I'm trying to encrypt & decrypt password and for these generating key so far so good.Now I need to store this key in properties file but when I add the key it look like this :
#Tue Nov 01 08:22:52 EET 2016
KEY=\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000
So I suspect from my code maybe something wrong ?!?!
And there is a part of my code =
private byte[] key = new byte[16];
public void addProperties(String x, String z) {
Properties properties = new Properties();
String propertiesFileName = "config.properties";
try {
OutputStream out = new FileOutputStream(propertiesFileName);
properties.setProperty(x, z);
properties.store(out, null);
} catch (IOException e) {
e.printStackTrace();
}
}
public void generateKey() {
KeyGenerator keygen;
SecretKey secretKey;
byte[] keybyte = new byte[64];
try {
keygen = KeyGenerator.getInstance("AES");
keygen.init(128);
secretKey = keygen.generateKey();
keybyte = secretKey.getEncoded();
key = keybyte;
//THIS METHOD ADDING PROP TO PROPERTIES FILE
addProperties("KEY", new String(key));
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
}
Thanks for help.All answers acceptable.
KeyGenerator#generateKey() has return type of SecretKey and from javadocs
Keys that implement this interface return the string RAW as their
encoding format (see getFormat), and return the raw key bytes as the
result of a getEncoded method call. (The getFormat and getEncoded
methods are inherited from the java.security.Key parent interface.)
So you need to convert them and there is already asked question on this
String encodedKey = Base64.getEncoder().encodeToString(secretKey.getEncoded());
SecretKey originalKey = new SecretKeySpec(decodedKey, 0, decodedKey.length, "AES");
Related
I have the following code for encrypt
public static String encrypt(String value, char[] secret) {
try {
final byte[] bytes = value != null ? value.getBytes(StandardCharsets.UTF_8) : new byte[0];
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
SecretKey key = keyFactory.generateSecret(new PBEKeySpec(secret));
Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
pbeCipher.init(Cipher.ENCRYPT_MODE, key, new PBEParameterSpec(IsoGame.$().crossPlatformManager.getCrossPlatformUtilsInstance().getDeviceUniqueIdentifier().getBytes(StandardCharsets.UTF_8), 20));
return new String(Base64.encodeBase64(pbeCipher.doFinal(bytes)), StandardCharsets.UTF_8);
} catch (Exception e) {
e.printStackTrace();
}
return value;
}
and the following code for decrypt.
public static String decrypt(String value, char[] secret) {
try {
final byte[] bytes = value != null ? Base64.decodeBase64(value.getBytes(StandardCharsets.UTF_8)) : new byte[0];
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
SecretKey key = keyFactory.generateSecret(new PBEKeySpec(secret));
Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
pbeCipher.init(Cipher.DECRYPT_MODE, key, new PBEParameterSpec(IsoGame.$().crossPlatformManager.getCrossPlatformUtilsInstance().getDeviceUniqueIdentifier().getBytes(StandardCharsets.UTF_8), 20));
return new String(pbeCipher.doFinal(bytes), StandardCharsets.UTF_8);
} catch (Exception e) {
e.printStackTrace();
}
return value;
}
However, sometimes the exception is being thrown at
pbeCipher.doFinal(bytes)
in decrypt method.
The exception is javax.crypto.BadPaddingException: pad block corrupted
It's strange, as I'm getting this exception sometimes with the same values .
Any ideas?
Thanks.
The most likely reason would simply be the wrong password to be supplied. If the wrong password is supplied then the wrong key is derived. Then the ciphertext will be decrypted to garbage plaintext. This will only be noticed if the padding exception gets thrown: unpadding random bytes is likely to fail.
You could e.g. first validate that the derived key is correct by performing a HMAC over known data using the derived key. In addition, it would be a good idea to use some kind of authenticated encryption, so that if the key or data is wrong or corrupted that decryption does indeed fail. If you're unlucky then - at this time - the data will decrypt, unpadding will succeed and you end up with garbage plaintext.
Of course, you'd better upgrade to PBKDF2 for key derivation, and upgrade AES to e.g. AES-GCM instead of DES. Currently your encryption is entirely insecure, even if you use a strong password.
