Introduce Ed25519 verify as an external.

substrate/native-runtime/support/src/lib.rs

@@ -3,6 +3,9 @@ extern crate environmental;
 extern crate polkadot_state_machine;
 extern crate tiny_keccak;
 
+use std::fmt;
+use primitives::ed25519;
+
 pub use std::vec::Vec;
 pub use std::rc::Rc;
 pub use std::cell::RefCell;
@@ -11,7 +14,6 @@ pub use std::slice;
 pub use std::mem::{size_of, transmute, swap, uninitialized};
 
 pub use polkadot_state_machine::Externalities;
-use std::fmt;
 
 // TODO: use the real error, not NoError.
 
@@ -63,9 +65,9 @@ pub fn storage_into<T: Sized>(_key: &[u8]) -> Option<T> {
 	}).unwrap_or(None)
 }
 
-pub fn set_storage(_key: &[u8], _value: &[u8]) {
+pub fn set_storage(key: &[u8], value: &[u8]) {
 	ext::with(|holder|
-		holder.ext.set_storage(_key.to_vec(), _value.to_vec())
+		holder.ext.set_storage(key.to_vec(), value.to_vec())
 	);
 }
 
@@ -79,6 +81,11 @@ pub fn chain_id() -> u64 {
 /// Conduct a Keccak-256 hash of the given data.
 pub use tiny_keccak::keccak256;
 
+/// Verify a ed25519 signature.
+pub fn ed25519_verify(sig: &[u8; 64], msg: &[u8], pubkey: &[u8; 32]) -> bool {
+	ed25519::verify(&sig[..], msg, &pubkey[..])
+}
+
 /// Execute the given closure with global function available whose functionality routes into the
 /// externalities `ext`. Forwards the value that the closure returns.
 pub fn with_externalities<R, F: FnOnce() -> R>(ext: &mut Externalities<Error=NoError>, f: F) -> R {