peergos-arch-20min-v03.pdf

Transcript

1. peergos.org ▪ Ian Preston ▪ @ianopolous Is your data secure?
2. peergos.org ▪ Ian Preston ▪ @ianopolous
3. peergos.org ▪ Ian Preston ▪ @ianopolous  I want to store my files online, but without Dropbox being able to read them.  I want to selectively share my photos, but without Facebook seeing them.  I want to store my files online, but not in a company that could go bankrupt.
4. peergos.org ▪ Ian Preston ▪ @ianopolous What do I want? Security  Safelogin  Strong crypto, ideallypost- quantum  Hide filemetadata  Free of SSLCas  Free ofDNS
5. peergos.org ▪ Ian Preston ▪ @ianopolous What do I want? Security  Safelogin  Strong crypto, ideallypost- quantum  Hide filemetadata  Free of SSLCas  Free ofDNS Control • Selfhostable • Selectively sharefiles • Hidecontacts • Pseudonymous
6. peergos.org ▪ Ian Preston ▪ @ianopolous What do I want? Security  Safelogin  Strong crypto, ideallypost- quantum  Hide filemetadata  Free of SSLCas  Free ofDNS Convenience Control • Selfhostable • Selectively sharefiles • Hidecontacts • Pseudonymous • Webinterface • Log in from anydevice • Filesyncing • Publishfiles • Resilient • As convenient as Dropbox,Facebook
7. peergos.org ▪ Ian Preston ▪ @ianopolous Control
8. peergos.org ▪ Ian Preston ▪ @ianopolous Overall architecture IPFS Hash → data IPNS Public key → Hash PKI Server PKI root hash Peergos Server Follow requests Peergos Client
9. peergos.org ▪ Ian Preston ▪ @ianopolous Basic structure • Global file system • /username/yourfiles • Tree of symmetric keys (TweetNaCl) with cryptographic links between (Cryptree) • Location + Key = cryptographic access token or capability (CAP) • Explicitly don't use convergent encryption!
10. peergos.org ▪ Ian Preston ▪ @ianopolous Base key Directory File Metadata key Parent key Metadata key Sub-directory Parent key Metadata key work File contents Parent key Base key Data key Cryptree ianopolous thesis.tex 72 KiB Modified: 15:23 14/3/2016 text/plain
11. peergos.org ▪ Ian Preston ▪ @ianopolous Chunk raw file Raw file 5 MiB 5 MiB 5 MiB
12. peergos.org ▪ Ian Preston ▪ @ianopolous Chunk raw file Encrypt chunk Raw file 5 MiB 5 MiB 5 MiB 5 MiB
13. peergos.org ▪ Ian Preston ▪ @ianopolous Chunk raw file Encrypt chunk Split Raw file 5 MiB 5 MiB 5 MiB 5 MiB 40 * 128 KiB
14. peergos.org ▪ Ian Preston ▪ @ianopolous Chunk raw file Encrypt chunk Split Upload Raw file 5 MiB 5 MiB 5 MiB 5 MiB 40 * 128 KiB IPFS Encrypted metadata + fragment hashes
15. peergos.org ▪ Ian Preston ▪ @ianopolous File system CHAMP Cryptree node File fragment CHAMP node File fragment File fragment CHAMP node CHAMP node
16. peergos.org ▪ Ian Preston ▪ @ianopolous How does sharing work? • Users have a public boxing key • To send a follow request: create a directory /myname/sharing/friendname • Send a read CAP to this directory encrypted to friend's public key • Shared files are currently vulnerable to a quantum computer • Will move to post-quantum sharing as soon as a clear candidate arrives
17. peergos.org ▪ Ian Preston ▪ @ianopolous Convenience
18. peergos.org ▪ Ian Preston ▪ @ianopolous Decentralized login? Scrypt hash Password Username Signing keypair ~1 second Only ever stored in RAM, never written to disk or transmitted Root key Boxing keypair
19. peergos.org ▪ Ian Preston ▪ @ianopolous Public links? Read (or write) CAP encoded in a URL: demo.peergos.net/#Public_writing_Key/Subspace_label/Decryption_Key Material after # is not sent to the server → file still isn't exposed to the network Can share an individual file or a folder.
20. peergos.org ▪ Ian Preston ▪ @ianopolous Security
21. peergos.org ▪ Ian Preston ▪ @ianopolous Can a login be cracked? • Brute force is practically impossible with a good password • Random 14 character alpha-numeric password has ~ 2^84 ~ 10^25 possibilities • A GPU can calculate ~ 1M scrypt hashes/s (measured by litecoin users) • One GPU cracking a single user’s login would take 10^19 seconds or ~ 300 billion years • 300 million GPUs would take 1000 years • GPU purchase cost = 300 billion USD
22. peergos.org ▪ Ian Preston ▪ @ianopolous What about quantum computer based attacks?
23. peergos.org ▪ Ian Preston ▪ @ianopolous  All encryption is symmetric encryption using TweetNaCl, or hashing through scrypt  Both have no known quantum attacks
24. peergos.org ▪ Ian Preston ▪ @ianopolous “But Javascript crypto is insecure!”
25. peergos.org ▪ Ian Preston ▪ @ianopolous Threat model A (casual user): • Trusts our public server • Trust the SSL certificate hierarchy Depends on your threat model...
26. peergos.org ▪ Ian Preston ▪ @ianopolous Threat model B (paranoid user): • Doesn't trust our public server • Doesn't trust the SSL chain Run Peergos on own machine AIR GAP Faraday Cage Binary, compiled with 3 different compilers, from signed source
27. peergos.org ▪ Ian Preston ▪ @ianopolous Build security • Reproducible builds, both server and front end • Do not use npm! Only 8 JS dependencies, all vendored • Have our own deterministic replacement for webpack, and minifiers • Self host all assets • Most of the client code is written in a type-safe language (Java) and cross-compiled to JS
28. peergos.org ▪ Ian Preston ▪ @ianopolous Demo
29. peergos.org ▪ Ian Preston ▪ @ianopolous Current status: Pre alpha • Web-interface – done • Use actual IPNS – to do • Tor integration – to do • Fuse client – done • Security audit – to do • Granting write access – not in UI yet • Private keystore of friends (TOFU) – done
30. peergos.org ▪ Ian Preston ▪ @ianopolous Join community! • Sign up to hear when our alpha is ready (soon): https://peergos.org • Read our book: https://peergos.github.io/book • Try our demo at https://demo.peergos.net • Contribute https://github.com/peergos/peergos • Currently we are a team of 4 contributors
31. peergos.org ▪ Ian Preston ▪ @ianopolous Questions?