Your problem is
IsoGame.$().crossPlatformManager.getCrossPlatformUtilsInstance().getDeviceUniqueIdentifier().getBytes(StandardCharsets.UTF_8)
I have ran the following code multiple times and no exception occurred and the decrypted data was equal to "Hello there!":
public static void main(String[] args)
{
new CryptographyError();
}
private CryptographyError()
{
char[] secret = "MySecret".toCharArray();
String mesasge = "Hello there!";
EncryptedData encryptedData = encrypt(mesasge, secret);
System.out.println("ENCRYPTED " + encryptedData.encryptedString);
String decrypted = decrypt(encryptedData, secret);
System.out.println("DECRYPTED " + decrypted);
}
private static final SecureRandom RANDOM = new SecureRandom();
public static EncryptedData encrypt(String value, char[] secret) {
try {
final byte[] bytes = value != null ? value.getBytes(StandardCharsets.UTF_8) : new byte[0];
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
SecretKey key = keyFactory.generateSecret(new PBEKeySpec(secret));
Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
byte[] salt = new byte[8];
RANDOM.nextBytes(salt);
pbeCipher.init(Cipher.ENCRYPT_MODE, key, new PBEParameterSpec(salt, 20));
return new EncryptedData(salt, new String(Base64.getEncoder().encode(pbeCipher.doFinal(bytes)), StandardCharsets.UTF_8));
} catch (Exception e) {
e.printStackTrace();
System.out.println(value);
}
return null;
}
public static String decrypt(EncryptedData encryptedData, char[] secret) {
try {
String value = encryptedData.encryptedString;
byte[] salt = encryptedData.salt;
final byte[] bytes = value != null ? Base64.getDecoder().decode(value.getBytes(StandardCharsets.UTF_8)) : new byte[0];
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
SecretKey key = keyFactory.generateSecret(new PBEKeySpec(secret));
Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
pbeCipher.init(Cipher.DECRYPT_MODE, key, new PBEParameterSpec(salt, 20));
return new String(pbeCipher.doFinal(bytes), StandardCharsets.UTF_8);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
private static class EncryptedData
{
private final byte[] salt;
private final String encryptedString;
private EncryptedData(byte[] salt, String encryptedString)
{
this.salt = salt;
this.encryptedString = encryptedString;
}
}
The only main difference between my code and your code is
IsoGame.$().crossPlatformManager.getCrossPlatformUtilsInstance().getDeviceUniqueIdentifier().getBytes(StandardCharsets.UTF_8)
which means that must not return the same value on encryption and decryption.
Also if you want to test this you can just change the salt between them and notice the exception is thrown again.
Also Maarten Bodewes gave you some good notes about how to improve your code.
I am trying to read a password based encrypted private key from a file, but I'm getting the following exception:
java.io.IOException: DerInputStream.getLength(): lengthTag=109, too big.
at sun.security.util.DerInputStream.getLength(DerInputStream.java:561)
at sun.security.util.DerValue.init(DerValue.java:365)
at sun.security.util.DerValue.<init>(DerValue.java:294)
at javax.crypto.EncryptedPrivateKeyInfo.<init>(EncryptedPrivateKeyInfo.java:84) ...
