Consolidate crypto functionality in ethcore-crypto. (#8432)

* Consolidate crypto functionality in `ethcore-crypto`.

- Move `ecdh`/`ecies` modules to `ethkey`.
- Refactor `ethcore-crypto` to use file per module.
- Replace `subtle` with `ethcore_crypto::is_equal`.
- Add `aes_gcm` module to `ethcore-crypto`.

* Rename `aes::{encrypt,decrypt,decrypt_cbc}` ...

... to `aes::{encrypt_128_ctr,decrypt_128_ctr,decrypt_128_cbc}`.

util/network-devp2p/src/connection.rs

@@ -34,7 +34,7 @@ use rcrypto::symmetriccipher::*;
 use rcrypto::buffer::*;
 use tiny_keccak::Keccak;
 use bytes::{Buf, BufMut};
-use crypto;
+use ethkey::crypto;
 use network::{Error, ErrorKind};
 
 const ENCRYPTED_HEADER_LEN: usize = 32;

util/network-devp2p/src/handshake.rs

@@ -25,7 +25,7 @@ use connection::{Connection};
 use node_table::NodeId;
 use io::{IoContext, StreamToken};
 use ethkey::{KeyPair, Public, Secret, recover, sign, Generator, Random};
-use crypto::{ecdh, ecies};
+use ethkey::crypto::{ecdh, ecies};
 use network::{Error, ErrorKind, HostInfo};
 
 #[derive(PartialEq, Eq, Debug)]