我正在使用一个需要对文件系统上的文件进行加密（然后解密）的Android应用程序。我编写了一个android测试来测试在网上找到的代码，并根据需要进行调整。我尝试加密一个简单的文本，然后尝试对其解密。问题是，当我尝试对其进行解密时，要加密/解密的内容的开头出现了一些奇怪的字符。例如，我尝试对这样的字符串进行加密/解密：
Concentration - Programming Music 0100 (Part 4)Concentration - Programming Music 0100 (Part 4)Concentration - Programming Music 0100 (Part 4)Concentration - Programming Music 0100 (Part 4)Concentration - Programming Music 0100 (Part 4)Concentration - Programming Music 0100 (Part 4)Concentration - Programming Music 0100 (Part 4)
我收到了
X��YK�P���$BProgramming Music 0100 (Part 4)Concentration - Programming Music 0100 (Part 4)Concentration - Programming Music 0100 (Part 4)Concentration - Programming Music 0100 (Part 4)Concentration - Programming Music 0100 (Part 4)Concentration - Programming Music 0100 (Part 4)Concentration - Programming Music 0100 (Part 4)
测试代码为
@Test
public void test() throws IOException, GeneralSecurityException {
String input = "Concentration - Programming Music 0100 (Part 4)";
for (int i=0;i<10;i++) {
input+=input;
}
String password = EncryptSystem.encrypt(new ByteArrayInputStream(input.getBytes(Charset.forName("UTF-8"))), new File(this.context.getFilesDir(), "test.txt"));
InputStream inputStream = EncryptSystem.decrypt(password, new File(this.context.getFilesDir(), "test.txt"));
//creating an InputStreamReader object
InputStreamReader isReader = new InputStreamReader(inputStream, Charset.forName("UTF-8"));
//Creating a BufferedReader object
BufferedReader reader = new BufferedReader(isReader);
StringBuilder sb = new StringBuilder();
String str;
while ((str = reader.readLine()) != null) {
sb.append(str);
}
System.out.println(sb.toString());
Assert.assertEquals(input, sb.toString());
}
课程代码是：
import android.os.Build;
import android.os.Process;
import android.util.Base64;
import android.util.Log;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.security.*;
import java.util.Arrays;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicBoolean;
import javax.crypto.*;
public class EncryptSystem {
public static class SecretKeys {
private SecretKey confidentialityKey;
private byte[] iv;
/**
* An aes key derived from a base64 encoded key. This does not generate the
* key. It's not random or a PBE key.
*
* @param keysStr a base64 encoded AES key / hmac key as base64(aesKey) : base64(hmacKey).
* @return an AES and HMAC key set suitable for other functions.
*/
public static SecretKeys of(String keysStr) throws InvalidKeyException {
String[] keysArr = keysStr.split(":");
if (keysArr.length != 2) {
throw new IllegalArgumentException("Cannot parse aesKey:iv");
} else {
byte[] confidentialityKey = Base64.decode(keysArr[0], BASE64_FLAGS);
if (confidentialityKey.length != AES_KEY_LENGTH_BITS / 8) {
throw new InvalidKeyException("Base64 decoded key is not " + AES_KEY_LENGTH_BITS + " bytes");
}
byte[] iv = Base64.decode(keysArr[1], BASE64_FLAGS);
/* if (iv.length != HMAC_KEY_LENGTH_BITS / 8) {
throw new InvalidKeyException("Base64 decoded key is not " + HMAC_KEY_LENGTH_BITS + " bytes");
}*/
return new SecretKeys(
new SecretKeySpec(confidentialityKey, 0, confidentialityKey.length, CIPHER),
iv);
}
}
public SecretKeys(SecretKey confidentialityKeyIn, byte[] i) {
setConfidentialityKey(confidentialityKeyIn);
iv = new byte[i.length];
System.arraycopy(i, 0, iv, 0, i.length);
}
public SecretKey getConfidentialityKey() {
return confidentialityKey;
}
public void setConfidentialityKey(SecretKey confidentialityKey) {
this.confidentialityKey = confidentialityKey;
}
@Override
public String toString() {
return Base64.encodeToString(getConfidentialityKey().getEncoded(), BASE64_FLAGS)
+ ":" + Base64.encodeToString(this.iv, BASE64_FLAGS);
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
SecretKeys that = (SecretKeys) o;
return confidentialityKey.equals(that.confidentialityKey) &&
Arrays.equals(iv, that.iv);
}
@Override
public int hashCode() {
int result = Objects.hash(confidentialityKey);
result = 31 * result + Arrays.hashCode(iv);
return result;
}
public byte[] getIv() {
return this.iv;
}
}
// If the PRNG fix would not succeed for some reason, we normally will throw an exception.
