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Cryptpad: Zero Knowledge, Collaborative Real Time Editing

beta.cryptpad.fr

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Re: Cryptpad: Zero Knowledge, Collaborative Real Time Editing

#21

Post by schoen »

Ar-Curunir wrote: post #17

Why do people insist on using the term zero knowledge for simple semantically secure encryption? Zero knowledge has a very specific meaning inside cryptography. Encrypting something does not make it "zero knowledge".

I think this is a terminological suggestion from SpiderOak

https://spideroak.com/features/zero-knowledge

It's true that it doesn't match the technical meaning of zero knowledge from cryptography (although maybe arguably the meaning of the technical term could be extended to this situation in a trivial way: rather than a proof or protocol involving Bob from which Bob doesn't learn certain information, this is a protocol not involving Bob from which Bob also doesn't learn certain information).

Re: Cryptpad: Zero Knowledge, Collaborative Real Time Editing

#22

Post by CiPHPerCoder »

schoen wrote: post #21
Ar-Curunir wrote: post #17

Why do people insist on using the term zero knowledge for simple semantically secure encryption? Zero knowledge has a very specific meaning inside cryptography. Encrypting something does not make it "zero knowledge".

I think this is a terminological suggestion from SpiderOak https://spideroak.com/features/zero-knowledge It's true that it doesn't match the technical meaning of zero knowledge from cryptography (although maybe arguably the meaning of the technical term could be extended to this situation in a trivial way: rather than a proof or protocol involving Bob from which Bob doesn't learn certain information, this is a protoc…

Counter argument: https://paragonie.com/blog/2016/08/crypto-misnomers-zero-kno...

Summary: zero-knowledge applies to authentication protocols, not encryption protocols.

Re: Cryptpad: Zero Knowledge, Collaborative Real Time Editing

#23

Post by no_protocol »

Ar-Curunir wrote: post #17

Why do people insist on using the term zero knowledge for simple semantically secure encryption? Zero knowledge has a very specific meaning inside cryptography. Encrypting something does not make it "zero knowledge".

I had the same feeling when reading the copy on the site. I looked for an explanation of what they mean by the statement, but couldn't find one. Google led me to a Spider Oak page that seems to use the terminology in a similar manner [1].

I have a hard time even accepting this definition of "zero knowledge' on its own, separate from the existing cryptographic one. Wouldn't the host at least know things like the size of the encrypted data? Time it was sent? Etc.

[1] https://spideroak.com/features/zero-knowledge

Re: Cryptpad: Zero Knowledge, Collaborative Real Time Editing

#24

Post by schoen »

CiPHPerCoder wrote: post #22
schoen wrote: post #21

Earlier quoted context omitted.

I think this is a terminological suggestion from SpiderOak https://spideroak.com/features/zero-knowledge It's true that it doesn't match the technical meaning of zero knowledge from cryptography (although maybe arguably the meaning of the technical term could be extended to this situation in a trivial way: rather than a proof or protocol involving Bob from which Bob doesn't learn certain information, this is a protoc…

Counter argument: https://paragonie.com/blog/2016/08/crypto-misnomers-zero-kno... Summary: zero-knowledge applies to authentication protocols, not encryption protocols.

I think I'm inclined to agree with that interpretation. I wish we had a clearer term for systems where you don't trust an intermediary with some kind of access. (We often say "end-to-end encrypted", but that's kind of weird for file storage or other data-at-rest situations.)

Re: Cryptpad: Zero Knowledge, Collaborative Real Time Editing

#25

Post by no_protocol »

the_duke wrote: post #9
no_protocol wrote: post #7

Earlier quoted context omitted.

From a glance at the GitHub page, it looks like you can self-host the project. Is "bower install" a possible attack vector as well? I'm unfamiliar with it.

Bower is a package manager for Javascript libraries. So the only attack vector would be a MIT attack, intercepting the requests to the Bower registry.

Or a hijacked GitHub repository/maintainer?

Re: Cryptpad: Zero Knowledge, Collaborative Real Time Editing

#26

Post by CiPHPerCoder »

schoen wrote: post #24
CiPHPerCoder wrote: post #22

Earlier quoted context omitted.

Counter argument: https://paragonie.com/blog/2016/08/crypto-misnomers-zero-kno... Summary: zero-knowledge applies to authentication protocols, not encryption protocols.

I think I'm inclined to agree with that interpretation. I wish we had a clearer term for systems where you don't trust an intermediary with some kind of access. (We often say "end-to-end encrypted", but that's kind of weird for file storage or other data-at-rest situations.)

> I wish we had a clearer term for systems where you don't trust an intermediary with some kind of access.

We already have one or more of:

  - Confidential
  - End-to-end encrypted (contrasted with, but often in addition to,
    transport-layer encryption)
  - Privacy-preserving
  - Least authority (with respect to the service operator)
  - Peer-to-peer privacy
I'm one degree of separation from several SpiderOak engineers and think highly of them overall. However, this choice of marketing copy is one point we vehemently disagree on.

Re: Cryptpad: Zero Knowledge, Collaborative Real Time Editing

#28

Post by anarcat »

no_protocol wrote: post #5

I have often seen claims that doing any kind of crypto in (browser) javascript is dangerous. Does this fall into that trap? How can I safely share the URL to someone without already using an established encrypted communication method? Is the encryption key stored in my browser history?

yes.

you can't.

and yes.

Re: Cryptpad: Zero Knowledge, Collaborative Real Time Editing

#29

Post by infodroid »

Ar-Curunir wrote: post #17

Why do people insist on using the term zero knowledge for simple semantically secure encryption? Zero knowledge has a very specific meaning inside cryptography. Encrypting something does not make it "zero knowledge".

> Why do people insist on using the term zero knowledge for simple semantically secure encryption?

Note that in the domain of privacy-enhancing technologies the term "zero-knowledge" does not refer to "semantically secure encryption". Instead it is used to mean that a service provider does not have access to user data, and that this claim can be proven cryptographically. The use of the term zero-knowledge to promote privacy-respecting services dates back to at least 1997 with the founding of the Canadian company Zero-Knowledge Systems [1], which provided anonymous communication services [2].

[1] https://en.wikipedia.org/wiki/Zero_Knowledge_Systems [2] http://edition.cnn.com/TECH/computing/9902/11/browsanon.idg/

Re: Cryptpad: Zero Knowledge, Collaborative Real Time Editing

#30

Post by habitue »

no_protocol wrote: post #5

I have often seen claims that doing any kind of crypto in (browser) javascript is dangerous. Does this fall into that trap? How can I safely share the URL to someone without already using an established encrypted communication method? Is the encryption key stored in my browser history?

The reason crypto in the browser is dangerous is because the crypto algorithms come from the server (they aren't built into the browser) so you have to verify them every time you go to the site to know they're doing everything properly. They could easily change them to no ops for you at the request of the NSA or whatever and you wouldn't know. So on the basis of that, I don't think this project avoids that problem
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