I have a very annoying problem with the unreliable encryption and decryption of string with the RSA algorithm in Java. It seams to only work about 35% of the times, and I can't figure out why it sometimes does work and sometimes don't. Here's some test-code I wrote to try to verify the randomness in the encryption/decryption. It runs 100 laps and it encrypts and decrypts the same string every time and prints the number of times it was successful:
public static void main(String[] args) throws Exception {
byte[] dataToEncrypt = "Hello World!".getBytes("UTF-16LE");
byte[] cipherData = null;
byte[] decryptedData;
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(512);
KeyPair kp = kpg.genKeyPair();
Key publicKey = kp.getPublic();
Key privateKey = kp.getPrivate();
KeyFactory fact = KeyFactory.getInstance("RSA");
RSAPublicKeySpec pub = (RSAPublicKeySpec) fact.getKeySpec(publicKey,
RSAPublicKeySpec.class);
RSAPublicKeySpec spec = new RSAPublicKeySpec(pub.getModulus(), pub
.getPublicExponent());
KeyFactory factory = KeyFactory.getInstance("RSA");
PublicKey publicKeyRSA = factory.generatePublic(spec);
Cipher cipher = Cipher.getInstance("RSA");
int k = 0;
for (int i = 0; i < 100; i++) {
try {
cipher.init(Cipher.ENCRYPT_MODE, publicKeyRSA);
cipherData = cipher.doFinal(dataToEncrypt);
} catch (Exception e1) {
System.out.println("Encrypt error");
}
String s = new String(cipherData, "UTF-16LE");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
try {
decryptedData = cipher.doFinal(s.getBytes("UTF-16LE"));
System.out.println("Decrypted: "
+ new String(decryptedData, "UTF-16LE"));
k += 1;
} catch (Exception e1) {
System.out.println("Decrypt error");
}
}
System.out.println("Number of correct decryptions is: " + k);
}
I've tried to initialize the KeyPairGenerator with various values without any success.
Edit: Now it works like a charm, thanks to Base64 :
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PublicKey;
import java.security.spec.RSAPublicKeySpec;
import javax.crypto.Cipher;
public class Test {
public static void main(String[] args) throws Exception {
byte[] dataToEncrypt = "Hello World!".getBytes("UTF-16LE");
byte[] cipherData = null;
byte[] decryptedData;
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(512);
KeyPair kp = kpg.genKeyPair();
Key publicKey = kp.getPublic();
Key privateKey = kp.getPrivate();
KeyFactory fact = KeyFactory.getInstance("RSA");
RSAPublicKeySpec pub = (RSAPublicKeySpec) fact.getKeySpec(publicKey,
RSAPublicKeySpec.class);
RSAPublicKeySpec spec = new RSAPublicKeySpec(pub.getModulus(), pub
.getPublicExponent());
KeyFactory factory = KeyFactory.getInstance("RSA");
PublicKey publicKeyRSA = factory.generatePublic(spec);
Cipher cipher = Cipher.getInstance("RSA");
int k = 0;
for (int i = 0; i < 100; i++) {
try {
cipher.init(Cipher.ENCRYPT_MODE, publicKeyRSA);
cipherData = cipher.doFinal(dataToEncrypt);
} catch (Exception e1) {
System.out.println("Encrypt error");
}
String s = Base64.encodeBytes(cipherData);
cipher.init(Cipher.DECRYPT_MODE, privateKey);
try {
decryptedData = cipher.doFinal(Base64.decode(s));
System.out.println("Decrypted: "
+ new String(decryptedData, "UTF-16LE"));
k += 1;
} catch (Exception e1) {
System.out.println("Decrypt error");
}
}
System.out.println("Number of correct decryptions is: " + k);
}
}
This is the problem, or at least a problem:
String s = new String(cipherData, "UTF-16LE");
You're taking arbitrary binary data and trying to create a string from it, treating it as if it's UTF-16-encoded text. It's not. It's arbitrary binary data.
Either keep it in binary form (as byte[]
) or use base64 to convert it to text in a safe, reversible manner. ( This public domain base64 encoder has a reasonable API, for example.)
可能是因为您将加密的字节流转换为UTF16-LE,这是您不应该做的。
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.