// If ALLOW_BROKEN_PRNG is true, however, we will simply log instead.
private static final boolean ALLOW_BROKEN_PRNG = false;
private static final String CIPHER_TRANSFORMATION = "AES/CBC/PKCS5Padding";
private static final String CIPHER = "AES";
private static final int AES_KEY_LENGTH_BITS = 128;
private static final int IV_LENGTH_BYTES = 16;
private static final int PBE_ITERATION_COUNT = 10000;
private static final int PBE_SALT_LENGTH_BITS = AES_KEY_LENGTH_BITS; // same size as key output
private static final String PBE_ALGORITHM = "PBKDF2WithHmacSHA1";
//Made BASE_64_FLAGS public as it's useful to know for compatibility.
public static final int BASE64_FLAGS = Base64.NO_WRAP;
//default for testing
static final AtomicBoolean prngFixed = new AtomicBoolean(false);
private static final String HMAC_ALGORITHM = "HmacSHA256";
private static final int HMAC_KEY_LENGTH_BITS = 256;
public static SecretKeys generateKey() throws GeneralSecurityException {
fixPrng();
KeyGenerator keyGen = KeyGenerator.getInstance(CIPHER);
// No need to provide a SecureRandom or set a seed since that will
// happen automatically.
keyGen.init(AES_KEY_LENGTH_BITS);
SecretKey confidentialityKey = keyGen.generateKey();
return new SecretKeys(confidentialityKey, generateIv());
}
private static void fixPrng() {
if (!prngFixed.get()) {
synchronized (PrngFixes.class) {
if (!prngFixed.get()) {
PrngFixes.apply();
prngFixed.set(true);
}
}
}
}
private static byte[] randomBytes(int length) throws GeneralSecurityException {
fixPrng();
SecureRandom random = new SecureRandom();
byte[] b = new byte[length];
random.nextBytes(b);
return b;
}
private static byte[] generateIv() throws GeneralSecurityException {
return randomBytes(IV_LENGTH_BYTES);
}
private static String keyString(SecretKeys keys) {
return keys.toString();
}
public static SecretKeys generateKeyFromPassword(String password, byte[] salt) throws GeneralSecurityException {
fixPrng();
//Get enough random bytes for both the AES key and the HMAC key:
KeySpec keySpec = new PBEKeySpec(password.toCharArray(), salt,
PBE_ITERATION_COUNT, AES_KEY_LENGTH_BITS + HMAC_KEY_LENGTH_BITS);
SecretKeyFactory keyFactory = SecretKeyFactory
.getInstance(PBE_ALGORITHM);
byte[] keyBytes = keyFactory.generateSecret(keySpec).getEncoded();
// Split the random bytes into two parts:
byte[] confidentialityKeyBytes = copyOfRange(keyBytes, 0, AES_KEY_LENGTH_BITS / 8);
byte[] integrityKeyBytes = copyOfRange(keyBytes, AES_KEY_LENGTH_BITS / 8, AES_KEY_LENGTH_BITS / 8 + HMAC_KEY_LENGTH_BITS / 8);
//Generate the AES key
SecretKey confidentialityKey = new SecretKeySpec(confidentialityKeyBytes, CIPHER);
return new SecretKeys(confidentialityKey, generateIv());
}
private static byte[] copyOfRange(byte[] from, int start, int end) {
int length = end - start;
byte[] result = new byte[length];
System.arraycopy(from, start, result, 0, length);
return result;
}
public static SecretKeys generateKeyFromPassword(String password, String salt) throws GeneralSecurityException {
return generateKeyFromPassword(password, Base64.decode(salt, BASE64_FLAGS));
}
public static String encrypt(InputStream inputStream, File fileToWrite)
throws GeneralSecurityException {
SecretKeys secretKeys = generateKey();
return encrypt(inputStream, secretKeys, fileToWrite);
}
public static InputStream decrypt(String secretKey, File fileToRead) throws InvalidKeyException, NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterException, FileNotFoundException {
SecretKeys secretKeys = SecretKeys.of(secretKey);
Cipher aesCipherForDecryption = Cipher.getInstance(CIPHER_TRANSFORMATION);
aesCipherForDecryption.init(Cipher.DECRYPT_MODE, secretKeys.getConfidentialityKey(),
new IvParameterSpec(secretKeys.getIv()));
