2021 edition bump + doc improvements; MSRV 1.56 (#80)

- Bumps both `spake2` and `srp` to Rust 2021 edition
- Uses the new `doc = include_str!(...)` attribute to include README.md
  files in the rustdoc
- Improves the README.md files, adding an initial one for `srp`
- clippy fixes for Rust 1.56

1 files changed, 62 insertions, 0 deletions

diff --git a/srp/tests/srp.rs b/srp/tests/srp.rs
new file mode 100644
index 0000000..bf6c30f
--- /dev/null
+++ b/srp/tests/srp.rs
@@ -0,0 +1,62 @@
+use rand::RngCore;
+use sha2::Sha256;
+
+use srp::client::{srp_private_key, SrpClient};
+use srp::groups::G_2048;
+use srp::server::{SrpServer, UserRecord};
+
+fn auth_test(reg_pwd: &[u8], auth_pwd: &[u8]) {
+    let mut rng = rand::rngs::OsRng::new().unwrap();
+    let username = b"alice";
+
+    // Client instance creation
+    let mut a = [0u8; 64];
+    rng.fill_bytes(&mut a);
+    let client = SrpClient::<Sha256>::new(&a, &G_2048);
+
+    // Registration
+    let mut salt = [0u8; 16];
+    rng.fill_bytes(&mut salt);
+    let reg_priv_key = srp_private_key::<Sha256>(username, reg_pwd, &salt);
+    let verif = client.get_password_verifier(&reg_priv_key);
+
+    // User sends handshake
+    let a_pub = client.get_a_pub();
+
+    // Server retrieve user record from db and processes handshake
+    let user = UserRecord {
+        username,
+        salt: &salt,
+        verifier: &verif,
+    };
+    let mut b = [0u8; 64];
+    rng.fill_bytes(&mut b);
+    let server = SrpServer::<Sha256>::new(&user, &a_pub, &b, &G_2048).unwrap();
+    let (salt, b_pub) = (&user.salt, server.get_b_pub());
+
+    // Client processes handshake reply
+    let auth_priv_key = srp_private_key::<Sha256>(username, auth_pwd, salt);
+    let client2 = client.process_reply(&auth_priv_key, &b_pub).unwrap();
+    let proof = client2.get_proof();
+
+    // Server processes verification data
+    println!("Client verification");
+    let proof2 = server.verify(&proof).unwrap();
+    let server_key = server.get_key();
+
+    // Client verifies server
+    println!("Server verification");
+    let user_key = client2.verify_server(&proof2).unwrap();
+    assert_eq!(server_key, user_key, "server and client keys are not equal");
+}
+
+#[test]
+fn good_password() {
+    auth_test(b"password", b"password");
+}
+
+#[test]
+#[should_panic]
+fn bad_password() {
+    auth_test(b"password", b"paSsword");
+}