This is how I encrypt and write to file the private key:
public static void savePrivateKeyToDisk(PrivateKey privateKey, String passord){
try {
// unencrypted PKCS#8 private key
byte[] encodedPrivateKey = privateKey.getEncoded();
String MYPBEALG = "PBEWithSHA1AndDESede";
int count = 20;
SecureRandom random = new SecureRandom();
byte[] salt = new byte[8];
random.nextBytes(salt);
// Create PBE parameter set
PBEParameterSpec pbeParamSpec = new PBEParameterSpec(salt, count);
PBEKeySpec pbeKeySpec = new PBEKeySpec(password.toCharArray());
SecretKeyFactory keyFac = SecretKeyFactory.getInstance(MYPBEALG);
SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);
Cipher pbeCipher = Cipher.getInstance(MYPBEALG);
// Initialize PBE Cipher with key and parameters
pbeCipher.init(Cipher.ENCRYPT_MODE, pbeKey, pbeParamSpec);
// Encrypt the encoded Private Key with the PBE key
byte[] cipherText = pbeCipher.doFinal(encodedPrivateKey);
// Now construct PKCS #8 EncryptedPrivateKeyInfo object
AlgorithmParameters algparms = AlgorithmParameters.getInstance(MYPBEALG);
algparms.init(pbeParamSpec);
EncryptedPrivateKeyInfo encinfo = new EncryptedPrivateKeyInfo(algparms, cipherText);
// DER encoded PKCS#8 encrypted key
byte[] encryptedPkcs8 = encinfo.getEncoded();
File encryptedPrivate = new File(PRIVATE_KEY_FILE);
if (encryptedPrivate.getParentFile() != null) {
encryptedPrivate.getParentFile().mkdirs();
}
encryptedPrivate.createNewFile();
ObjectOutputStream publicKeyOS = new ObjectOutputStream(
new FileOutputStream(encryptedPrivate));
publicKeyOS.writeObject(encryptedPkcs8);
publicKeyOS.close();
}
catch (Exception e){
e.printStackTrace();
}
}
... and this is how I'm trying to read the encrypted private key:
public static PrivateKey getPrivateKey(String passwd){
try {
byte[] encodedPrivateKey = getFileBytes(PRIVATE_KEY_FILE);
// exception thrown from here
EncryptedPrivateKeyInfo encryptPKInfo = new EncryptedPrivateKeyInfo(encodedPrivateKey);
Cipher cipher = Cipher.getInstance(encryptPKInfo.getAlgName());
PBEKeySpec pbeKeySpec = new PBEKeySpec(passwd.toCharArray());
SecretKeyFactory secFac = SecretKeyFactory.getInstance(encryptPKInfo.getAlgName());
Key pbeKey = secFac.generateSecret(pbeKeySpec);
AlgorithmParameters algParams = encryptPKInfo.getAlgParameters();
cipher.init(Cipher.DECRYPT_MODE, pbeKey, algParams);
KeySpec pkcs8KeySpec = encryptPKInfo.getKeySpec(cipher);
KeyFactory kf = KeyFactory.getInstance(ALGORITHM);
return kf.generatePrivate(pkcs8KeySpec);
}
catch (Exception e){
e.printStackTrace();
return null;
}
}
... the getFileBytes method:
private static byte[] getFileBytes(String infile){
File f = new File(infile) ;
int sizecontent = ((int) f.length());
byte[] data = new byte[sizecontent];
try
{
FileInputStream freader = new FileInputStream(f);
freader.read(data, 0, sizecontent) ;
freader.close();
return data;
}
catch(IOException ioe)
{
System.out.println(ioe.toString());
return null;
}
}
It seems like the encrypted private key is not in the right format, but I save it in DER PKCS#8 format.
So, the question: What is the mistake in this code?
I guess the problem is that you write an Object, but then you read byte[] (not an Object)
I would suggest that you either read the whole object and then get the required bytes or even better write byte[] directly (don't use ObjectOutputStream) and then load these bytes, eg:
FileOutputStream fos = new FileOutputStream(PRIVATE_KEY_FILE);
fos.write(myByteArray);
fos.close();
and then to retrieve it:
byte[] bytes = Files.readAllBytes(Paths.get(PRIVATE_KEY_FILE));
I have the following code,
public static String encrypt(String plainText, String key){
try{
PublicKey publicKey = KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(Base64.decode(key, Base64.DEFAULT)));
