I have an issue with my java code. I'm trying to encrypt a file. However, when I run my java code I get "java.security.InvalidKeyException: Invalid AES key length: 162 bytes".
Here is the code:
byte[] rawFile;
File f = new File("./src/wonkybox.stl");
FileInputStream fileReader = new FileInputStream(f);
rawFile = new byte[(int)f.length()];
fileReader.read(rawFile);
/***** Encrypt the file (CAN DO THIS ONCE!) ***********/
//Generate the public/private keys
KeyPairGenerator keyGen = KeyPairGenerator.getInstance("AES");
SecureRandom random = SecureRandom.getInstance("SHA1PRNG","SUN");
keyGen.initialize(1024, random);
KeyPair key = keyGen.generateKeyPair();
PrivateKey privKey = key.getPrivate();
PublicKey pubKey = key.getPublic();
//Store the keys
byte[] pkey = pubKey.getEncoded();
FileOutputStream keyfos = new FileOutputStream("./CloudStore/keys/pubkey");
keyfos.write(pkey);
keyfos.close();
pkey = privKey.getEncoded();
keyfos = new FileOutputStream("./CloudStore/keys/privkey");
keyfos.write(pkey);
keyfos.close();
//Read public/private keys
KeyFactory keyFactory = KeyFactory.getInstance("AES");
FileInputStream keyfis = new FileInputStream("./CloudStore/keys/pubkey");
byte[] encKey = new byte[keyfis.available()];
keyfis.read(encKey);
keyfis.close();
X509EncodedKeySpec pubKeySpec = new X509EncodedKeySpec(encKey);
PublicKey pub1Key = keyFactory.generatePublic(pubKeySpec);
keyfis = new FileInputStream("./CloudStore/keys/privkey");
encKey = new byte[keyfis.available()];
keyfis.read(encKey);
keyfis.close();
PKCS8EncodedKeySpec privKeySpec = new PKCS8EncodedKeySpec(encKey);
PrivateKey priv1key = keyFactory.generatePrivate(privKeySpec);
//Encrypt file using public key
Cipher cipher = Cipher.getInstance("AES");
System.out.println("provider= " + cipher.getProvider());
cipher.init(Cipher.ENCRYPT_MODE, pub1Key);
byte[] encryptedFile;
encryptedFile = cipher.doFinal(rawFile);
//Write encrypted file to 'CloudStore' folder
FileOutputStream fileEncryptOutput = new FileOutputStream(new File("./CloudStore/encrypted.txt"));
fileEncryptOutput.write(encryptedFile);
fileEncryptOutput.close();
The error occurs at the line "KeyPairGenerator keyGen = KeyPairGenerator.getInstance("AES");".
AES is a symmetric algorithm, hence they use of KeyPairGenerator is not supported. To generate a key with AES you call KeyGenerator
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(128); //set keysize, can be 128, 192, and 256
By looking at the rest of your code, it looks like you are trying to achive asymmetric encryption (since you call getPublic() and getPrivate() etc), so I advice you to switch to using RSA or any other asymmetric algorithm that java supports. You will most likley only need to replace AES with RSA in your getInstance(); calls, and pherhaps some fine-tuning. Good luck
As far as I know, AES is symmetric encryption algorithm i.e. it needs only one key for encryption/decryption.
From the JavaDoc of java.security.KeyPairGenerator:
The KeyPairGenerator class is used to generate pairs of public and private keys.
Meaning that it should be used for asymmetric encryption algorithms. For symmetric encryption algorithms one should use javax.crypto.KeyGenerator.
However, I advise simply mimicking some tutorial on how to encrypt / decrypt byte array in Java using AES like this one.
It uses sun.misc.Base64Encoder / Base64Decoder classes to encode / decode byte array to / from String, however you may skip this step.
Hope this helps
How can you use a keypair generator for AES? AES is a symmetric key algorithm. Refer this link. That means if you encrypt data using a key "k", then you will have to decrypt it also using the same key "k". But when you generate key pair, as the name suggests, two keys are generated and if you encrypt using one of the keys, you can decrypt only using the other key. This is the base for PKI.
