wallet-core

Couldn't they have used CryptMT [0] instead of MT19937 (or whatever mersenne twister implementation they had)? Saying mersenne twister should not be used is a bit misleading as it all depends on the specific implementations and needs of the application. Anyhow, they could still have used webcrypto through WASM or even through JavaScript (as they can send the data back). This is really not a problem with WASM but moreso with the stupid implementation of this wallet. edit: According to this PR they were indeed using std::mt19937 [1]. In fact I would go further ahead and say this is a general issue of C++ itself which just does not provide good PRNGs in the stdlib at all, with multiple ways of achieving different (but similarly broken) PRNG results. [0]: https://en.m.wikipedia.org/wiki/CryptMT [1]: https://github.com/trustwallet/wallet-core/

WASM is a "pure" VM/execution environment without any standard system calls or library functions. Given that, you'll need to provide your own seed and your own cryptographically-secure PRNG implementation. Trust Wallet seems to have botched the latter [1] (in fact, it looks to me like they aren't even understanding the implications of that decision based on the PR description [2]). How is that WASMs fault? [1] https://github.com/trustwallet/wallet-core/pull/2240 [2] They say that their choice of using the Mersenne Twister is "inspired by emscripten", which does no such thing.

The flaw was not in a dependency but Trust Wallet's first party code [1]. They decided that Mersenne Twister would be sufficient for generating cryptographically random data and specifically called it "secure" [2]. Very unfortunate. [1] https://github.com/trustwallet/wallet-core/blob/3.1.0/wasm/s... [2] https://github.com/trustwallet/wallet-core/pull/2240

I am a bit perplexed about Binance recommending self-custodial wallets, heavily promoting its own Trust Wallet[0]. They are even offering zero withdrawal fee for transfers from Binance to Trust. Given that only the core of Trust is open-source [1], is it possible that the closed-source parts contain some backdoor? [0] - https://trustwallet.com/ [1] - https://github.com/trustwallet/wallet-core