CODEWITHSUNDEEP
randomrusted25519
whomaniac
whomaniac

Reputation: 1298

The trait `rand_core::CryptoRng` is not implemented for `OsRng`

I've been trying to implement the example given in the following doc: https://docs.rs/ed25519-dalek/1.0.1/ed25519_dalek/

My code is simply:

extern crate rand;
extern crate ed25519_dalek;


use rand::rngs::OsRng;
use ed25519_dalek::Keypair;


fn main() {
    let mut csprng = OsRng{};
    let keypair: Keypair = Keypair::generate(&mut csprng);
}

But when I try to run I get an error saying that the CryptoRng trait is not implemented in OsRng

11  |     let keypair: Keypair = Keypair::generate(&mut csprng);
    |                                              ^^^^^^^^^^^ the trait `rand_core::CryptoRng` is not implemented for `OsRng`

However, CryptoRng is simply a marker trait, and I saw that it indeed has an empty impl for OsRng...

So what could be the issue here?

Upvotes: 9

Views: 3533

Answers (1)

Aplet123
Aplet123

Reputation: 35512

Usually when you get these confusing messages saying "trait bound not met" when it's clearly met, or "wrong type" when it's clearly the right type, you should always check package versions. As of right now (ed25519-dalek v1.0.1), it depends on rand 0.7.0 (you can also find this on crates.io). You're using a newer version of rand, with a "newer" version of the trait, and it's looking for the 0.7.0 trait while you supply the 0.8.0 trait.

The solution? Either downgrade rand to 0.7.0 or use dependency renaming to have 2 versions of rand, and use the old version for ec25519-dalek.

Upvotes: 17

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