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
return Base64.encodeToString(cipher.doFinal(plainText.getBytes("UTF-8")),Base64.DEFAULT);
}catch (Exception e) {
e.printStackTrace();
}
return null;
}
I want to convert this to C#. I have tried CryptUtils but it doesn't work https://github.com/ServiceStack/ServiceStack/blob/master/src/ServiceStack.Common/CryptUtils.cs
Sample key,
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ9AMIIBCgKCAQEAoqB1N9kugk4UKYnbh0fcg3qYyYKP0m4B
MjWd05ReeAdj+7JRYDEKO6xthDdVSdRO1/2V+YtY8DnXWnxRaICwu8235s3imZCyqgYnomPWdY+F
K540oTz/zug+9wbrlzt/WQFUU4lPlQbzm/Gjw8XfaCozT0e3bnWQcD7rORCOyuJgwSGgREjTv1ss
pgEaKTMknii9vpGZLeAXwoeIYROhuT4IoIkPDhtY0/UZiCi6v7Ja2dmy53VlWIkcm3rcnSJdvpXr
OgiHvaNABHmeymNycNqd6WUaysBRheluQ86nq/2nZPW0gcvmYt5zbMMYX3yY/n2WtAKeNQBAEW1q
b0s6MwIDAQAB
Possible encryped value,
Y3VTjghDnTrCeG8C/RklKsJ3Y0Mt89sSGGin28E4iQPQvKqeZBws7rBQEZaRamDWftxCkEYZs4Qh
V2l4IVlrawdtRmQlcQh8McrpqP/97Gz8pEDEYnqA7kqBTqZw0Z5o0WsshGSwiAQ9wNSym4xHejkq
zrKxWP8XCMkcT0NlKlRMoqKKICFKZbqWeSQkQM5y9OEcmB6inNNkJCoM1Ip48+cK3cOE6dqXNVrl
sSTZ8WQKwoB3dJmcYqexR3kAvBYdX6ZxEF+2+6b9h8+tc5G7Y5R2eqycyUossdkCcI3fNVhyc72P
axCjZFWZUgfDGCxg1WNhStrH9L8c59P35JKKug==
Since i don't have the private key, i can't decrypt, but at least this produces the right lengthed values.
So try this (you need bouncycastle for reading pem):
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Security;
var keyBytes =
Convert.FromBase64String(
"MIIBI...."); // your key here
AsymmetricKeyParameter asymmetricKeyParameter = PublicKeyFactory.CreateKey(keyBytes);
RsaKeyParameters rsaKeyParameters = (RsaKeyParameters)asymmetricKeyParameter;
RSAParameters rsaParameters = new RSAParameters();
rsaParameters.Modulus = rsaKeyParameters.Modulus.ToByteArrayUnsigned();
rsaParameters.Exponent = rsaKeyParameters.Exponent.ToByteArrayUnsigned();
RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
rsa.ImportParameters(rsaParameters);
byte[] plaintext = Encoding.UTF8.GetBytes("amount=1¤cy=AED");
byte[] ciphertext = rsa.Encrypt(plaintext, false);
string cipherresult = Convert.ToBase64String(ciphertext);
I am first going to describe the problem which I have, and then give some background to what I am trying to do. Finally I shall paste some relevant code snippets.
I am trying to implement secret key encryption/decryption using the method specified in https://stackoverflow.com/a/992413/171993. If I use that example as-is, it works (although I did notice that I need to re-instantiate the Cipher class, otherwise the decryption produces garbage). However, in my implementation I get the following exception:
java.security.InvalidKeyException: Wrong algorithm: AES or Rijndael required
at com.sun.crypto.provider.AESCrypt.init(AESCrypt.java:77)
at com.sun.crypto.provider.CipherBlockChaining.init(CipherBlockChaining.java:91)
at com.sun.crypto.provider.CipherCore.init(CipherCore.java:469)
at com.sun.crypto.provider.AESCipher.engineInit(AESCipher.java:217)
at javax.crypto.Cipher.implInit(Cipher.java:790)
at javax.crypto.Cipher.chooseProvider(Cipher.java:848)
at javax.crypto.Cipher.init(Cipher.java:1347)
at javax.crypto.Cipher.init(Cipher.java:1281)
at securitytest.SecurityManager.getCipher(SecurityManager.java:175)
at securitytest.SecurityManager.decryptSecretKey(SecurityManager.java:379)
at securitytest.SecurityManager.<init>(SecurityManager.java:82)
at securitytest.Test.main(Test.java:44)
To beat off the obvious question, yes, I do use the same algorithm: in fact, I assigned AES/CBC/PKCS5Padding to a constant and use that for instantiating both the Cipher class for encryption and decryption. I have also tried using only AES instantiate Cipher for the decryption, but that did not work either.
