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updated key generation

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This commit is contained in:
Sebastian Stenzel
2016-06-10 14:04:55 +02:00
parent e2b94ff6ef
commit 414bbef1a7
2 changed files with 23 additions and 19 deletions
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28
main/filesystem-crypto/src/main/java/org/cryptomator/crypto/engine/impl/CryptorImpl.java
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@@ -18,6 +18,7 @@ import java.security.SecureRandom;
import java.util.Arrays;
import java.util.concurrent.atomic.AtomicReference;
import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
@@ -81,14 +82,15 @@ class CryptorImpl implements Cryptor {
@Override
public void randomizeMasterkey() {
final byte[] randomBytes = new byte[KEYLENGTH_IN_BYTES];
try {
randomSource.nextBytes(randomBytes);
encryptionKey = new SecretKeySpec(randomBytes, ENCRYPTION_ALG);
randomSource.nextBytes(randomBytes);
macKey = new SecretKeySpec(randomBytes, MAC_ALG);
} finally {
Arrays.fill(randomBytes, (byte) 0x00);
KeyGenerator encKeyGen = KeyGenerator.getInstance(ENCRYPTION_ALG);
encKeyGen.init(KEYLENGTH_IN_BYTES * Byte.SIZE, randomSource);
encryptionKey = encKeyGen.generateKey();
KeyGenerator macKeyGen = KeyGenerator.getInstance(MAC_ALG);
macKeyGen.init(KEYLENGTH_IN_BYTES * Byte.SIZE, randomSource);
macKey = macKeyGen.generateKey();
} catch (NoSuchAlgorithmException e) {
throw new IllegalStateException("Hard-coded algorithm doesn't exist.", e);
}
}
@@ -116,12 +118,12 @@ class CryptorImpl implements Cryptor {
final SecretKey kek = new SecretKeySpec(kekBytes, ENCRYPTION_ALG);
this.macKey = AesKeyWrap.unwrap(kek, keyFile.getMacMasterKey(), MAC_ALG);
// future use (as soon as we need to prevent downgrade attacks):
// final Mac mac = new ThreadLocalMac(macKey, MAC_ALG).get();
// final byte[] versionMac = mac.doFinal(ByteBuffer.allocate(Integer.BYTES).putInt(CURRENT_VAULT_VERSION).array());
// if (!MessageDigest.isEqual(versionMac, keyFile.getVersionMac())) {
// destroyQuietly(macKey);
// throw new UnsupportedVaultFormatException(Integer.MAX_VALUE, CURRENT_VAULT_VERSION);
// }
// final Mac mac = new ThreadLocalMac(macKey, MAC_ALG).get();
// final byte[] versionMac = mac.doFinal(ByteBuffer.allocate(Integer.BYTES).putInt(CURRENT_VAULT_VERSION).array());
// if (!MessageDigest.isEqual(versionMac, keyFile.getVersionMac())) {
// destroyQuietly(macKey);
// throw new UnsupportedVaultFormatException(Integer.MAX_VALUE, CURRENT_VAULT_VERSION);
// }
this.encryptionKey = AesKeyWrap.unwrap(kek, keyFile.getEncryptionMasterKey(), ENCRYPTION_ALG);
} catch (InvalidKeyException e) {
throw new InvalidPassphraseException();

14
main/filesystem-crypto/src/main/java/org/cryptomator/crypto/engine/impl/FileHeaderPayload.java
View File

@@ -11,12 +11,14 @@ package org.cryptomator.crypto.engine.impl;
import java.nio.ByteBuffer;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Arrays;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.ShortBufferException;
import javax.crypto.spec.IvParameterSpec;
@@ -36,13 +38,13 @@ class FileHeaderPayload implements Destroyable {
private final SecretKey contentKey;
public FileHeaderPayload(SecureRandom randomSource) {
filesize = 0;
final byte[] contentKey = new byte[CONTENT_KEY_LEN];
this.filesize = 0;
try {
randomSource.nextBytes(contentKey);
this.contentKey = new SecretKeySpec(contentKey, AES);
} finally {
Arrays.fill(contentKey, (byte) 0x00);
KeyGenerator keyGen = KeyGenerator.getInstance(AES);
keyGen.init(CONTENT_KEY_LEN * Byte.SIZE, randomSource);
this.contentKey = keyGen.generateKey();
} catch (NoSuchAlgorithmException e) {
throw new IllegalStateException("Hard-coded algorithm doesn't exist.", e);
}
}