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"It is simply impossible to create such a backdoor for one purpose and not expect others to try and open it." While I don't like or use Facebook. I can't agree

by zadkey 7y ago

"It is simply impossible to create such a backdoor for one purpose and not expect others to try and open it." While I don't like or use Facebook. I can't agree more with this sentiment.

elicash 7y ago
I do too. However, one thing I'd be curious to learn more about from this community... Facebook Messenger isn't encrypted now. What are the biggest examples where that has hurt users. I'm sure it happens, maybe frequently, but one thing that's impossible to get a sense of is the SIZE of the tradeoffs here. What's the biggest thing that's happened that we know about? Listening to the tech lawyers today at the Senate hearing, the pro-privacy side hasn't made a clear argument about just how bad it is now in FB's case, and just how bad it was before several years ago in Apple's case. (For FB you can understand why they wouldn't want to say their current system is a nightmare for users. Also, I understand a backdoor is different from the status quo or previous setups... not asking about a backdoor here.)
- bagacrap 7y ago
  Messenger is encrypted, just not by default. You have to choose "private conversation" to encrypt. This is probably the right choice for most users since they'd rather have access to their messages across devices than e2e encryption.
  - elicash 7y ago
    Since I'd imagine, then, that 99% or more aren't encrypted, what has been the biggest issue that has resulted from this? We could then judge that against the negative outcomes of law enforcement not having access to, say, WhatsApp messages.
aftbit 7y ago
While I support strong E2E encryption, I am not sure I buy this argument. Why couldn't they use an escrow key secured in the same ways as update signing keys? Or why couldn't they be compelled to silently push a special update that exfiltrates all of my messages in plaintext?
- mrguyorama 7y ago
  Virtual fort knox would be impossible to secure. In the modern age, whether through stupidity or malice, those keys WOULD be stolen, leaked, breached, what have you. Hell, the first time the US government tried this situation, the clipper chip, it was trivially bypassed and shown to be utterly broken by researchers
  - aftbit 7y ago
    Sure, Clipper was a disaster, but we've learned a lot about encryption since 1998. I still think key escrow and gov't backdoors are probably a bad idea, especially when you look at the US's privileged position in the internet, which should really be a global or jurisdiction-free space. However, I don't understand why it would be so much harder to protect these keys than the update signing keys that Apple, Google, Microsoft, etc (not to mention every app author including Facebook) already have to protect in order to prevent malicious actors (including nation states) from trivially bypassing all security protections by pushing a signed update to the end-user device. Honestly if your security model involves hiding from the FBI/NSA, you should not be using a cell phone to do your encryption/decryption. That device runs closed-source blobs and can be remotely configured, accessed, and updated by (at least) your carrier and the device manufacturer.
  - sjy 7y ago
    Don’t Apple, Google and Microsoft already have keys that can be used to automatically update and backdoor any of the billions of devices running their OSes?
  - tzs 7y ago
    Make it distributed. Have each phone generate a public/private key pair, and upload the public key to an anonymous repository. To escrow a key the client app uses a secret sharing system to generate 10000 key shares, with any 500 key shares being sufficient to reconstruct the escrow key. It encrypts each share with a randomly chosen public key from the anonymous repository. It sends these encrypted shares to the government. If the government wants to recover the escrow key, it has to make a public request for help in which it publishes the 10000 encrypted key shares. Have an app on the phone that can receive notification of such requests, and if it sees that your public key was used for one of the shares it asks you if you approve the government's request to recover the escrow key, and presents the government's argument in favor of this. If you approve, the app on your phone decrypts the share, encrypts it with a government key, and uploads it anonymously to the government. In effect, this system provides a jury of 10000 randomly chosen anonymous phone users to review the access request, and 500 of them have to approve in order for access to be granted.
noelsusman 7y ago
I hear this all the time but I don't understand why it's true. The security of your encrypted messages already relies on the security of the company providing the service. Facebook (and any other messaging app) can read all of your messages in plain text. Otherwise they wouldn't be able to display them to you. Allowing the government to get a warrant to retrieve those messages changes nothing about the overall security of the messaging platform. What am I missing?
- TheSoftwareGuy 7y ago
  >Facebook (and any other messaging app) can read all of your messages in plain text The point of end-to-end encryption is that this is not supposed to be true
  - edmundsauto 7y ago
    Since they control the plaintext -> encrypted transition, theoretically they could copy the plaintext payload in the encryption process. If this were hidden (say via steganographic means), it might not be detectable.
  - thu2111 7y ago
    But it is true because all end-to-end encrypted messaging apps today have both ends being ... an app written by the service provider, which gets the public keys from ... the service provider. Do you know WhatsApp encrypts your messages? Or do you just believe it because Facebook said so? How would you tell if the app was modified to disable it? Do you decompile and audit every binary sent to you by the Play Store? What abut the binaries your peers were sent? And what if their key directory served you a wrong key? E2E encryption isn't useless, but I see a whole lot of technical people confused about why it's useful. Namely, it's a legal/political hack. The law says the government can make you hand over data you have. It doesn't say the government can force you to make arbitrary changes to your life or business to enable them to have whatever data they want. Obviously this would be two very different laws with very different impact: specifically, it would be a law enabling law enforcement to compel arbitrary action. Such laws are extremely rare and usually tightly limited. But if such a law were to be passed, the technical infrastructure becomes useless. FB could just be forced to switch it off.