What I am trying to do is to password-protect a secret key by using AES/CBC/PKCS5Padding. I generate a random salt and initialisation vector. After encrypting the secret key, I append the initialisation vector (an array of bytes) to the encrypted value (also an array of bytes, creating a new array). I then encode this value in Base64 and store it in a Sqlite database, along with the salt (which, for the sake of simplicity, I store as a comma-separated string of values). However when I try to decrypt, I get the above exception. I can verify that directly after my call to the encryption method and directly before the decryption method, the following values are exactly the same (when converted to Base64 so that I can print it out):
The salt
The initialisation vector
The encrypted secret key (i.e. the cipher text)
I have tried both Java 6 and 7: both give the same results. I have also ruled out the unlimited strength jurisdiction policy files as an issue. In fact, I get a similar error if I substitute "AES" with another algorithm and adjust the length of the salt accordingly (for example "Blowfish" with IV length 8, which produces java.security.InvalidKeyException: Wrong algorithm: Blowfish required).
Google has not been able to help me with this problem. If anyone can shed some light on this, I would be very appreciative.
Here are some code snippets (my apologies, it is a little rough):
private static final int INIT_VECTOR_LENGTH = 16;
private static final int PRIVATE_KEY_LENGTH = 128;
private static final int SALT_LENGTH = 16;
private static final int PBE_KEYSPEC_ITERATIONS = 65536;
private static final String CIPHER_ALGORITHM = "AES";
private static final String CIPHER_ALGORITHM_MODE = "CBC";
private static final String CIPHER_ALGORITHM_PADDING = "PKCS5Padding";
private static final String DIGEST = "SHA1";
private static final String PLAINTEXT_ENCODING = "UTF8";
private static final String PRNG = DIGEST + "PRNG";
private static final String SECRET_KEY_FACTORY = "PBKDF2WithHmac" + DIGEST;
private static final String CIPHER = CIPHER_ALGORITHM + "/" + CIPHER_ALGORITHM_MODE + "/" + CIPHER_ALGORITHM_PADDING;
private IvParameterSpec ivSpec;
private final BASE64Encoder encoder = new BASE64Encoder();
private final BASE64Decoder decoder = new BASE64Decoder();
private Cipher getCipher(SecretKey key, int mode) {
Cipher cipher = null;
try {
cipher = Cipher.getInstance(CIPHER);
}
catch (NoSuchAlgorithmException e) {System.err.println(System.err.println(e.getMessage());}
catch (NoSuchPaddingException e) {System.err.println(e.getMessage());}
try {
if (mode == Cipher.ENCRYPT_MODE) {
cipher.init(mode, key);
AlgorithmParameters params = cipher.getParameters();
ivSpec = params.getParameterSpec(IvParameterSpec.class);
}
else {
/* This is my point-of-failure. */
cipher.init(mode, key, ivSpec);
}
}
catch (InvalidKeyException e) {System.err.println(e.getMessage());}
catch (InvalidAlgorithmParameterException e) {System.err.println(e.getMessage());}
catch (InvalidParameterSpecException e) {System.err.println(e.getMessage());}
return cipher;
}
private SecurityData.Secrets generateSecrets(SecretKey decryptedKey, byte[] salt, String passphrase) {
/* Generate a new key for encrypting the secret key. */
byte[] raw = null;
PBEKey key = null;
PBEKeySpec password = new PBEKeySpec(passphrase.toCharArray(), salt, PBE_KEYSPEC_ITERATIONS, PRIVATE_KEY_LENGTH);
SecretKeyFactory factory = null;
byte[] initVector = null;
byte[] secretKeyBytes = decryptedKey.getEncoded();
try {
factory = SecretKeyFactory.getInstance(SECRET_KEY_FACTORY);
key = (PBEKey) factory.generateSecret(password);
}
catch (NoSuchAlgorithmException e) {System.err.println(e.getMessage());}
catch (InvalidKeySpecException e) {System.err.println(e.getMessage());}
SecretKeySpec newKey = new SecretKeySpec(key.getEncoded(), CIPHER_ALGORITHM);
/* Encrypt the secret key. */
IvParameterSpec ivSpec = new IvParameterSpec(initVector);
Cipher cipher = getCipher(newKey, ivSpec, Cipher.ENCRYPT_MODE);
try {
raw = cipher.doFinal(secretKeyBytes);
}
catch (IllegalBlockSizeException e) {System.err.println(e.getMessage());}
catch (BadPaddingException e) {System.err.println(e.getMessage());}
