedKey, 0, encryptedKey.length);
return encryptedKey;
}
private byte[] computeOwnerKey(byte[] userPad, byte[] ownerPad) throws IOException {
MessageDigest md5 = null;
ARCFour rc4 = new ARCFour();
try {
md5 = MessageDigest.getInstance("MD5"); //md5.reset()
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
byte[] digest = md5.digest(ownerPad);
byte[] mkey = new byte[this.keyLength / 8];
int i;
for (i = 0; i < 50; ++i) {
md5.update(digest, 0, mkey.length);
System.arraycopy(md5.digest(), 0, digest, 0, mkey.length);
}
//encrypt the padded user password using the result of md5 computation on owner padded password
//revision >3 ==> do it 19 times
ByteArrayOutputStream ownerKey = new ByteArrayOutputStream();
//System.arraycopy(userPad, 0, ownerKey, 0, 32);
rc4.write(new ByteArrayInputStream(userPad), ownerKey);
byte[] iterationKey = new byte[mkey.length];
for (i = 0; i < 20; ++i) {
System.arraycopy(mkey, 0, iterationKey, 0, mkey.length);
//prepare encryption key bitwhise xor between encrypted owner padded password and iteration counter
for (int j = 0; j < iterationKey.length; ++j) {
iterationKey[j] = (byte) (digest[j] ^ i);
}
//encrypt with arc4
rc4.setKey(iterationKey);
ByteArrayInputStream tmpres = new ByteArrayInputStream(ownerKey.toByteArray());
ownerKey.reset();
rc4.write(tmpres, ownerKey);
}
//at the 19 invocation the own key is obtained
return ownerKey.toByteArray();
}
public int computePermissions(int permissions){
permissions |= this.revision != 3 && this.revision != 4 && this.revision != 5?-64:-3904;
permissions &= -4;
return permissions;
}
public byte[] padPassword(byte[] password) {
byte[] userPad = new byte[32];
if(password == null) {
System.arraycopy(pad, 0, userPad, 0, 32);
} else {
System.arraycopy(password, 0, userPad, 0, Math.min(password.length, 32));
if(password.length < 32) {
System.arraycopy(pad, 0, userPad, password.length, 32 - password.length);
}
}
return userPad;
}
public static byte[] int_to_bb_le(int myInteger){
return ByteBuffer.allocate(4).order(ByteOrder.LITTLE_ENDIAN).putInt(myInteger).allocatelocaterray();
}
}
someone is able to understand where I'm wrong?

En-/decrypt "AES/ECB/PKCS5Padding" in Java

Could anyone tell me how I would decrypt data (using Java) that has been encrypted with this PHP function?
PHP Code
public function pad($data, $blocksize = 16) {
$pad = $blocksize - (strlen($data) % $blocksize);
return $data . str_repeat(chr($pad), $pad);
}
public function decryptECB($data) {
return mcrypt_decrypt(MCRYPT_RIJNDAEL_128, self::BLOB_ENCRYPTION_KEY, self::pad($data), MCRYPT_MODE_ECB);
}
public function encryptECB($data) {
return mcrypt_encrypt(MCRYPT_RIJNDAEL_128, self::BLOB_ENCRYPTION_KEY, self::pad($data), MCRYPT_MODE_ECB);
}
I have tried most of the things here but most of them are without padding and even when I add padding they don't work.
Edit 1:
(From PHP)
The input looks like this: http://pastebin.com/2cyig9nh
Key is this:
M02cnQ51Ji97vwT4
And output is this: http://pastebin.com/XcA50UGH
(The Java code)
public class Mcrypt {
private SecretKeySpec keyspec;
private Cipher cipher;
private String SecretKey = "M02cnQ51Ji97vwT4";
public Mcrypt() {
keyspec = new SecretKeySpec(SecretKey.getBytes(), "AES");
try {
cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
}
}
public String encrypt(String text) throws Exception {
if (text == null || text.length() == 0)
throw new Exception("Empty string");
byte[] encrypted = null;
try {
cipher.init(Cipher.ENCRYPT_MODE, keyspec );
encrypted = cipher.doFinal(padString(text).getBytes());
} catch (Exception e) {
throw new Exception("[encrypt] " + e.getMessage());
}
return Base64.encodeBase64String(encrypted);
}
public byte[] decrypt(String code) throws Exception {
if (code == null || code.length() == 0)
throw new Exception("Empty string");
byte[] decrypted = null;
try {
cipher.init(Cipher.DECRYPT_MODE, keyspec );
decrypted = cipher.doFinal(new Base64().decode(code.getBytes()));
} catch (Exception e) {
throw new Exception("[decrypt] " + e.getMessage());
}
return decrypted;
}
private static String padString(String source) {
char paddingChar = ' ';
int size = 16;
int x = source.length() % size;
int padLength = size - x;
for (int i = 0; i < padLength; i++) {
source += paddingChar;
}
return source;
}
}

You are encoding and decoding to Base64 in your Java code, but your PHP code does not seem to perform any encoding/decoding whatsoever. This seems to be confirmed by what you posted on Pastebin. If you want to use strings instead of bytes - bytes are the only input accepted by modern ciphers - then you should make sure that the (character) encoding is correct on both sides. If you just want to use bytes, don't decode the binary in Java - the input is already in bytes, not text.

