Honeywords
Here is a simple but clever idea. Seed password files with dummy entries that will trigger an alarm when used. That way a site can know when a hacker is trying to decrypt the password file.
Entries Tagged "encryption"
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Another WWII Message Decoded
It’s a really interesting code and story. (The first link has the most detailed information about the code and the cryptanalysis.)
Apple's iMessage Encryption Seems to Be Pretty Good
The U.S. Drug Enforcement Agency has complained (in a classified report, not publicly) that Apple’s iMessage end-to-end encryption scheme can’t be broken. On the one hand, I’m not surprised; end-to-end encryption of a messaging system is a fairly easy cryptographic problem, and it should be unbreakable. On the other hand, it’s nice to have some confirmation that Apple is looking out for the users’ best interests and not the governments’.
Still, it’s impossible for us to know if iMessage encryption is actually secure. It’s certainly possible that Apple messed up somewhere, and since we have no idea how their encryption actually works, we can’t verify its functionality. It would be really nice if Apple would release the specifications of iMessage security.
EDITED TO ADD (4/8): There’s more to this story:
The DEA memo simply observes that, because iMessages are encrypted and sent via the Internet through Apple’s servers, a conventional wiretap installed at the cellular carrier’s facility isn’t going to catch those iMessages along with conventional text messages. Which shouldn’t exactly be surprising: A search of your postal mail isn’t going to capture your phone calls either; they’re just different communications channels. But the CNET article strongly implies that this means encrypted iMessages cannot be accessed by law enforcement at all. That is almost certainly false.
The question is whether iMessage uses true end-to-end encryption, or whether Apple has copies of the keys.
Another article.
New RC4 Attack
This is a really clever attack on the RC4 encryption algorithm as used in TLS.
We have found a new attack against TLS that allows an attacker to recover a limited amount of plaintext from a TLS connection when RC4 encryption is used. The attacks arise from statistical flaws in the keystream generated by the RC4 algorithm which become apparent in TLS ciphertexts when the same plaintext is repeatedly encrypted at a fixed location across many TLS sessions.
The attack is very specialized:
The attack is a multi-session attack, which means that we require a target plaintext to be repeatedly sent in the same position in the plaintext stream in multiple TLS sessions. The attack currently only targets the first 256 bytes of the plaintext stream in sessions. Since the first 36 bytes of plaintext are formed from an unpredictable Finished message when SHA-1 is the selected hashing algorithm in the TLS Record Protocol, these first 36 bytes cannot be recovered. This means that the attack can recover 220 bytes of TLS-encrypted plaintext.
The number of sessions needed to reliably recover these plaintext bytes is around 230, but already with only 224 sessions, certain bytes can be recovered reliably.
Is this a big deal? Yes and no. The attack requires the identical plaintext to be repeatedly encrypted. Normally, this would make for an impractical attack in the real world, but http messages often have stylized headers that are identical across a conversation—for example, cookies. On the other hand, those are the only bits that can be decrypted. Currently, this attack is pretty raw and unoptimized—so it’s likely to become faster and better.
There’s no reason to panic here. But let’s start to move away from RC4 to something like AES.
New al Qaeda Encryption Tool
There’s not a lot of information—and quite a lot of hyperbole—in this article:
With the release of the Asrar Al Dardashah plugin, GIMF promised “secure correspondence” based on the Pidgin chat client, which supports multiple chat platforms, including Yahoo Messenger, Windows Live Messenger, AOL Instant Messenger, Google Talk and Jabber/XMPP.
“The Asrar Al Dardashah plugin supports most of the languages in the world through the use of Unicode encoding, including Arabic, English, Urdu, Pashto, Bengali and Indonesian,” stated the announcement, which was posted on several top online Jihadist forums and GIMF’s official website.
“The plugin is easy and quick to use, and, like its counterpart, the Asrar Al Mujahideen program, it uses the technical algorithm RSA for asymmetric encryption, which is based [on] a pair of interrelated keys: a public key allocated for encrypting and a private key used for decrypting,” GIMF’s statement said. “To use the plugin, both of the communicating parties should install and activate the plugin and produce and import the Asrar Al Mujahideen private key into the Asrar Al Dardashah plugin, which automatically produces the corresponding public key of 2048-bit-length for use. It offers a level of encryption which has not been cracked or broken and can be relied upon entirely to protect the confidentiality of sensitive communication[s].”
The Security of the Mega File-Sharing Service
Ever since the launch of Kim Dotcom’s file-sharing service, I have been asked about the unorthodox encryption and security system.
I have not reviewed it, and don’t have an opinion. All I know is what I read: this, this, this, this, and this.
Please add other links in the comments.
EDITED TO ADD (1/24): Also this.
Breaking Hard-Disk Encryption
The newly announced ElcomSoft Forensic Disk Decryptor can decrypt BitLocker, PGP, and TrueCrypt. And it’s only $300. How does it work?
Elcomsoft Forensic Disk Decryptor acquires the necessary decryption keys by analyzing memory dumps and/or hibernation files obtained from the target PC. You’ll thus need to get a memory dump from a running PC (locked or unlocked) with encrypted volumes mounted, via a standard forensic product or via a FireWire attack. Alternatively, decryption keys can also be derived from hibernation files if a target PC is turned off.
This isn’t new. I wrote about AccessData doing the same thing in 2007:
Even so, none of this might actually matter. AccessData sells another program, Forensic Toolkit, that, among other things, scans a hard drive for every printable character string. It looks in documents, in the Registry, in e-mail, in swap files, in deleted space on the hard drive … everywhere. And it creates a dictionary from that, and feeds it into PRTK.
And PRTK breaks more than 50 percent of passwords from this dictionary alone.
It’s getting harder and harder to maintain good file security.
China Now Blocking Encryption
The “Great Firewall of China” is now able to detect and block encryption:
A number of companies providing “virtual private network” (VPN) services to users in China say the new system is able to “learn, discover and block” the encrypted communications methods used by a number of different VPN systems.
China Unicom, one of the biggest telecoms providers in the country, is now killing connections where a VPN is detected, according to one company with a number of users in China.
EDITED TO ADD (1/14): Some interesting blog comments from an American living and working in China.
Possible Decryption of World War II Pigeon Message
A Canadian claims that the message is based on a WWII codebook. A spokesman from GCHQ remains dubious, but says they’ll be happy to look at the proposed solution.
EDITED TO ADD (1/14): The backstory. Skepticism about the alleged deciphering.
Sidebar photo of Bruce Schneier by Joe MacInnis.