return new SecurityData.Secrets(encoder.encode(concatByteArrays(initVector, raw)), joinByteArray(salt));
}
private SecretKey decryptSecretKey(String encryptedKey, String salt, String passphrase) {
/* Get initialisation vector. */
byte[] raw = null, decoded = null, initVector = new byte[INIT_VECTOR_LENGTH];
try {
decoded = decoder.decodeBuffer(encryptedKey);
} catch (IOException e) {System.err.println(e.getMessage());}
System.arraycopy(decoded, 0, initVector, 0, INIT_VECTOR_LENGTH);
raw = new byte[decoded.length-INIT_VECTOR_LENGTH];
System.arraycopy(decoded, INIT_VECTOR_LENGTH, raw, 0, decoded.length-INIT_VECTOR_LENGTH);
IvParameterSpec ivSpec = new IvParameterSpec(initVector);
/* Generate the key. */
byte[] rawSalt = splitByteArrayString(salt);
PBEKeySpec password = new PBEKeySpec(passphrase.toCharArray(), rawSalt, PBE_KEYSPEC_ITERATIONS, PRIVATE_KEY_LENGTH);
SecretKeyFactory factory = null;
PBEKey key = null;
try {
factory = SecretKeyFactory.getInstance(SECRET_KEY_FACTORY);
key = (PBEKey) factory.generateSecret(password);
}
catch (NoSuchAlgorithmException e) {System.err.println(e.getMessage());}
catch (InvalidKeySpecException e) {System.err.println(e.getMessage());}
Cipher cipher = getCipher(key, Cipher.DECRYPT_MODE);
/* Decrypt the message. */
byte[] stringBytes = null;
try {
stringBytes = cipher.doFinal(raw);
}
catch (IllegalBlockSizeException e) {System.err.println(e.getMessage());}
catch (BadPaddingException e) {System.err.println(e.getMessage());}
/* Converts the decoded message to a String. */
String clear = null;
try {
clear = new String(stringBytes, PLAINTEXT_ENCODING);
}
catch (UnsupportedEncodingException e) {System.err.println(e.getMessage());}
return new SecretKeySpec(clear.getBytes(), CIPHER_ALGORITHM);
}
The SecretKey object needs to return "AES" from its getAlgorithm() method. That's why the example has these steps:
SecretKey tmp = factory.generateSecret(spec);
SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES");
I want to convert String to secretKey
public void generateCode(String keyStr){
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(128); // 192 and 256 bits may not be available
// Generate the secret key specs.
secretKey skey=keyStr; //How can I make the casting here
//SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
}
I try to use BASE64Decoder instead of secretKey, but I face a problem which is I cannot specify key length.
EDIT:
I want to call this function from another place
static public String encrypt(String message , String key , int keyLength) throws Exception {
// Get the KeyGenerator
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(keyLength); // 192 and 256 bits may not be available
// Generate the secret key specs.
SecretKey skey = key; //here is the error
byte[] raw = skey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
// Instantiate the cipher
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
System.out.println("msg is" + message + "\n raw is" + raw);
byte[] encrypted = cipher.doFinal(message.getBytes());
String cryptedValue = new String(encrypted);
System.out.println("encrypted string: " + cryptedValue);
return cryptedValue;
}
If anybody could help, I'd be very thankful.
No integrity checks, for these particular reasons
The need is not apparent from the use case.
"AES/GCM/NoPadding" mode is only available from Java 7 onward
It depends on the user if they want to deploy e.g. HMAC and/or AESCMAC (recommended).
It would require an additional key at the minimum, and two full passes.
If you got an implementation of GCM mode at both sides - e.g. using Bouncy Castle on Java 6 - please go for it, as it is much more secure (as long as the "IV" is really unique). It should be really easy to change the implementation.
Implementation notes regarding encryption
This implementation is not safe when used in an unrestricted client / server role because of padding oracle attacks (they require 128 tries per byte or lower, on average, independent of algorithm or key size). You will need to use a MAC, HMAC or Signature over the encrypted data, and verify it before decrypting to deploy it in client/server mode.