Can you figure out why this program is triggering a IllegalStateException?

all files in ~/Cipher/nsdl/crypto can be found here
java files compiled with gcj, see compile.sh
nmint#nqmk-mint ~/Cipher/nsdl/crypto $ echo test | ./cryptTest encrypt deadbeefdeadbeefdeadbeefdeadbeef deadbeef Blowfish CBC > test
null
Exception in thread "main" java.lang.IllegalStateException: cipher is not for encrypting or decrypting
at javax.crypto.Cipher.update(libgcj.so.81)
at javax.crypto.CipherOutputStream.write(libgcj.so.81)
at nsdl.crypto.BlockCrypt.encrypt(cryptTest)
at nsdl.crypto.cryptTest.main(cryptTest)
BlockCrypt.java:
package nsdl.crypto;
import java.io.*;
import java.security.spec.*;
import javax.crypto.*;
import javax.crypto.spec.*;
public class BlockCrypt {
Cipher ecipher;
Cipher dcipher;
byte[] keyBytes;
byte[] ivBytes;
SecretKey key;
AlgorithmParameterSpec iv;
byte[] buf = new byte[1024];
BlockCrypt(String keyStr, String ivStr, String algorithm, String mode) {
try {
ecipher = Cipher.getInstance(algorithm + "/" + mode + "/PKCS5Padding");
dcipher = Cipher.getInstance(algorithm + "/" + mode + "/PKCS5Padding");
keyBytes = hexStringToByteArray(keyStr);
ivBytes = hexStringToByteArray(ivStr);
key = new SecretKeySpec(keyBytes, algorithm);
iv = new IvParameterSpec(ivBytes);
ecipher.init(Cipher.ENCRYPT_MODE, key, iv);
dcipher.init(Cipher.DECRYPT_MODE, key, iv);
} catch (Exception e) {
System.err.println(e.getMessage());
}
}
public void encrypt(InputStream in, OutputStream out) {
try {
// out: where the plaintext goes to become encrypted
out = new CipherOutputStream(out, ecipher);
// in: where the plaintext comes from
int numRead = 0;
while ((numRead = in.read(buf)) >= 0) {
out.write(buf, 0, numRead);
}
out.close();
} catch (IOException e) {
System.err.println(e.getMessage());
}
}
public void decrypt(InputStream in, OutputStream out) {
try {
// in: where the plaintext come from, decrypted on-the-fly
in = new CipherInputStream(in, dcipher);
// out: where the plaintext goes
int numRead = 0;
while ((numRead = in.read(buf)) >= 0) {
out.write(buf, 0, numRead);
}
out.flush();
out.close();
} catch (IOException e) {
System.err.println(e.getMessage());
}
}
public static byte[] hexStringToByteArray(String s) {
int len = s.length();
byte[] data = new byte[len / 2];
for (int i = 0; i < len; i += 2) {
data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
+ Character.digit(s.charAt(i+1), 16));
}
return data;
}
}
cryptTest.java:
package nsdl.crypto;
import nsdl.crypto.BlockCrypt;
public class cryptTest {
public static void main (String args[]) {
if (args.length != 5) {
System.err.println("Usage: cryptTest (encrypt|decrypt) key iv algorithm mode");
System.err.println("Takes input from STDIN. Output goes to STDOUT.");
} else {
String operation = args[0];
String key = args[1];
String iv = args[2];
String algorithm = args[3];
String mode = args[4];
BlockCrypt blockCrypt = new BlockCrypt(key, iv, algorithm, mode);
if (operation.equalsIgnoreCase("encrypt")) {
blockCrypt.encrypt(System.in, System.out);
} else if (operation.equalsIgnoreCase("decrypt")) {
blockCrypt.decrypt(System.in, System.out);
} else {
System.err.println("Invalid operation. Use (encrypt|decrypt).");
}
}
}
}

The Cipher, ecipher, is not initialized, and it throws an IllegalStateException when you try to use it as if it were initialized in ENCRYPT_MODE.
Note your catch block in the constructor of BlockCrypt. It is catching an exception with no message, and printing "null" to System.err. Rather than aborting execution—perhaps by throwing an exception from the constructor—you keep sailing.
Replacing System.err.println(e.getMessage()) with e.printStackTrace() or at least System.err.println(e) should give you more detail. My guess is that ecipher.init() is throwing an exception because you're providing a 32-bit IV instead of 64 bits.

Perhaps looking at the source for javax.crypto.Cipher helps this make sense? I couldn't really figure it out, even finding the error message in the source. Good luck!