addressing comments

#364 (comment)

and specifics of the crate being used

neps/nep-0364.md

@@ -146,6 +146,15 @@ This NEP aims to introduce the following host function:
 ///
 /// `input_cost(num_bytes_signature + num_bytes_message, num_bytes_public_key) +
 ///  ed25519_verify_base + ed25519_verify_byte * (num_bytes_signature + num_bytes_message)`
+///
+/// # Errors
+///
+/// The signature size is fixed and equal to SIGNATURE_LENGTH (64 bytes). In case the length of signature input is not equal to
+/// SIGNATURE_LENGTH, then the function returns HostError::Ed25519VerifyInvalidInput with the message "invalid signature length".
+/// 
+/// A similar case occurs with the public key. Its size is known and its equal to PUBLIC_KEY_LENGTH (32 bytes). In case the
+/// input length provided for the publc key doesn't match PUBLIC_KEY_LENGTH, the function will return the following error:
+/// HostError::Ed25519VerifyInvalidInput with the message "invalid public key length".
 pub fn ed25519_verify(
     &mut self,
     sig_len: u64,
@@ -164,6 +173,8 @@ And a `rust-sdk` possible implementation could look like this:
 pub fn ed25519_verify(sig: &ed25519::Signature, msg: &[u8], pub_key: &ed25519::Public) -> bool;
 
 ```
+The current implementation is imported from the crate `ed25519-dalek`, version 1. It uses no feature flags
+except from the default one. This is the exact same setup used in the crate `near-crypto`.
 
 Once this NEP is approved and integrated, these functions will be available in the `near_sdk` crate in the
 `env` module.