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Hello
* Rasmus Dahlberg (rgdd)
* Affiliations
* Karlstad University (PhD student)
* Mullvad VPN (software engineer)
Purpose of this mini talk - make people aware of sigsum logging
* Work-in-progress, still early days
* Plenty of opportunity to:
* get involved
* design
* code
* apply pattern of transparent logging (pick a use-case)
* operate experimental logs and/or witnesses
* etc.
* shape the project as we move forward
* aim: free and open source
The basics
* Sigsum, short for "signed checksum"
* Sigsum logging is about adding signed checksums into a transparent log
* Think of this as Certificate Transparency, but:
* s/Certificate/checksum
* checksum is the output of a cryptographic hash function
Backdrop and motivation
* You can already achieve transparency for cryptographic checksums by piggy-backing on Certificate Transparency
* Encode hash into a certificate
* Mozilla proposed a form of Binary Transparency this way a while back
* https://wiki.mozilla.org/Security/Binary_Transparency
* But could really be <anything> transparency because <anything> is hashed
* With sigsum logging you can do this without the runaround of:
* first encoding that hash with ASN.1 (as a certificate)
* then doing a ping-poing with a certificate authority
* and learning about ecosystem specific constructs like
* promises of public logging, "SCTs"
* eventually you will realize that you are kind of on your own in terms of gossip-audit models
* so what you are left with is a weirdly encoded hash and a log that you trust blindly
* We try to bring transparency to signed checksums in a more sensible way
It is fair to say that we place a large emphasis on minimalism
* Keep it simple
But at the same time, important features shouldn't be left out
* E.g., we want features that make log operations less costly and less scary
* anti-spam
* anti-poison
* sharding (helps with log life cycles)
* We also want features - or maybe I should say considerations - that facilitate adoption of transparent logging patterns
* if your users already download data from a repository or a website, and you want to bring transparency to that data
* great, that is the only communication pattern we assume for end-users
* "preserved data flows"
* few and simple (de)serialization parsers
* no cryptographic agility (simplifies protocol, tooling, etc.)
* built-in mechanism to ensure a globally consistent log
* simpified version of witness cosigning
* log is not a party that you trust blindly
Current status
* We have a proof of concept up and running (log + witness)
* Tooling is basically non-existing
* format data with printf, pipe into curl :)
* If you have a use-case for transparent logging, or if you want to learn more, or if this sounds like fun and you would like to get involved:
* irc: #sigsum @ oftc (the conversation happens here)
* talk to me here on gather
* our repos are currently on github, contains code and some documentation
* github.com/sigsum
* www.sigsum.org
(I will also post link to a non-persistent pad with this mini-talk in the chat.)
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