Decrypt will return null if decryption fails. This can only indicate a padding exception, which should be adequately handled (did I warn about padding oracle attacks?)
Invalid keys will be returned as InvalidArgumentException.
All other security related exceptions are "swept under the table" as it means that the Java runtime environment is invalid. For example, supporting "UTF-8" and "AES/CBC/PKCS5Padding" is required for every Java SE implementation.
Some other notes
Please don't try the opposite and insert bytes directly into the input string of the encrypt method (using new String(byte[]) for instance). The method may fail silently!
Optimized for readability. Go for Base64 stream and CipherStream implementations if you rather prefer speed and better memory footprint.
You need at least Java 6 SE or compatible to run this code.
Encryption/decryption may fail for AES key sizes over 128 bit as you may need policy files for unrestricted encryption (available from Oracle)
Beware of governmental regulations when exporting encryption.
This implementation uses hex keys instead of base64 keys as they are small enough, and hex is just easier to edit/verify manually.
Used hex and base64 encoding/decoding retrieved from the JDK, no external libraries needed whatsoever.
Uber simple to use, but of course not very object oriented, no caching of object instances used in encrypt/decrypt. Refactor at will.
OK, here comes some code...
public static String encrypt(final String plainMessage,
final String symKeyHex) {
final byte[] symKeyData = DatatypeConverter.parseHexBinary(symKeyHex);
final byte[] encodedMessage = plainMessage.getBytes(Charset
.forName("UTF-8"));
try {
final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
final int blockSize = cipher.getBlockSize();
// create the key
final SecretKeySpec symKey = new SecretKeySpec(symKeyData, "AES");
// generate random IV using block size (possibly create a method for
// this)
final byte[] ivData = new byte[blockSize];
final SecureRandom rnd = SecureRandom.getInstance("SHA1PRNG");
rnd.nextBytes(ivData);
final IvParameterSpec iv = new IvParameterSpec(ivData);
cipher.init(Cipher.ENCRYPT_MODE, symKey, iv);
final byte[] encryptedMessage = cipher.doFinal(encodedMessage);
// concatenate IV and encrypted message
final byte[] ivAndEncryptedMessage = new byte[ivData.length
+ encryptedMessage.length];
System.arraycopy(ivData, 0, ivAndEncryptedMessage, 0, blockSize);
System.arraycopy(encryptedMessage, 0, ivAndEncryptedMessage,
blockSize, encryptedMessage.length);
final String ivAndEncryptedMessageBase64 = DatatypeConverter
.printBase64Binary(ivAndEncryptedMessage);
return ivAndEncryptedMessageBase64;
} catch (InvalidKeyException e) {
throw new IllegalArgumentException(
"key argument does not contain a valid AES key");
} catch (GeneralSecurityException e) {
throw new IllegalStateException(
"Unexpected exception during encryption", e);
}
}
public static String decrypt(final String ivAndEncryptedMessageBase64,
final String symKeyHex) {
final byte[] symKeyData = DatatypeConverter.parseHexBinary(symKeyHex);
final byte[] ivAndEncryptedMessage = DatatypeConverter
.parseBase64Binary(ivAndEncryptedMessageBase64);
try {
final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
final int blockSize = cipher.getBlockSize();
// create the key
final SecretKeySpec symKey = new SecretKeySpec(symKeyData, "AES");
// retrieve random IV from start of the received message
final byte[] ivData = new byte[blockSize];
System.arraycopy(ivAndEncryptedMessage, 0, ivData, 0, blockSize);
final IvParameterSpec iv = new IvParameterSpec(ivData);
// retrieve the encrypted message itself
final byte[] encryptedMessage = new byte[ivAndEncryptedMessage.length
- blockSize];
System.arraycopy(ivAndEncryptedMessage, blockSize,
encryptedMessage, 0, encryptedMessage.length);
cipher.init(Cipher.DECRYPT_MODE, symKey, iv);
final byte[] encodedMessage = cipher.doFinal(encryptedMessage);
// concatenate IV and encrypted message