If you want to use keypair generator use an algorithm like "rsa" or "dsa" in the getInstance() method like this :
KeyPairGenerator keygen=KeyPairGenerator.getInstance("rsa");
I think your code should now work fine after making the above change.
Related
I had generate public key using Java Spring Security, but I can not use that public key to encrypt the data using Nodejs crypto library. I think it is because of its format(X509).
My Nodejs code
module.exports.encryptRsa = (toEncrypt, pemPath) => {
let absolutePath = path.resolve(pemPath);
let publicKey = fs.readFileSync(absolutePath, "utf8");
let buffer = Buffer.from(toEncrypt);
let encrypted = crypto.publicEncrypt(publicKey, buffer);
return encrypted.toString("base64");
};
My Java code
KeyPairGenerator keyGen = KeyPairGenerator.getInstance(keyAlgorithm);
keyGen.initialize(2048);
KeyPair keyPair = keyGen.genKeyPair();
PrivateKey privateKey = keyPair.getPrivate();
PublicKey publicKey = keyPair.getPublic();
byte[] privateKeyBytes = privateKey.getEncoded();
byte[] publicKeyBytes = publicKey.getEncoded();
String formatPrivate = privateKey.getFormat(); // PKCS#8
String formatPublic = publicKey.getFormat(); // X.509
FileWriter fos = new FileWriter("publicKey.pem");
fos.write("-----BEGIN RSA PUBLIC KEY-----\n");
fos.write(enc.encodeToString(publicKeyBytes));
fos.write("\n-----END RSA PUBLIC KEY-----\n");
fos.close();
Java's getEncoded() method returns the public key in format called 'spki' by Node crypto. Java's name for that format is "X.509", an unfortunate choice because it causes confusion with certificates of that name.
The proper PEM header for spki keys is simply -----BEGIN PUBLIC KEY-----. Just get rid of RSA in the header and footer.
I have used the below OpenSSL code to do an AES encryption which is decrypting successfully in the Tax website
openssl rand 48 > 48byterandomvalue.bin
hexdump /bare 48byterandomvalue.bin > 48byterandomvalue.txt
set /a counter=0
for /f "tokens=* delims= " %%i in (48byterandomvalue.txt) do (
set /a counter=!counter!+1
set var=%%i
if "!counter!"=="1" (set aes1=%%i)
if "!counter!"=="2" (set aes2=%%i)
if "!counter!"=="3" (set iv=%%i)
)
set result1=%aes1:~0,50%
set result1=%result1: =%
set result2=%aes2:~0,50%
set result2=%result2: =%
set aeskey=%result1%%result2%
set initvector=%iv:~0,50%
set initvector=%initvector: =%
openssl aes-256-cbc -e -in PAYLOAD.zip -out PAYLOAD -K %aeskey% -iv %initvector%
openssl rsautl -encrypt -certin -inkey test_public.cer -in
48byterandomvalue.bin -out 000000.00000.TA.840_Key
But I wanted to do the same this in Java as part of migration, so i used the javax.crypto and java.security libraries but the decryption is failing when I upload the file on the Tax website
//creating the random AES-256 secret key
SecureRandom srandom = new SecureRandom();
KeyGenerator keyGen = KeyGenerator.getInstance("AES");
keyGen.init(256);
SecretKey secretKey = keyGen.generateKey();
byte[] aesKeyb = secretKey.getEncoded();
//creating the initialization vector
byte[] iv = new byte[128/8];
srandom.nextBytes(iv);
IvParameterSpec ivspec = new IvParameterSpec(iv);
byte[] encoded = Files.readAllBytes(Paths.get(filePath));
str = new String(encoded, StandardCharsets.US_ASCII);
//fetching the Public Key from certificate
FileInputStream fin = new FileInputStream("test_public.cer");
CertificateFactory f = CertificateFactory.getInstance("X.509");
X509Certificate certificate = (X509Certificate)f.generateCertificate(fin);
PublicKey pk = certificate.getPublicKey();
//encrypting the AES Key with Public Key
Cipher RSACipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
RSACipher.init(Cipher.ENCRYPT_MODE, pk);
byte[] RSAEncrypted = RSACipher.doFinal(aesKeyb);
FileOutputStream out = new FileOutputStream("000000.00000.TA.840_Key");
out.write(RSAEncrypted);
out.write(iv);
out.close();
Also, the AES key generated in java is different from the one generated via openssl. Can you guys please help.