return new CipherInputStream(new FileInputStream(fileToRead), aesCipherForDecryption);
}
private static String encrypt(InputStream inputStream, SecretKeys secretKeys, File fileToWrite)
throws GeneralSecurityException {
byte[] iv = generateIv();
Cipher aesCipherForEncryption = Cipher.getInstance(CIPHER_TRANSFORMATION);
aesCipherForEncryption.init(Cipher.ENCRYPT_MODE, secretKeys.getConfidentialityKey(), new IvParameterSpec(iv));
saveFile(inputStream, aesCipherForEncryption, fileToWrite);
/*
* Now we get back the IV that will actually be used. Some Android
* versions do funny stuff w/ the IV, so this is to work around bugs:
*/
/*iv = aesCipherForEncryption.getIV();
//byte[] byteCipherText = aesCipherForEncryption.doFinal(plaintext);
byte[] ivCipherConcat = CipherTextIvMac.ivCipherConcat(iv, byteCipherText);
byte[] integrityMac = generateMac(ivCipherConcat, secretKeys.getIntegrityKey());
return new CipherTextIvMac(byteCipherText, iv, integrityMac);*/
return secretKeys.toString();
}
private static boolean saveFile(InputStream inputStream, Cipher aesCipherForEncryption, File fileToWrite) {
try {
OutputStream outputStream = null;
try {
byte[] fileReader = new byte[4096];
/*long fileSize = body.contentLength();*/
long fileSizeDownloaded = 0;
outputStream = new CipherOutputStream(new FileOutputStream(fileToWrite), aesCipherForEncryption);
while (true) {
int read = inputStream.read(fileReader);
if (read == -1) {
break;
}
outputStream.write(fileReader, 0, read);
fileSizeDownloaded += read;
}
outputStream.flush();
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
} finally {
if (inputStream != null) {
inputStream.close();
}
if (outputStream != null) {
outputStream.close();
}
}
} catch (IOException e) {
return false;
}
}
public static final class PrngFixes {
private static final int VERSION_CODE_JELLY_BEAN = 16;
private static final int VERSION_CODE_JELLY_BEAN_MR2 = 18;
private static final byte[] BUILD_FINGERPRINT_AND_DEVICE_SERIAL = getBuildFingerprintAndDeviceSerial();
/**
* Hidden constructor to prevent instantiation.
*/
private PrngFixes() {
}
/**
* Applies all fixes.
*
* @throws SecurityException if a fix is needed but could not be
* applied.
*/
public static void apply() {
applyOpenSSLFix();
installLinuxPRNGSecureRandom();
}
/**
* Applies the fix for OpenSSL PRNG having low entropy. Does nothing if
* the fix is not needed.
*
* @throws SecurityException if the fix is needed but could not be
* applied.
*/
private static void applyOpenSSLFix() throws SecurityException {
if ((Build.VERSION.SDK_INT < VERSION_CODE_JELLY_BEAN)
|| (Build.VERSION.SDK_INT > VERSION_CODE_JELLY_BEAN_MR2)) {
// No need to apply the fix
return;
}
try {
// Mix in the device- and invocation-specific seed.
Class.forName("org.apache.harmony.xnet.provider.jsse.NativeCrypto")
.getMethod("RAND_seed", byte[].class).invoke(null, generateSeed());
// Mix output of Linux PRNG into OpenSSL's PRNG
int bytesRead = (Integer) Class
.forName("org.apache.harmony.xnet.provider.jsse.NativeCrypto")
.getMethod("RAND_load_file", String.class, long.class)
.invoke(null, "/dev/urandom", 1024);
if (bytesRead != 1024) {
throw new IOException("Unexpected number of bytes read from Linux PRNG: "
+ bytesRead);
}
} catch (Exception e) {
if (ALLOW_BROKEN_PRNG) {
Log.w(PrngFixes.class.getSimpleName(), "Failed to seed OpenSSL PRNG", e);
} else {
throw new SecurityException("Failed to seed OpenSSL PRNG", e);
}
}
}
/**
* Installs a Linux PRNG-backed {@code SecureRandom} implementation as
* the default. Does nothing if the implementation is already the
* default or if there is not need to install the implementation.
*
* @throws SecurityException if the fix is needed but could not be
* applied.
