241–250 of 386 posts
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It is killing me that you didn't rename Signal to Axolotl.
Why? "Axolotl" at least has seriously pronunciation issues so I am glad it is not used "user-side".
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fair enough! https://www.schneier.com/blog/archives/2016/03/possible_gove... i think this is why source is a must. if a user compiled and installed the app themselves, and hypothetically had the entire stack above it be similarly open, then it would prevent the kind of attack mentioned. do you agree? if the source is closed anywhere in the stack, or pushed out in a walled garden as it is currently, then it allows the…
I understand what you're saying. I don't think source is bad thing! Source is good. But I think you're a little confused here. The cryptographic building blocks of the new WhatsApp protocol are available in source code. You can get source for the Signal Protocol (fka Axolotl). You can get source for the Noise framework. WhatsApp borrowed these tools from a very open secure messaging project. You're unhappy that the s…
is there any way to verify that they actually use (an implementation of) this in their builds ? there's only one client, and I presume we can't make a third-party client to show it's interoperable with their implementation of the axolotl code.
Okay, first off: This is great. The most popular messaging app finally gets the security it needed. And we've just rolled out E2E to 1b 'monthly active users'. However, I have always wondered one thing about WhatsApp: How does it generate any kind of meaningful revenue? Apparently they've ditched the old $1 subscription model [0], and even that was so loosely enforced that I have never paid a single cent for WhatsApp…
Does this include file transfers, if so, how? Curious because when sending a .webm video from an Android device to a iOS device, the video file was transcoded on WhatsApp servers and then delivered to the iOS device as H264/mp4 (since iOS can not play .webm files) This should no longer be working.
What the article fails to mention: 1) I would assume Facebook still gets unencrypted access to my address book for use with their shadow profiles 2) We have zero control over what key the client encrypts the messages for. Is it only the other peer's phone? Or is it for the peer's phone plus Facebook for analysis of the messages? Especially 2) is of some concern to me (against 1 I can't protect myself anyways because…
I think this is a reasonable analysis. I would refine it this way (examples are only for illustrative purposes): Tier 1 secure messengers: all possible tradeoffs in favor of security made; use for worst-case adversaries: - Signal/TextSecure - Pond - PGP† - OTR Tier 2 secure messengers: serious secure messaging protocols that make some tradeoffs in favor of adoption and usability; use for normal messages of low sensit…
If i take a look at axolotl, in scenario Alice send message to bob when Bob is offline:
(1) , (2)
MK = HMAC-HASH(CKs, "0") // (3)
msg = Enc(HKs, Ns || PNs || DHRs) || Enc(MK, plaintext)
Ns = Ns + 1
CKs = HMAC-HASH(CKs, "1") // (4)
return msg
We can see that Alice re-use CKs to get a new symmetric key. So if an attacker get CKs(n) he could easily compute CKs(n+1) CKs is not a long term key, but we cannot honestly call this _perfect_ futur secrecy... One more thing, if I remember correctly, according of perfect forward secrecy definition, an implementation must NOT re-use previous session key to derive a new one ...
I'm wrong ?
(1) Quoted from https://github.com/trevp/axolotl/wiki
(2) see session_cipher_get_or_create_message_keys (https://github.com/WhisperSystems/libaxolotl-c/blob/0640b5ac...)
(3) i think we should read MK = HKDF(HMAC-HASH(CKs, 0x00) see ratchet_chain_key_get_message_keys (https://github.com/WhisperSystems/libaxolotl-c/blob/0640b5ac...)
(4) i think we should read MK = HMAC-HASH(CKs, 0x02) see ratchet_chain_key_create_next (https://github.com/WhisperSystems/libaxolotl-c/blob/0640b5ac...)
Does anyone know how the WhatsApp backup to Google Drive is encrypted? If so, how can it be decrypted so easily from a new phone with the same number. Clearly either WhatsApp or Google have to store a key - or am I missing something here?
Does this mean that WhatsApp can talk to Signal Private Messenger app?
No. Signal would probebly like to add Federation as a feature but they have not done so (yet?). So even if Whatsapp would be down to do it, what I don't think, then their would still be a technical issue. Actor is a messanger that seems to focus on federation and they want to use Singal Protocol as well. So maybe they will devlop software for that. However their is still the issue if Whatsapp would want to do that.
It supported federation with Signal. But they removed it as the hassle of supporting the server was hard, the code was outdated and everyone agreed if you wanted that level of security, just install Signal yourself.
Just replace cure-all-diseases secret ingredient from mysterious land with unbreakable secure algorithm that takes trillions of years to crack.
The algorithm is only secure under specific circumstances. The implementation might be not secure, the hardware it runs on can be tampered, the advertised security could only be the best case scenario but some protocols degrade encryption during handshakes... and you can start simplifying the thing by several orders of magnitude.