aboutsummaryrefslogtreecommitdiff
path: root/src/server.rs
diff options
context:
space:
mode:
Diffstat (limited to 'src/server.rs')
-rw-r--r--src/server.rs136
1 files changed, 0 insertions, 136 deletions
diff --git a/src/server.rs b/src/server.rs
deleted file mode 100644
index 137d6b3..0000000
--- a/src/server.rs
+++ /dev/null
@@ -1,136 +0,0 @@
-//! SRP server implementation
-//!
-//! # Usage
-//! First receive user's username and public value `a_pub`, retrieve from a
-//! database `UserRecord` for a given username, generate `b` (e.g. 512 bits
-//! long) and initialize SRP server instance:
-//!
-//! ```ignore
-//! use srp::groups::G_2048;
-//!
-//! let (username, a_pub) = conn.receive_handshake();
-//! let user = db.retrieve_user_record(username);
-//! let b = rng.gen_iter::<u8>().take(64).collect::<Vec<u8>>();
-//! let server = SrpServer::<Sha256>::new(&user, &a_pub, &b, &G_2048)?;
-//! ```
-//!
-//! Next send to user `b_pub` and `salt` from user record:
-//!
-//! ```ignore
-//! let b_pub = server.get_b_pub();
-//! conn.reply_to_handshake(&user.salt, b_pub);
-//! ```
-//!
-//! And finally recieve user proof, verify it and send server proof in the
-//! reply:
-//!
-//! ```ignore
-//! let user_proof = conn.receive_proof();
-//! let server_proof = server.verify(user_proof)?;
-//! conn.send_proof(server_proof);
-//! ```
-//!
-//! To get the shared secret use `get_key` method. As alternative to using
-//! `verify` method it's also possible to use this key for authentificated
-//! encryption.
-use std::marker::PhantomData;
-
-use num::{BigUint, Zero};
-use digest::Digest;
-use generic_array::GenericArray;
-
-use tools::powm;
-use types::{SrpAuthError, SrpGroup};
-
-/// Data provided by users upon registration, usually stored in the database.
-pub struct UserRecord<'a> {
- pub username: &'a [u8],
- pub salt: &'a [u8],
- /// Password verifier
- pub verifier: &'a [u8],
-}
-
-/// SRP server state
-pub struct SrpServer<D: Digest> {
- b: BigUint,
- a_pub: BigUint,
- b_pub: BigUint,
-
- key: GenericArray<u8, D::OutputSize>,
-
- d: PhantomData<D>
-}
-
-impl< D: Digest> SrpServer< D> {
- /// Create new server state.
- pub fn new(user: &UserRecord, a_pub: &[u8], b: &[u8], params: &SrpGroup)
- -> Result<Self, SrpAuthError>
- {
- let a_pub = BigUint::from_bytes_be(a_pub);
- // Safeguard against malicious A
- if &a_pub % &params.n == BigUint::zero() {
- return Err(SrpAuthError { description: "Malicious a_pub value" })
- }
- let v = BigUint::from_bytes_be(user.verifier);
- let b = BigUint::from_bytes_be(b) % &params.n;
- let k = params.compute_k::<D>();
- // kv + g^b
- let interm = (k * &v) % &params.n;
- let b_pub = (interm + &params.powm(&b)) % &params.n;
- // H(A || B)
- let u = {
- let mut d = D::new();
- d.input(&a_pub.to_bytes_be());
- d.input(&b_pub.to_bytes_be());
- d.result()
- };
- let d = Default::default();
- //(Av^u) ^ b
- let key = {
- let u = BigUint::from_bytes_be(&u);
- let t = (&a_pub * powm(&v, &u, &params.n)) % &params.n;
- let s = powm(&t, &b, &params.n);
- D::digest(&s.to_bytes_be())
- };
- Ok(Self { b, a_pub, b_pub, key, d})
- }
-
- /// Get private `b` value. (see `new_with_b` documentation)
- pub fn get_b(&self) -> Vec<u8> {
- self.b.to_bytes_be()
- }
-
- /// Get public `b_pub` value for sending to the user.
- pub fn get_b_pub(&self) -> Vec<u8> {
- self.b_pub.to_bytes_be()
- }
-
- /// Get shared secret between user and the server. (do not forget to verify
- /// that keys are the same!)
- pub fn get_key(&self) -> GenericArray<u8, D::OutputSize> {
- self.key.clone()
- }
-
- /// Process user proof of having the same shared secret and compute
- /// server proof for sending to the user.
- pub fn verify(&self, user_proof: &[u8])
- -> Result<GenericArray<u8, D::OutputSize>, SrpAuthError>
- {
- // M = H(A, B, K)
- let mut d = D::new();
- d.input(&self.a_pub.to_bytes_be());
- d.input(&self.b_pub.to_bytes_be());
- d.input(&self.key);
-
- if user_proof == d.result().as_slice() {
- // H(A, M, K)
- let mut d = D::new();
- d.input(&self.a_pub.to_bytes_be());
- d.input(user_proof);
- d.input(&self.key);
- Ok(d.result())
- } else {
- Err(SrpAuthError { description: "Incorrect user proof" })
- }
- }
-}