by zadkey 7y ago

"It is simply impossible to create such a backdoor for one purpose and not expect others to try and open it." While I don't like or use Facebook. I can't agree more with this sentiment.

elicash 7y ago

I do too. However, one thing I'd be curious to learn more about from this community... Facebook Messenger isn't encrypted now. What are the biggest examples where that has hurt users. I'm sure it happens, maybe frequently, but one thing that's impossible to get a sense of is the SIZE of the tradeoffs here. What's the biggest thing that's happened that we know about? Listening to the tech lawyers today at the Senate hearing, the pro-privacy side hasn't made a clear argument about just how bad it is now in FB's case, and just how bad it was before several years ago in Apple's case. (For FB you can understand why they wouldn't want to say their current system is a nightmare for users. Also, I understand a backdoor is different from the status quo or previous setups... not asking about a backdoor here.)

bagacrap 7y ago
Messenger is encrypted, just not by default. You have to choose "private conversation" to encrypt. This is probably the right choice for most users since they'd rather have access to their messages across devices than e2e encryption.
- elicash 7y ago
  Since I'd imagine, then, that 99% or more aren't encrypted, what has been the biggest issue that has resulted from this? We could then judge that against the negative outcomes of law enforcement not having access to, say, WhatsApp messages.

aftbit 7y ago

While I support strong E2E encryption, I am not sure I buy this argument. Why couldn't they use an escrow key secured in the same ways as update signing keys? Or why couldn't they be compelled to silently push a special update that exfiltrates all of my messages in plaintext?

mrguyorama 7y ago
Virtual fort knox would be impossible to secure. In the modern age, whether through stupidity or malice, those keys WOULD be stolen, leaked, breached, what have you. Hell, the first time the US government tried this situation, the clipper chip, it was trivially bypassed and shown to be utterly broken by researchers
- aftbit 7y ago
  Sure, Clipper was a disaster, but we've learned a lot about encryption since 1998. I still think key escrow and gov't backdoors are probably a bad idea, especially when you look at the US's privileged position in the internet, which should really be a global or jurisdiction-free space. However, I don't understand why it would be so much harder to protect these keys than the update signing keys that Apple, Google, Microsoft, etc (not to mention every app author including Facebook) already have to protect in order to prevent malicious actors (including nation states) from trivially bypassing all security protections by pushing a signed update to the end-user device. Honestly if your security model involves hiding from the FBI/NSA, you should not be using a cell phone to do your encryption/decryption. That device runs closed-source blobs and can be remotely configured, accessed, and updated by (at least) your carrier and the device manufacturer.
- sjy 7y ago
  Don’t Apple, Google and Microsoft already have keys that can be used to automatically update and backdoor any of the billions of devices running their OSes?
- tzs 7y ago
  Make it distributed. Have each phone generate a public/private key pair, and upload the public key to an anonymous repository. To escrow a key the client app uses a secret sharing system to generate 10000 key shares, with any 500 key shares being sufficient to reconstruct the escrow key. It encrypts each share with a randomly chosen public key from the anonymous repository. It sends these encrypted shares to the government. If the government wants to recover the escrow key, it has to make a public request for help in which it publishes the 10000 encrypted key shares. Have an app on the phone that can receive notification of such requests, and if it sees that your public key was used for one of the shares it asks you if you approve the government's request to recover the escrow key, and presents the government's argument in favor of this. If you approve, the app on your phone decrypts the share, encrypts it with a government key, and uploads it anonymously to the government. In effect, this system provides a jury of 10000 randomly chosen anonymous phone users to review the access request, and 500 of them have to approve in order for access to be granted.

noelsusman 7y ago

I hear this all the time but I don't understand why it's true. The security of your encrypted messages already relies on the security of the company providing the service. Facebook (and any other messaging app) can read all of your messages in plain text. Otherwise they wouldn't be able to display them to you. Allowing the government to get a warrant to retrieve those messages changes nothing about the overall security of the messaging platform. What am I missing?

TheSoftwareGuy 7y ago
>Facebook (and any other messaging app) can read all of your messages in plain text The point of end-to-end encryption is that this is not supposed to be true
- edmundsauto 7y ago
  Since they control the plaintext -> encrypted transition, theoretically they could copy the plaintext payload in the encryption process. If this were hidden (say via steganographic means), it might not be detectable.
- thu2111 7y ago
  But it is true because all end-to-end encrypted messaging apps today have both ends being ... an app written by the service provider, which gets the public keys from ... the service provider. Do you know WhatsApp encrypts your messages? Or do you just believe it because Facebook said so? How would you tell if the app was modified to disable it? Do you decompile and audit every binary sent to you by the Play Store? What abut the binaries your peers were sent? And what if their key directory served you a wrong key? E2E encryption isn't useless, but I see a whole lot of technical people confused about why it's useful. Namely, it's a legal/political hack. The law says the government can make you hand over data you have. It doesn't say the government can force you to make arbitrary changes to your life or business to enable them to have whatever data they want. Obviously this would be two very different laws with very different impact: specifically, it would be a law enabling law enforcement to compel arbitrary action. Such laws are extremely rare and usually tightly limited. But if such a law were to be passed, the technical infrastructure becomes useless. FB could just be forced to switch it off.