EDIT 1:
Below is the code for AES Encrpytion used:
Cipher AESCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
AESCipher.init(Cipher.ENCRYPT_MODE, secretKey, ivspec);
byte[] AESEncrypted = AESCipher.doFinal(str.getBytes("UTF-8"));
String encryptedStr = new String(AESEncrypted);
The data that script and Java-code encrypt with RSA differ:
The script generates a random 48-bytes-sequence and stores it in the file 48byterandomvalue.bin. The first 32 bytes are used as AES key, the last 16 bytes as IV. Key and IV are used to encrypt the file PAYLOAD.zip with AES-256 in CBC-mode and store it as file PAYLOAD. The file 48byterandomvalue.bin is encrypted with RSA and stored as file 000000.00000.TA.840_Key.
In the Java-code, a random 32-bytes AES key and a random 16-bytes IV are generated. Both are used to perform the encryption with AES-256 in CBC-mode. The AES key is encrypted with RSA, concatenated with the unencrypted IV and the result is stored in the file 000000.00000.TA.840_Key.
The content of the file 000000.00000.TA.840_Key is different for script and Java-code. For the Java-code to generate the file 000000.00000.TA.840_Key with the script-logic, the unencrypted AES key must be concatenated with the unencrypted IV and this result must be encrypted with RSA:
...
//byte[] aesKeyb byte-array with random 32-bytes key
//byte[] iv byte-array with random 16-bytes iv
byte[] key_iv = new byte[aesKeyb.length + iv.length];
System.arraycopy(aesKeyb, 0, key_iv, 0, aesKeyb.length);
System.arraycopy(iv, 0, key_iv, aesKeyb.length, iv.length);
...
byte[] RSAEncrypted = RSACipher.doFinal(key_iv);
FileOutputStream out = new FileOutputStream("000000.00000.TA.840_Key");
out.write(RSAEncrypted);
out.close();
...
Note: The IV doesn't have to be secret and therefore doesn't need to be encrypted. The encryption is only necessary to generate the result of the script in the Java-code.
Another problem concerns the conversion of arbitrary binary data into strings. This generally leads to corrupted data if the encoding is unsuitable (e.g. ASCII or UTF8). Therefore
...
byte[] encoded = Files.readAllBytes(Paths.get(filePath));
str = new String(encoded, StandardCharsets.US_ASCII); // Doesn't work: ASCII (7-bit) unsuitable for arbitrary bytes, *
...
byte[] AESEncrypted = AESCipher.doFinal(str.getBytes("UTF-8")); // Doesn't work: UTF-8 unsuitable for arbitrary bytes and additionally different from *
String encryptedStr = new String(AESEncrypted); // Doesn't work: UTF-8 unsuitable for arbitrary bytes
...
should be replaced by
...
byte[] encoded = Files.readAllBytes(Paths.get(filePath));
...
byte[] AESEncrypted = AESCipher.doFinal(encoded);
FileOutputStream out = new FileOutputStream("PAYLOAD");
out.write(AESEncrypted);
out.close();
...
A suitable encoding to store arbitrary data in a string is e.g. Base64, but this isn't necessary in this case, because Base64-encoding isn't used in the script either.
Try these changes. If other issues occur, it would be best to test AES encryption, RSA encryption, and key_iv-generation separately. This makes it easier to isolate bugs.
I'm trying to use an asymmetric private and public key combination to generate a symmetric key for encrypting and decrypting some text, but, I'm stuck unable to use the generated key as it is 128bytes in size and this is unacceptable for the AES encryption. I'd like to solve this problem using just the JRE (no external libraries). Do you have a solution?
