Cryptographic security rules ?

[prodnet]

Hello,

Your Shamir secret sharing code around meet the cryptographic security rules ?
Some details like : integrity checks and side-channel resistance

Recommandations :

*Be side channel resistant (timing, branch, cache)
*Secure the shared secret with a MAC
*Use the platform (OS) randomness source

**These slip-ups can often fully compromise the security of the scheme.

[prodnet]

Please let me know !
Thanks.

[iancoleman]

This tool uses the library https://github.com/amper5and/secrets.js

That library has been improved by https://github.com/grempe/secrets.js so I will look into upgrading it here.

• side channels - no explicit work done on this, any suggestions?
• no MAC but it can be done as a second step using another tool
• uses secure randomness and alerts the user if not available (see secrets.js:L103)

[prodnet]

Thank you for you reply.

Why this secure shared secret with a MAC, could not be implement directly in this source code?

It would be great if you could inspire you and implement in javascript, other sharing schemes as in this project:

https://github.com/Qbicz/multi-secret-sharing
Implemented and ready-to-use multi secrets sharing schemes are:

Roy-Adhikari
Lin-Yeh
Herranz-Ruiz-Saez.

[prodnet]

And this :
https://github.com/brndnmtthws/seed-otp

[prodnet]

This is Trezor Implementation:
https://github.com/trezor/python-shamir-mnemonic/

[iancoleman]

Feel free to use those tools instead. I wrote this one as a way to use https://github.com/amper5and/secrets.js since there was no demo app for it. I think you're looking for something different to this tool. If you have specific suggestions or pull requests that'd be great.

I like SLIP-0039 and have recommended it as the preferred alternative to my other secret sharing project for mnemonics called shamir39.

[prodnet]

Where can I find an implementation of "SLIP-0039" without dependencies (python), as a simple "standalone.html" file, like yours?
If it does not exist, can you do this conversion?
Thanks.

[iancoleman]

I don't know of any web-based implementations of slip-0039. Would be a good project.