Questions tagged [host-proof]

"host-proof" means that no unencrypted or insecure data is stored on the server or passed over the network.

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Proving ownership of an encryption key

In the context of a host-proof storage service, is there an encryption scheme that allows me to prove to the server that I own the secret key to decrypt the ciphertext I am currently uploading but (...
Thierry Sans's user avatar
16 votes
6 answers

Is the decompression of compressed and encrypted data without decryption also theoretically impossible?

We have two communication points in an information system, call them A(lice) and B(ackup). B has to store encrypted data received from A. The storage of B is encrypted, but not compressed1. B should ...
peterh's user avatar
  • 390
4 votes
3 answers

Encrypted messaging web app design

I’m implementing an encrypted messaging web app using JS. When composing a message, the user is provided with the public key of the recipients. A body field is also rendered for every recipient. After ...
tsuzuki's user avatar
  • 51
2 votes
1 answer

Client side encryption / hashing of "person ID's" with password?

What we're looking for A solution where data is stored and retrieved (!) from a server using a person ID that can only be known at the client (form of ...
Jochem's user avatar
  • 123
6 votes
2 answers

How should I implement a secure recovery of encryption?

I want to create a system to host as securely as possible encrypted data in a way that not even the system can know the content of the data, but that it could be recovered. I would like to know how ...
Nestor Mata Cuthbert's user avatar
6 votes
0 answers

How to make a "zero knowledge" cache/key-value store

I'd like to use a possibly insecure cache for storing expensive-to-calculate sensitive information. My requirements are: If the cache ever gets compromised it should reveal nothing about its ids or ...
Daan Bakker's user avatar
4 votes
1 answer

Repeatable crypto

Is there a safe way to do crypto that will always produce the same result for a given input? My use case is transferring deltas of huge files, to a backup server. The backup server has no knowledge ...
Ruben Vermeersch's user avatar
10 votes
1 answer

How do I store encrypted files on a web server and decrypt them locally?

I want to store files (images) on a public webserver and let users see them if they know a password. The server shouldn't have the unecrypted files and the server can only serve files, not perform ...
Eyal's user avatar
  • 405
7 votes
1 answer

Is this design of client side encryption secure?

I want to build a secure file storage web application. Users should be sure that server doesn't know how to decrypt files so encryption should take place at client side (i.e. in Javascript) and TLS ...
Andrei Botalov's user avatar
2 votes
1 answer

Tips on conceiving safe software messaging platform

I have a personal project in mind in which I plan to use cryptography in order to let the users be confident in the fact that, even if all data get's stolen, it would be virtually impossible to crack ...
Berzemus's user avatar
  • 175
6 votes
4 answers

Encryption algorithm that produces dummy output on incorrect passwords

Background: I've been thinking about using encryption in the context of backing up files to untrusted locations (to the point of making the file publicly and widely distributed for practically ...
Jack Singleton's user avatar
4 votes
1 answer

How can one share information using the 'host-proof' paradigm?

I am attempting to make a web-based secure password management and sharing utility, both as an academic exercise and to fully understand and feel safe about using it. I really like the idea of a "...
Travis's user avatar
  • 41
37 votes
4 answers

How can one securely generate an asymmetric key pair from a short passphrase?

Background info: I am planning on making a filehost with which one can encrypt and upload files. To protect the data against any form of hacking, I'd like not to know the encryption key ($K$) used for ...
Flumble's user avatar
  • 475
12 votes
2 answers

Encryption scheme for social-network-like data sharing data via untrusted server?

I am thinking quite a lot lately abut the problem of secure, privacy-preserving social networking. Distributing the network among trusted, preferably self-hosted servers (like Diaspora, GNU Social etc....
Denis Washington's user avatar