how to verify a signature message on a solana contract

Question

Are there any examples available? I would like to verify the signature on a contract. I hope to achieve something similar to the following:

fn verify(message: &[u8; 32], sig_bytes: &[u8; 64], signer: &Pubkey) -> bool {
    let signature = Signature::new(sig_bytes);
    let keypair = Signer::new(signer.to_bytes());
    let result = keypair.verify(message, &signature);
    result.is_ok()
}

Answer 1

While you can't perform all cryptographic operations on-chain, the runtime provides the Ed25519 program to verify signatures. Here's an example of how to use it, copied from the tests at https://github.com/solana-labs/solana/blob/166be2995ee76e51a343f04e41d348cfeb1cc8d9/sdk/src/ed25519_instruction.rs#L347:

        let privkey = ed25519_dalek::Keypair::generate(&mut thread_rng());
        let message_arr = b"hello";
        let mut instruction = new_ed25519_instruction(&privkey, message_arr);
        let mint_keypair = Keypair::new();
        let feature_set = FeatureSet::all_enabled();

        let tx = Transaction::new_signed_with_payer(
            &[instruction.clone()],
            Some(&mint_keypair.pubkey()),
            &[&mint_keypair],
            Hash::default(),
        );

        assert!(tx.verify_precompiles(&feature_set).is_ok());

You can read more at https://docs.solana.com/developing/runtime-facilities/programs#ed25519-program