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Talk:Services/Sync/SimplifiedCrypto: Difference between revisions
Talk:Services/Sync/SimplifiedCrypto (view source)
Revision as of 08:26, 4 December 2010
, 4 December 2010→Deriving encryption and HMAC keys from the Sync Key
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(A deep link to Utils.makeHMACKey() would be helpful here.) | (A deep link to Utils.makeHMACKey() would be helpful here.) | ||
== Upgrading existing Sync Keys to the new AES key == | |||
example: | |||
<pre> | |||
/** | |||
* See https://wiki.mozilla.org/Services/Sync/SimplifiedCrypto#Upgrading_existing_Sync_Keys_to_the_new_AES_key | |||
* for details on the algorithm. | |||
* @param aV3Passphrase | |||
* @return the v4 syncKey (serves the same purpose as the passphrase before) | |||
* @throws Exception see {@link #passwordToSymmetricKey(char[], byte[])} | |||
* @throws UnsupportedEncodingException should not happen (ASCII) | |||
*/ | |||
public String upgradeV3PassphraseToV4SyncKey(final String aV3Passphrase) throws UnsupportedEncodingException, Exception { | |||
String salt = mSyncID; | |||
KeySpec ks = new PBEKeySpec(aV3Passphrase.toCharArray(), salt.getBytes("ASCII"), 4096, 128); | |||
PBKDF2HmacSHA1Factory f = new PBKDF2HmacSHA1Factory(); | |||
SecretKey s = f.engineGenerateSecret(ks); | |||
String base32 = biz.wolschon.android.codec.binary.Base32.encode(s.getEncoded()).toLowerCase(); | |||
String syncKey = base32.replace('l', '8').replace('o', '9'); | |||
syncKey = syncKey.charAt(0) | |||
+ "-" + syncKey.substring(1, 6) | |||
+ "-" + syncKey.substring(6, 11) | |||
+ "-" + syncKey.substring(11, 16) | |||
+ "-" + syncKey.substring(16, 21) | |||
+ "-" + syncKey.substring(21, 26); | |||
Log.d(LOG_TAG, "upgraded passphrase to syncKey \"" + syncKey + "\""); | |||
return syncKey; | |||
} | |||
</pre> | |||