问题：
使用rsa密钥解密字符串
吕岳
java.lang.ArrayIndexOutOfBoundsException: too much data for RSA block
at com.android.org.bouncycastle.jcajce.provider.asymmetric.rsa.CipherSpi.engineDoFinal(CipherSpi.java:457)
at javax.crypto.Cipher.doFinal(Cipher.java:1204)
at com.benchmark.openssl.RSADecryption.decipherString(RSADecryption.java:295)
at com.benchmark.openssl.RSADecryption.main(RSADecryption.java:263)
at com.benchmark.MainActivity$1.onComplete(MainActivity.java:157)
at io.reactivex.internal.operators.completable.CompletableObserveOn$ObserveOnCompletableObserver.run(CompletableObserveOn.java:90)
at io.reactivex.Scheduler$DisposeTask.run(Scheduler.java:463)
at io.reactivex.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:66)
at io.reactivex.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:57)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:152)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:265)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:841)
openssl genrsa -out priv_key.pem 2048
openssl rsa -pubout -in priv_key.pem -out pub_key.pem
openssl rsautl -encrypt -in userdata.json -out user_encrypted_with_pub_key -inkey pub_key.pem –pubin
openssl rsautl -decrypt -in user_encrypted_with_pub_key -inkey priv_key.pem --> This is what I'm trying to do programmatically.
import org.spongycastle.util.io.pem.PemObject;
import org.spongycastle.util.io.pem.PemReader;
import android.util.Base64;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StringReader;
import java.security.GeneralSecurityException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Security;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
public static void main(String privateKeyPath, String encodedFilePath) throws FileNotFoundException,
IOException, NoSuchAlgorithmException, NoSuchProviderException {
Security.addProvider(new BouncyCastleProvider());
String encodedString = readFileAsString(encodedStringPath);
Timber.v("Encoded String: %s", encodedString);
KeyFactory factory = KeyFactory.getInstance("RSA", "BC");
try {
PrivateKey priv = generatePrivateKey(factory, privateKeyPath);
Timber.i(String.format("Instantiated private key: %s", priv));
decipherString(priv, encodedString);
} catch (InvalidKeySpecException e) {
e.printStackTrace();
}
}
private static PrivateKey generatePrivateKey(KeyFactory factory,
String filename) throws InvalidKeySpecException,
FileNotFoundException, IOException {
PemFile pemFile = new PemFile(filename, false);
byte[] content = pemFile.getPemObject().getContent();
PKCS8EncodedKeySpec privKeySpec = new PKCS8EncodedKeySpec(content);
return factory.generatePrivate(privKeySpec);
}
private static void decipherString(PrivateKey privateKey, String encodedStringData) {
byte[] dectyptedText = null;
try {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
dectyptedText = cipher.doFinal(encodedStringData.getBytes()); <---- EXCEPTION HERE
Timber.w("Deciphered text is: %s", new String(dectyptedText));
}
catch (Exception e) {
e.printStackTrace();
}
}
static class PemFile {
private PemObject pemObject;
public PemFile(String filename, boolean isBase64) throws FileNotFoundException, IOException {
PemReader pemReader = new PemReader(new InputStreamReader(new FileInputStream(filename)));
try {
this.pemObject = pemReader.readPemObject();
}
catch (Exception e) {
e.printStackTrace();
}
finally {
pemReader.close();
}
}
public PemObject getPemObject() {
return pemObject;
}
}
userData.json：
{
"username":"umer",
"password":"123456",
"pin" : "123"
}
共有1个答案
麹凯捷
由于我对OpenSSL的了解不多，所以我通过反复试验找到了答案。无论如何，解密加密文件的过程应该如下所示。
终端：
String -> (Encrypt) -> Encrypted String -> (convert to base64) -> EncryptedBase64EncodedString -> (Decrypt) -> Original String
在程序上：
EncryptedBase64EncodedString -> (convert from base64 to normal string [Use Default parameters only! No Padding or other constants for decoding base64 string]) -> Pass private_key & decoded string to Cipher -> Profit.
import org.spongycastle.util.io.pem.PemObject;
import org.spongycastle.util.io.pem.PemReader;
import android.util.Base64;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StringReader;
import java.security.GeneralSecurityException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Security;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.RSAPrivateCrtKeySpec;
import java.security.spec.X509EncodedKeySpec;
import javax.crypto.Cipher;
public static void main(String privateKeyPath, String publicKeyPath, String encodedStringPath, boolean isPublicKeyAndDataBase64) throws FileNotFoundException,
IOException, NoSuchAlgorithmException, NoSuchProviderException {
Security.addProvider(new BouncyCastleProvider());
String encodedString = readFileAsString(encodedStringPath);
if(isPublicKeyAndDataBase64) {
KeyFactory factory = KeyFactory.getInstance("RSA", "BC");
Timber.w("Encoded String converted from base64: %s", decodeBase64ToBytesa(encodedString));
try {
PrivateKey priv = generatePrivateKey(factory, privateKeyPath);
Timber.i(String.format("Instantiated private key: %s", priv));
decipherString(priv, decodeBase64ToBytesa(encodedString));
} catch (InvalidKeySpecException e) {
e.printStackTrace();
}
return;
}
else
Timber.w("Encoded String: %s", encodedString);
KeyFactory factory = KeyFactory.getInstance("RSA", "BC");
try {
PrivateKey priv = generatePrivateKey(factory, privateKeyPath);
Timber.i(String.format("Instantiated private key: %s", priv));
decipherString(priv, encodedString.getBytes());
PublicKey pub = generatePublicKey(factory, publicKeyPath);
Timber.i(String.format("Instantiated public key: %s", pub));
} catch (InvalidKeySpecException e) {
e.printStackTrace();
}
}
private static PrivateKey generatePrivateKey(KeyFactory factory,
String filename) throws InvalidKeySpecException,
FileNotFoundException, IOException {
PemFile pemFile = new PemFile(filename, false);
byte[] content = pemFile.getPemObject().getContent();
PKCS8EncodedKeySpec privKeySpec = new PKCS8EncodedKeySpec(content);
return factory.generatePrivate(privKeySpec);
}
private static PublicKey generatePublicKey(KeyFactory factory,
String filename) throws InvalidKeySpecException,
FileNotFoundException, IOException {
PemFile pemFile = new PemFile(filename, false);
byte[] content = pemFile.getPemObject().getContent();
X509EncodedKeySpec pubKeySpec = new X509EncodedKeySpec(content);
return factory.generatePublic(pubKeySpec);
}
private static void decipherString(PrivateKey privateKey, byte[] encodedStringData) {
byte[] dectyptedText = null;
try {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
dectyptedText = cipher.doFinal(encodedStringData);
Timber.w("Deciphered text is: %s", new String(dectyptedText));
}
catch (Exception e) {
e.printStackTrace();
}
}
static class PemFile {
private PemObject pemObject;
public PemFile(String filename, boolean isBase64) throws FileNotFoundException, IOException {
PemReader pemReader = null;
if(isBase64) {
Timber.i("reading base64 encoded pem file. base64DecodedString: %s", decodeBase64(filename));
pemReader = new PemReader(new StringReader(decodeBase64(filename)));
}
else
pemReader = new PemReader(new InputStreamReader(
new FileInputStream(filename)));
try {
this.pemObject = pemReader.readPemObject();
}
catch (Exception e) {
e.printStackTrace();
}finally {
pemReader.close();
}
}
public PemObject getPemObject() {
return pemObject;
}
}
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