I've included my example code below, there's a comment indicating the line I get the exception thrown.
(encryptCipher.init(Cipher.ENCRYPT_MODE, tomSecretKeySpec, iv);)
I read about KDF hashing, but Java doesn't seem to have an obvious way of invoking this on my 128byte key. Also, Im not sure this is the right answer since my understanding is that the longer the key, the more secure the encryption (for a given algorithm). Perhaps I need to switch from using AES/CBC/PKCS5Padding, but none of the other algorithms included with the JDK as standard seem to support the 128byte key either.
public void demoSymmetricEncryption() throws NoSuchAlgorithmException, InvalidKeyException, NoSuchPaddingException, InvalidAlgorithmParameterException, UnsupportedEncodingException, IllegalBlockSizeException, BadPaddingException {
String keyAlgorithm = "DiffieHellman";
String keyAgreementAlgorithm = "DiffieHellman";
String keySpecAlgorithm = "AES";
String cipherAlgorithm = "AES/CBC/PKCS5Padding";
KeyPairGenerator keyGenerator = KeyPairGenerator.getInstance(keyAlgorithm);
keyGenerator.initialize(1024, new SecureRandom());
KeyPair tomKeyPair = keyGenerator.generateKeyPair();
PrivateKey tomPrivateKey = tomKeyPair.getPrivate();
PublicKey tomPublicKey = tomKeyPair.getPublic();
KeyPair steveKeyPair = keyGenerator.generateKeyPair();
PrivateKey stevePrivateKey = steveKeyPair.getPrivate();
PublicKey stevePublicKey = steveKeyPair.getPublic();
int maxKeyLen = Cipher.getMaxAllowedKeyLength("AES");
System.out.println("Limited encryption policy files installed : " + (maxKeyLen == 128)); // returns false
KeyAgreement tomKeyAgreement = KeyAgreement.getInstance(keyAgreementAlgorithm);
keyGenerator.initialize(1024, new SecureRandom());
tomKeyAgreement.init(tomPrivateKey);
tomKeyAgreement.doPhase(stevePublicKey, true);
byte[] tomSecret = tomKeyAgreement.generateSecret();
SecretKeySpec tomSecretKeySpec = new SecretKeySpec(tomSecret, keySpecAlgorithm);
KeyAgreement steveKeyAgreement = KeyAgreement.getInstance(keyAgreementAlgorithm);
steveKeyAgreement.init(stevePrivateKey);
steveKeyAgreement.doPhase(tomPublicKey, true);
byte[] steveSecret = steveKeyAgreement.generateSecret();
SecretKeySpec steveSecretKeySpec = new SecretKeySpec(steveSecret, keySpecAlgorithm);
System.out.println("Secret Keys are identical : " + steveSecretKeySpec.equals(tomSecretKeySpec)); // returns true
String initVector = "RandomInitVector";
Cipher encryptCipher = Cipher.getInstance(cipherAlgorithm);
IvParameterSpec iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
// fails because AES key is 128 bytes not 128 bits in length - think I need to use KDF hash to shrink it appropriately.
encryptCipher.init(Cipher.ENCRYPT_MODE, tomSecretKeySpec, iv);
// Attempt to use the cipher
byte[] encryptedData = encryptCipher.doFinal("Hello".getBytes());
Cipher decryptCipher = Cipher.getInstance(cipherAlgorithm);
iv = new IvParameterSpec(initVector.getBytes("UTF-8"));
decryptCipher.init(Cipher.DECRYPT_MODE, steveSecretKeySpec, iv);
byte[] decryptedData = decryptCipher.doFinal(encryptedData);
System.out.println("Decrypted Data : " + new String(decryptedData));
}
The output from the program is as follows:
Limited encryption policy files installed : false
Secret Keys are identical : true
Exception in thread "main" java.security.InvalidKeyException: Invalid AES key length: 128 bytes
at com.sun.crypto.provider.AESCrypt.init(AESCrypt.java:87)
at com.sun.crypto.provider.CipherBlockChaining.init(CipherBlockChaining.java:91)
at com.sun.crypto.provider.CipherCore.init(CipherCore.java:582)
at com.sun.crypto.provider.AESCipher.engineInit(AESCipher.java:339)
at javax.crypto.Cipher.implInit(Cipher.java:806)
at javax.crypto.Cipher.chooseProvider(Cipher.java:864)
at javax.crypto.Cipher.init(Cipher.java:1396)
at javax.crypto.Cipher.init(Cipher.java:1327)
at crypto.SymetricEncryptionTest.demoSymmetricEncryption(SymetricEncryptionTest.java:76)
at crypto.SymetricEncryptionTest.main(SymetricEncryptionTest.java:29)
The error is: * Invalid AES key length: 128 bytes*
Valid AES key sizes are 128-bits, 192-bits and 256-bits or in bytes: 16-bytes, 24-bytes and 32-bytes.
