The Tor Browser / file comparison
comparison: mobile/android/base/sync/crypto/KeyBundle.java
mobile/android/base/sync/crypto/KeyBundle.java
- branch
- TOR_BUG_3246
- changeset 4
- fc2d59ddac77
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| -1:000000000000 | 0:ad4c0ffc5328 |
|---|---|
| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 package org.mozilla.gecko.sync.crypto; | |
| 6 | |
| 7 import java.io.UnsupportedEncodingException; | |
| 8 import java.security.InvalidKeyException; | |
| 9 import java.security.NoSuchAlgorithmException; | |
| 10 import java.util.Arrays; | |
| 11 | |
| 12 import javax.crypto.KeyGenerator; | |
| 13 import javax.crypto.Mac; | |
| 14 | |
| 15 import org.mozilla.apache.commons.codec.binary.Base64; | |
| 16 import org.mozilla.gecko.sync.Utils; | |
| 17 | |
| 18 public class KeyBundle { | |
| 19 private static final String KEY_ALGORITHM_SPEC = "AES"; | |
| 20 private static final int KEY_SIZE = 256; | |
| 21 | |
| 22 private byte[] encryptionKey; | |
| 23 private byte[] hmacKey; | |
| 24 | |
| 25 // These are the same for every sync key bundle. | |
| 26 private static final byte[] EMPTY_BYTES = {}; | |
| 27 private static final byte[] ENCR_INPUT_BYTES = {1}; | |
| 28 private static final byte[] HMAC_INPUT_BYTES = {2}; | |
| 29 | |
| 30 /* | |
| 31 * Mozilla's use of HKDF for getting keys from the Sync Key string. | |
| 32 * | |
| 33 * We do exactly 2 HKDF iterations and make the first iteration the | |
| 34 * encryption key and the second iteration the HMAC key. | |
| 35 * | |
| 36 */ | |
| 37 public KeyBundle(String username, String base32SyncKey) throws CryptoException { | |
| 38 if (base32SyncKey == null) { | |
| 39 throw new IllegalArgumentException("No sync key provided."); | |
| 40 } | |
| 41 if (username == null || username.equals("")) { | |
| 42 throw new IllegalArgumentException("No username provided."); | |
| 43 } | |
| 44 // Hash appropriately. | |
| 45 try { | |
| 46 username = Utils.usernameFromAccount(username); | |
| 47 } catch (NoSuchAlgorithmException e) { | |
| 48 throw new IllegalArgumentException("Invalid username."); | |
| 49 } catch (UnsupportedEncodingException e) { | |
| 50 throw new IllegalArgumentException("Invalid username."); | |
| 51 } | |
| 52 | |
| 53 byte[] syncKey = Utils.decodeFriendlyBase32(base32SyncKey); | |
| 54 byte[] user = username.getBytes(); | |
| 55 | |
| 56 Mac hmacHasher; | |
| 57 try { | |
| 58 hmacHasher = HKDF.makeHMACHasher(syncKey); | |
| 59 } catch (NoSuchAlgorithmException e) { | |
| 60 throw new CryptoException(e); | |
| 61 } catch (InvalidKeyException e) { | |
| 62 throw new CryptoException(e); | |
| 63 } | |
| 64 assert(hmacHasher != null); // If makeHMACHasher doesn't throw, then hmacHasher is non-null. | |
| 65 | |
| 66 byte[] encrBytes = Utils.concatAll(EMPTY_BYTES, HKDF.HMAC_INPUT, user, ENCR_INPUT_BYTES); | |
| 67 byte[] encrKey = HKDF.digestBytes(encrBytes, hmacHasher); | |
| 68 byte[] hmacBytes = Utils.concatAll(encrKey, HKDF.HMAC_INPUT, user, HMAC_INPUT_BYTES); | |
| 69 | |
| 70 this.hmacKey = HKDF.digestBytes(hmacBytes, hmacHasher); | |
| 71 this.encryptionKey = encrKey; | |
| 72 } | |
| 73 | |
| 74 public KeyBundle(byte[] encryptionKey, byte[] hmacKey) { | |
| 75 this.setEncryptionKey(encryptionKey); | |
| 76 this.setHMACKey(hmacKey); | |
| 77 } | |
| 78 | |
| 79 /** | |
| 80 * Make a KeyBundle with the specified base64-encoded keys. | |
| 81 * | |
| 82 * @return A KeyBundle with the specified keys. | |
| 83 */ | |
| 84 public static KeyBundle fromBase64EncodedKeys(String base64EncryptionKey, String base64HmacKey) throws UnsupportedEncodingException { | |
| 85 return new KeyBundle(Base64.decodeBase64(base64EncryptionKey.getBytes("UTF-8")), | |
| 86 Base64.decodeBase64(base64HmacKey.getBytes("UTF-8"))); | |
| 87 } | |
| 88 | |
| 89 /** | |
| 90 * Make a KeyBundle with two random 256 bit keys (encryption and HMAC). | |
| 91 * | |
| 92 * @return A KeyBundle with random keys. | |
| 93 */ | |
| 94 public static KeyBundle withRandomKeys() throws CryptoException { | |
| 95 KeyGenerator keygen; | |
| 96 try { | |
| 97 keygen = KeyGenerator.getInstance(KEY_ALGORITHM_SPEC); | |
| 98 } catch (NoSuchAlgorithmException e) { | |
| 99 throw new CryptoException(e); | |
| 100 } | |
| 101 | |
| 102 keygen.init(KEY_SIZE); | |
| 103 byte[] encryptionKey = keygen.generateKey().getEncoded(); | |
| 104 byte[] hmacKey = keygen.generateKey().getEncoded(); | |
| 105 | |
| 106 return new KeyBundle(encryptionKey, hmacKey); | |
| 107 } | |
| 108 | |
| 109 public byte[] getEncryptionKey() { | |
| 110 return encryptionKey; | |
| 111 } | |
| 112 | |
| 113 public void setEncryptionKey(byte[] encryptionKey) { | |
| 114 this.encryptionKey = encryptionKey; | |
| 115 } | |
| 116 | |
| 117 public byte[] getHMACKey() { | |
| 118 return hmacKey; | |
| 119 } | |
| 120 | |
| 121 public void setHMACKey(byte[] hmacKey) { | |
| 122 this.hmacKey = hmacKey; | |
| 123 } | |
| 124 | |
| 125 @Override | |
| 126 public boolean equals(Object o) { | |
| 127 if (!(o instanceof KeyBundle)) { | |
| 128 return false; | |
| 129 } | |
| 130 KeyBundle other = (KeyBundle) o; | |
| 131 return Arrays.equals(other.encryptionKey, this.encryptionKey) && | |
| 132 Arrays.equals(other.hmacKey, this.hmacKey); | |
| 133 } | |
| 134 | |
| 135 @Override | |
| 136 public int hashCode() { | |
| 137 throw new UnsupportedOperationException("No hashCode for KeyBundle."); | |
| 138 } | |
| 139 } |