final String message = new String(encodedMessage,
Charset.forName("UTF-8"));
return message;
} catch (InvalidKeyException e) {
throw new IllegalArgumentException(
"key argument does not contain a valid AES key");
} catch (BadPaddingException e) {
// you'd better know about padding oracle attacks
return null;
} catch (GeneralSecurityException e) {
throw new IllegalStateException(
"Unexpected exception during decryption", e);
}
}
Usage:
String plain = "Zaphod's just zis guy, ya knöw?";
String encrypted = encrypt(plain, "000102030405060708090A0B0C0D0E0F");
System.out.println(encrypted);
String decrypted = decrypt(encrypted, "000102030405060708090A0B0C0D0E0F");
if (decrypted != null && decrypted.equals(plain)) {
System.out.println("Hey! " + decrypted);
} else {
System.out.println("Bummer!");
}
Here's the version using Base64 Util class instead of DatatypeConverter
public static String encrypt(final String plainMessage,
final String symKeyHex) {
final byte[] symKeyData = Base64.decode(symKeyHex,Base64.DEFAULT);
final byte[] encodedMessage = plainMessage.getBytes(Charset
.forName("UTF-8"));
try {
final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
final int blockSize = cipher.getBlockSize();
// create the key
final SecretKeySpec symKey = new SecretKeySpec(symKeyData, "AES");
// generate random IV using block size (possibly create a method for
// this)
final byte[] ivData = new byte[blockSize];
final SecureRandom rnd = SecureRandom.getInstance("SHA1PRNG");
rnd.nextBytes(ivData);
final IvParameterSpec iv = new IvParameterSpec(ivData);
cipher.init(Cipher.ENCRYPT_MODE, symKey, iv);
final byte[] encryptedMessage = cipher.doFinal(encodedMessage);
// concatenate IV and encrypted message
final byte[] ivAndEncryptedMessage = new byte[ivData.length
+ encryptedMessage.length];
System.arraycopy(ivData, 0, ivAndEncryptedMessage, 0, blockSize);
System.arraycopy(encryptedMessage, 0, ivAndEncryptedMessage,
blockSize, encryptedMessage.length);
final String ivAndEncryptedMessageBase64 = Base64.encodeToString(ivAndEncryptedMessage,Base64.DEFAULT);
return ivAndEncryptedMessageBase64;
} catch (InvalidKeyException e) {
throw new IllegalArgumentException(
"key argument does not contain a valid AES key");
} catch (GeneralSecurityException e) {
throw new IllegalStateException(
"Unexpected exception during encryption", e);
}
}
public static String decrypt(final String ivAndEncryptedMessageBase64,
final String symKeyHex) {
final byte[] symKeyData = Base64.decode((symKeyHex),Base64.DEFAULT);
final byte[] ivAndEncryptedMessage = Base64.decode(ivAndEncryptedMessageBase64,Base64.DEFAULT);
try {
final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
final int blockSize = cipher.getBlockSize();
// create the key
final SecretKeySpec symKey = new SecretKeySpec(symKeyData, "AES");
// retrieve random IV from start of the received message
final byte[] ivData = new byte[blockSize];
System.arraycopy(ivAndEncryptedMessage, 0, ivData, 0, blockSize);
final IvParameterSpec iv = new IvParameterSpec(ivData);
// retrieve the encrypted message itself
final byte[] encryptedMessage = new byte[ivAndEncryptedMessage.length
- blockSize];
System.arraycopy(ivAndEncryptedMessage, blockSize,
encryptedMessage, 0, encryptedMessage.length);
cipher.init(Cipher.DECRYPT_MODE, symKey, iv);
final byte[] encodedMessage = cipher.doFinal(encryptedMessage);
// concatenate IV and encrypted message
final String message = new String(encodedMessage,
Charset.forName("UTF-8"));
return message;
} catch (InvalidKeyException e) {
throw new IllegalArgumentException(
"key argument does not contain a valid AES key");
} catch (BadPaddingException e) {
// you'd better know about padding oracle attacks
return null;
} catch (GeneralSecurityException e) {
throw new IllegalStateException(
"Unexpected exception during decryption", e);
}
}
Just a reminder for those who get a Padding exception. Make sure you are using the correct Key length. Hint: look at Maarten's post: his hex is exactly 32 ;) That's no coincidence :)