Use an AES key size that is valid.
The general method of generation a symmetric key is just to get the bytes from a cryptographic PRNG. For Java see Class SecureRandom.
For key derivation use PBKDF2, see Class SecretKeyFactory and Java Cryptography Architecture Standard Algorithm Name Documentation "PBKDF2WithHmacSHA1" (Constructs secret keys using the Password-Based Key Derivation Function function).
For an example see OWASP Hashing Java but use "PBKDF2WithHmacSHA1" as the algorithm.
The reason the code wasn't working was that I was using incompatible algorithms. The corrections are as follows:
Replace lines:
String keyAlgorithm = "DiffieHellman";
String keyAgreementAlgorithm = "DiffieHellman";
with
String keyAlgorithm = "EC";
String keyAgreementAlgorithm = "ECDH";
int keySize = 128;
and replace lines
keyGenerator.initialize(1024, new SecureRandom());
with
keyGenerator.initialize(keySize, new SecureRandom());
Program now produces output:
Limited encryption policy files installed : false
Secret Keys are identical : true
Decrypted Data : Hello
Technically, you probably also want to Base64 encode the encrypted output and then decode it again prior to the decode as below:
String encryptedData = Base64.encode(encryptCipher.doFinal("Hello".getBytes()));
byte[] decryptedData = decryptCipher.doFinal(Base64.decode(encryptedData));
I've been strugling with reading a publickey file which I want to get the key sting in the file and use it to encrypt another file. I'm using RSA PKCS1 v1.5 in encrypting and signing the file with SH1 hashing algorythim but thats not the problem, the problem is that I've been supplied with the publickey file to use when encrypting and I cant seem to win with reading the file and generating a publicKey object.
Here's the code:
void setPublicKey(String file)
{
try
{
FileInputStream keyfis = new FileInputStream(file);
byte[] encKey = new byte[keyfis.available()]; keyfis.read(encKey);
keyfis.close();
X509EncodedKeySpec pubKeySpec = new X509EncodedKeySpec(encKey);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
// I get an exception on the below line
publicKey = keyFactory.generatePublic(pubKeySpec);
} catch (Exception e)
{
e.printStackTrace();
}
}
Can someone please help!!
AFAIK X509 encoded keys are binary files encoded using ASN.1. Therefore the question on new-lines at the end does not make any sense.
If you have a text file you have a PEM encoded file and I am currently not sure which KeySpec you have to use in this case.
You may convert the PEM encoded key to a DER encoded key (e.g. using OpenSSL) or you can use BouncyCastle which as support for loading PEM encoded keys.
BTW: Using keyfis.read(encKey); is dangerous as the read method only reads up encKey bytes but don't have to. Better create a DataInputStream from the InputStream and use readFully(encKey):
new DataInputStream(keyfis).readFully(encKey);
Found the solution but not sure yet if its the right solution coz I still have to get the PrivateKey and decrypt the file but for now I was able to encrypt it using the supplied PublicKey as the modulus but I don’t have the exponent and I just used some common number “65537” as the exponent
Which I read that it is not a critical part of the encryption.
