问题
I am new to Java and was trying to use Hybrid cryptography using AES-128 Symmetric encryption and then RSA-1024 Asymmetric encryption on the generated symmetric key. Can someone help why I am getting this exception. I have already followed the other posts, and downloaded the Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files version 6 in the appropriate folder.
Code snippet:
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.security.Key;
import java.security.InvalidKeyException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Security;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;
import java.security.SecureRandom;
public class MainClass {
/**
* @param args
* Encryption and Decryption with AES/ECB/PKCS7Padding and RSA/ECB/PKCS1Padding
*/
public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
System.out.println("Enter a Message to be encrypted!");
// Read an input from console
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);
String s = br.readLine();
// Get the bytes of the input stream. Convert the input text
// to bytes.
byte[] input = s.getBytes("UTF8");
System.out.println("Input Message : " + new String(input));
// AES 128 bits Symmetric encryption of data
// Generate the AES key for Symmetric AES encryption
KeyGenerator kgenerator = KeyGenerator.getInstance("AES", "BC");
SecureRandom random = new SecureRandom();
kgenerator.init(128, random);
Key aeskey = kgenerator.generateKey();
byte[] raw = aeskey.getEncoded();
int sykLength = raw.toString().length();
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
System.out.println("Generated Symmetric Key :" + raw);
System.out.println("Generated Symmetric Key Length :" + sykLength);
System.out.println("Generated Key Length in Bytes: " + raw.length);
// Encrypt the data using AES cipher
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding", "BC");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] cipherText = new byte[cipher.getOutputSize(input.length)];
int ctLength = cipher.update(input, 0, input.length, cipherText, 0);
ctLength += cipher.doFinal(cipherText, ctLength);
System.out.println("Encrypted Message :" + new String(cipherText));
System.out.println("Encrypted Message Length: " + ctLength);
// RSA 1024 bits Asymmetric encryption of Symmetric AES key
// Generate Public and Private Keys (Can also use a certificate for keys)
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA", "BC");
kpg.initialize(1024, random);
KeyPair kpa = kpg.genKeyPair();
RSAPublicKey pubKey = (RSAPublicKey) kpa.getPublic();
RSAPrivateKey privKey = (RSAPrivateKey)kpa.getPrivate();
// Encrypt the generated Symmetric AES Key using RSA cipher
Cipher rsaCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", "BC");
rsaCipher.init(Cipher.ENCRYPT_MODE, pubKey);
byte[] rawRSA = raw.toString().getBytes("UTF8");
byte[] cipherTextRSA = new byte[rsaCipher.getOutputSize(rawRSA.length)];
int ctLengthRSA = rsaCipher.update(rawRSA, 0, rawRSA.length, cipherTextRSA, 0);
ctLengthRSA += rsaCipher.doFinal(cipherTextRSA, ctLengthRSA);
System.out.println("Encrypted Symmetric Key :" + cipherTextRSA);
System.out.println("Encrypted Symmetric Key Length :" + ctLengthRSA);
System.out.println("Encrypted Symmetric Key Length in Bytes: " + cipherTextRSA.length);
// RSA Decryption of Encrypted Symmetric AES key
rsaCipher.init(Cipher.DECRYPT_MODE, privKey);
byte[] plainTextRSA = new byte[rsaCipher.getOutputSize(ctLengthRSA)];
int ptLengthRSA = rsaCipher.update(cipherTextRSA, 0, ctLengthRSA, plainTextRSA, 0);
ptLengthRSA += rsaCipher.doFinal(plainTextRSA, ptLengthRSA);
SecretKeySpec DecrypskeySpec = new SecretKeySpec(plainTextRSA, "AES");
System.out.println("Decrypted Symmetric Key: " + new String(plainTextRSA));
System.out.println("Decrypted Symmetric Key Length: " + ptLengthRSA);
System.out.println( "Decrypted Symmetric Key Length in Bytes: " + plainTextRSA.length);
cipher.init(Cipher.DECRYPT_MODE, DecrypskeySpec, cipher.getParameters());
byte[] plainText = new byte[cipher.getOutputSize(ctLength)];
int ptLength = cipher.update(cipherText, 0, ctLength, plainText, 0);
ptLength += cipher.doFinal(plainText, ptLength);
System.out.println("Decrypted Message: " + new String(plainText));
System.out.println("Decrypted Message Length: " + ptLength);
System.out.println("Decrypted Message Length in Bytes: " + plainText.length);
}
}
Exception that I got:
Enter a Message to be encrypted!
test
Input Message : test
Generated Symmetric Key :[B@1c74f37
Generated Symmetric Key Length :10
Generated Key Length in Bytes: 16
Encrypted Message :ýÒSœW¶Þ34ÝGÝ
Encrypted Message Length: 16
Encrypted Symmetric Key :[B@1df280b
Encrypted Symmetric Key Length :128
Encrypted Symmetric Key Length in Bytes: 128
Decrypted Symmetric Key: [B@1c74f37 (Some symbols I got along with this decrypted key which I could not paste here)
Decrypted Symmetric Key Length in Bytes: 117
Exception in thread "main" java.security.InvalidKeyException: Key length not 128/192/256 bits.
at org.bouncycastle.jce.provider.JCEBlockCipher.engineInit(Unknown Source)
at org.bouncycastle.jce.provider.JCEBlockCipher.engineInit(Unknown Source)
at javax.crypto.Cipher.init(DashoA13*..)
at javax.crypto.Cipher.init(DashoA13*..)
at com.sap.srm.crpto.client.applet.MainClass.main(MainClass.java:99)
回答1:
Actually there are quite a few errors in your attempt to wrap and unwrap a symmetric key using asymmetric RSA, so I cleaned it up (I have no Bouncy Castle on my machine, so I used the default Sun providers, feel free to add "BC" where needed):
KeyGenerator kgenerator = KeyGenerator.getInstance("AES");
SecureRandom random = new SecureRandom();
kgenerator.init(128, random);
Key aeskey = kgenerator.generateKey();
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(1024, random);
KeyPair kpa = kpg.genKeyPair();
PublicKey pubKey = kpa.getPublic();
PrivateKey privKey = kpa.getPrivate();
// Encrypt the generated Symmetric AES Key using RSA cipher
Cipher rsaCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
rsaCipher.init(Cipher.WRAP_MODE, pubKey);
byte[] encryptedSymmKey = rsaCipher.wrap(aeskey);
// RSA Decryption of Encrypted Symmetric AES key
rsaCipher.init(Cipher.UNWRAP_MODE, privKey);
Key decryptedKey = rsaCipher.unwrap(encryptedSymmKey, "AES", Cipher.SECRET_KEY);
System.out.println("Decrypted Key Length: " + decryptedKey.getEncoded().length * 8); // -> 128
回答2:
Not an answer but easier to format code here, To help with debugging or checking the output, Use a hex conversion on the buffer before spitting it out in the logs. You can use something like this.
public static String asHex (byte buf[])
{
StringBuffer strbuf = new StringBuffer(buf.length * 2);
int i;
for (i = 0; i < buf.length; i++) {
if (((int) buf[i] & 0xff) < 0x10)
strbuf.append("0");
strbuf.append(Long.toString((int) buf[i] & 0xff, 16));
}
return strbuf.toString();
}
来源：https://stackoverflow.com/questions/6625776/java-security-invalidkeyexception-key-length-not-128-192-256-bits