*/
private static void installLinuxPRNGSecureRandom() throws SecurityException {
if (Build.VERSION.SDK_INT > VERSION_CODE_JELLY_BEAN_MR2) {
// No need to apply the fix
return;
}
// Install a Linux PRNG-based SecureRandom implementation as the
// default, if not yet installed.
Provider[] secureRandomProviders = Security.getProviders("SecureRandom.SHA1PRNG");
// Insert and check the provider atomically.
// The official Android Java libraries use synchronized methods for
// insertProviderAt, etc., so synchronizing on the class should
// make things more stable, and prevent race conditions with other
// versions of this code.
synchronized (java.security.Security.class) {
if ((secureRandomProviders == null)
|| (secureRandomProviders.length < 1)
|| (!secureRandomProviders[0].getClass().getSimpleName().equals("LinuxPRNGSecureRandomProvider"))) {
Security.insertProviderAt(new PrngFixes.LinuxPRNGSecureRandomProvider(), 1);
}
// Assert that new SecureRandom() and
// SecureRandom.getInstance("SHA1PRNG") return a SecureRandom backed
// by the Linux PRNG-based SecureRandom implementation.
SecureRandom rng1 = new SecureRandom();
if (!rng1.getProvider().getClass().getSimpleName().equals("LinuxPRNGSecureRandomProvider")) {
if (ALLOW_BROKEN_PRNG) {
Log.w(PrngFixes.class.getSimpleName(),
"new SecureRandom() backed by wrong Provider: " + rng1.getProvider().getClass());
return;
} else {
throw new SecurityException("new SecureRandom() backed by wrong Provider: "
+ rng1.getProvider().getClass());
}
}
SecureRandom rng2 = null;
try {
rng2 = SecureRandom.getInstance("SHA1PRNG");
} catch (NoSuchAlgorithmException e) {
if (ALLOW_BROKEN_PRNG) {
Log.w(PrngFixes.class.getSimpleName(), "SHA1PRNG not available", e);
return;
} else {
new SecurityException("SHA1PRNG not available", e);
}
}
if (!rng2.getProvider().getClass().getSimpleName().equals("LinuxPRNGSecureRandomProvider")) {
if (ALLOW_BROKEN_PRNG) {
Log.w(PrngFixes.class.getSimpleName(),
"SecureRandom.getInstance(\"SHA1PRNG\") backed by wrong" + " Provider: "
+ rng2.getProvider().getClass());
return;
} else {
throw new SecurityException(
"SecureRandom.getInstance(\"SHA1PRNG\") backed by wrong" + " Provider: "
+ rng2.getProvider().getClass());
}
}
}
}
/**
* {@code Provider} of {@code SecureRandom} engines which pass through
* all requests to the Linux PRNG.
*/
private static class LinuxPRNGSecureRandomProvider extends Provider {
public LinuxPRNGSecureRandomProvider() {
super("LinuxPRNG", 1.0, "A Linux-specific random number provider that uses"
+ " /dev/urandom");
// Although /dev/urandom is not a SHA-1 PRNG, some apps
// explicitly request a SHA1PRNG SecureRandom and we thus need
// to prevent them from getting the default implementation whose
// output may have low entropy.
put("SecureRandom.SHA1PRNG", PrngFixes.LinuxPRNGSecureRandom.class.getName());
put("SecureRandom.SHA1PRNG ImplementedIn", "Software");
}
}
/**
* {@link SecureRandomSpi} which passes all requests to the Linux PRNG (
* {@code /dev/urandom}).
*/
public static class LinuxPRNGSecureRandom extends SecureRandomSpi {
/*
* IMPLEMENTATION NOTE: Requests to generate bytes and to mix in a
* seed are passed through to the Linux PRNG (/dev/urandom).
* Instances of this class seed themselves by mixing in the current
* time, PID, UID, build fingerprint, and hardware serial number
* (where available) into Linux PRNG.
*
* Concurrency: Read requests to the underlying Linux PRNG are
* serialized (on sLock) to ensure that multiple threads do not get
* duplicated PRNG output.
*/
private static final File URANDOM_FILE = new File("/dev/urandom");
private static final Object sLock = new Object();
/**
* Input stream for reading from Linux PRNG or {@code null} if not
* yet opened.
*
* @GuardedBy("sLock")
*/
private static DataInputStream sUrandomIn;
/**
* Output stream for writing to Linux PRNG or {@code null} if not
* yet opened.