I had to change the logic to use the RSAPublicKeySpec (which uses BigInteger and Base64Decoder)instead of X509EncodedKeySpec to set the KeySpec
And continue to use the KeyFactory object to generate the public key.
Now this logic NEEDS the modulus and exponent.
byte[] buffer = new byte[(int) new File(file).length()];
BufferedInputStream f = new BufferedInputStream(new FileInputStream(file));
f.read(buffer);
String modulusBase64 = new String(buffer);
BASE64Decoder b64dec = new BASE64Decoder();
String exponentBase64 = "65537";
RSAPublicKeySpec publicKeySpec = new RSAPublicKeySpec(new BigInteger (1, b64dec.decodeBuffer(modulusBase64)), new BigInteger(1, b64dec.decodeBuffer(exponentBase64)));
KeyFactory publicKeyFactory = KeyFactory.getInstance("RSA");
publicKey = publicKeyFactory.generatePublic(publicKeySpec);
//This is the PublicKey in the file. "J45t4SWGbFzeNuunHliNDZcLVeFU7lOpyNkX1xX+sVNaVJK8Cr0rSjUkDC8h9n+Zg7m0MVYk0byafPycmzWNDynpvj2go9mXwmUpmcQprX1vexxT5j1XmAaBZFYaJRcPWSVU92pdNh1Sd3USdFjgH0LQ5B3s8F95xdyc/5I5LDKhRobx6c1gUs/rnJfJjAgynrE4AsNsNem+STaZWjeb4J+f5Egy9xTSEl6UWxCClgCwhXopy10cBlH8CucpP0cyckOCIOloJ7mEMRCIpp6HPpYexVmXXSikTXh7aQ7tSlTMwUziIERc/zRpyj1Nk96Y7V8AorLFrn1R4Of66mpAdQ=="
I want to generate a privatekey PKCS8 format encrypted with password, and I try with this code:
String password = "123456";
KeyPairGenerator gen = KeyPairGenerator.getInstance("RSA");
gen.initialize(2048);
KeyPair key = gen.generateKeyPair();
PrivateKey privateKey = key.getPrivate();
PublicKey publicKey = key.getPublic();
FileOutputStream pvt = new FileOutputStream("d:\\pvt123456.der");
try {
pvt.write(privateKey.getEncoded());
pvt.flush();
} finally {
pvt.close();
}
FileOutputStream pub = new FileOutputStream("d:\\pub123456.der");
try {
pub.write(publicKey.getEncoded());
pub.flush();
} finally {
pub.close();
}
But I don´t know how to encrypt a password with 3des to be compatible with openssl format.
I know it's a little bit late but I also have been looking for a way to do this and while i was searching I found your question, now that I have found a way to do this I decided to come back and share this:
// generate key pair
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(1024);
KeyPair keyPair = keyPairGenerator.genKeyPair();
// extract the encoded private key, this is an unencrypted PKCS#8 private key
byte[] encodedprivkey = keyPair.getPrivate().getEncoded();
// We must use a PasswordBasedEncryption algorithm in order to encrypt the private key, you may use any common algorithm supported by openssl, you can check them in the openssl documentation http://www.openssl.org/docs/apps/pkcs8.html
String MYPBEALG = "PBEWithSHA1AndDESede";
String password = "pleaseChangeit!";
int count = 20;// hash iteration count
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(encodedprivkey);
// Now construct PKCS #8 EncryptedPrivateKeyInfo object
AlgorithmParameters algparms = AlgorithmParameters.getInstance(MYPBEALG);
algparms.init(pbeParamSpec);
EncryptedPrivateKeyInfo encinfo = new EncryptedPrivateKeyInfo(algparms, ciphertext);
// and here we have it! a DER encoded PKCS#8 encrypted key!
byte[] encryptedPkcs8 = encinfo.getEncoded();
This example code is based on the folowing code I found: http://www.jensign.com/JavaScience/PEM/EncPrivKeyInfo/EncPrivKeyInfo.java
but the folowing resource also helped me to understand a little bit better: http://java.sun.com/j2se/1.4.2/docs/guide/security/jce/JCERefGuide.html