*
* @GuardedBy("sLock")
*/
private static OutputStream sUrandomOut;
/**
* Whether this engine instance has been seeded. This is needed
* because each instance needs to seed itself if the client does not
* explicitly seed it.
*/
private boolean mSeeded;
@Override
protected void engineSetSeed(byte[] bytes) {
try {
OutputStream out;
synchronized (sLock) {
out = getUrandomOutputStream();
}
out.write(bytes);
out.flush();
} catch (IOException e) {
// On a small fraction of devices /dev/urandom is not
// writable Log and ignore.
Log.w(PrngFixes.class.getSimpleName(), "Failed to mix seed into "
+ URANDOM_FILE);
} finally {
mSeeded = true;
}
}
@Override
protected void engineNextBytes(byte[] bytes) {
if (!mSeeded) {
// Mix in the device- and invocation-specific seed.
engineSetSeed(generateSeed());
}
try {
DataInputStream in;
synchronized (sLock) {
in = getUrandomInputStream();
}
synchronized (in) {
in.readFully(bytes);
}
} catch (IOException e) {
throw new SecurityException("Failed to read from " + URANDOM_FILE, e);
}
}
@Override
protected byte[] engineGenerateSeed(int size) {
byte[] seed = new byte[size];
engineNextBytes(seed);
return seed;
}
private DataInputStream getUrandomInputStream() {
synchronized (sLock) {
if (sUrandomIn == null) {
// NOTE: Consider inserting a BufferedInputStream
// between DataInputStream and FileInputStream if you need
// higher PRNG output performance and can live with future PRNG
// output being pulled into this process prematurely.
try {
sUrandomIn = new DataInputStream(new FileInputStream(URANDOM_FILE));
} catch (IOException e) {
throw new SecurityException("Failed to open " + URANDOM_FILE
+ " for reading", e);
}
}
return sUrandomIn;
}
}
private OutputStream getUrandomOutputStream() throws IOException {
synchronized (sLock) {
if (sUrandomOut == null) {
sUrandomOut = new FileOutputStream(URANDOM_FILE);
}
return sUrandomOut;
}
}
}
/**
* Generates a device- and invocation-specific seed to be mixed into the
* Linux PRNG.
*/
private static byte[] generateSeed() {
try {
ByteArrayOutputStream seedBuffer = new ByteArrayOutputStream();
DataOutputStream seedBufferOut = new DataOutputStream(seedBuffer);
seedBufferOut.writeLong(System.currentTimeMillis());
seedBufferOut.writeLong(System.nanoTime());
seedBufferOut.writeInt(Process.myPid());
seedBufferOut.writeInt(Process.myUid());
seedBufferOut.write(BUILD_FINGERPRINT_AND_DEVICE_SERIAL);
seedBufferOut.close();
return seedBuffer.toByteArray();
} catch (IOException e) {
throw new SecurityException("Failed to generate seed", e);
}
}
/**
* Gets the hardware serial number of this device.
*
* @return serial number or {@code null} if not available.
*/
private static String getDeviceSerialNumber() {
// We're using the Reflection API because of Build.SERIAL is only
// available since API Level 9 (Gingerbread, Android 2.3).
try {
return (String) Build.class.getField("SERIAL").get(null);
} catch (Exception ignored) {
return null;
}
}
private static byte[] getBuildFingerprintAndDeviceSerial() {
StringBuilder result = new StringBuilder();
String fingerprint = Build.FINGERPRINT;
if (fingerprint != null) {
result.append(fingerprint);
}
String serial = getDeviceSerialNumber();
if (serial != null) {
result.append(serial);
}
try {
return result.toString().getBytes("UTF-8");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("UTF-8 encoding not supported");
}
}
}
}
关于我错了的任何主意吗？预先谢谢你
最后，我自己解决。我发布解决方案只是为了帮助将来会寻找类似情况的任何人。我错误地用encrypt方法检索了iv数组，我在生成另一个iv向量，而不是使用secretKeys中包含的向量。
private static String encrypt(InputStream inputStream, SecretKeys secretKeys, File fileToWrite)
throws GeneralSecurityException {
Cipher aesCipherForEncryption = Cipher.getInstance(CIPHER_TRANSFORMATION);
aesCipherForEncryption.init(Cipher.ENCRYPT_MODE, secretKeys.getConfidentialityKey(), new IvParameterSpec(secretKeys.getIv()));
saveFile(inputStream, aesCipherForEncryption, fileToWrite);
return secretKeys.toString();
}