diff options
author | Артём Павлов [Artyom Pavlov] <newpavlov@gmail.com> | 2017-08-14 07:37:17 +0300 |
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committer | Артём Павлов [Artyom Pavlov] <newpavlov@gmail.com> | 2017-08-14 07:37:17 +0300 |
commit | 331727194c231a10dc2e296922e09aa0e888f4bd (patch) | |
tree | 46e2a32679f399a7584b3b33d3986611195a395c /srp/src | |
parent | defd41c0ee00cf06930b733e9ab06163bc6ad1cf (diff) | |
download | PAKEs-331727194c231a10dc2e296922e09aa0e888f4bd.tar.xz |
PAKE repository reorganization
Diffstat (limited to 'srp/src')
-rw-r--r-- | srp/src/client.rs | 212 | ||||
-rw-r--r-- | srp/src/groups.rs | 56 | ||||
-rw-r--r-- | srp/src/groups/1024.bin | 3 | ||||
-rw-r--r-- | srp/src/groups/1536.bin | 1 | ||||
-rw-r--r-- | srp/src/groups/2048.bin | 2 | ||||
-rw-r--r-- | srp/src/groups/3072.bin | bin | 0 -> 384 bytes | |||
-rw-r--r-- | srp/src/groups/4096.bin | bin | 0 -> 512 bytes | |||
-rw-r--r-- | srp/src/groups/6144.bin | bin | 0 -> 768 bytes | |||
-rw-r--r-- | srp/src/groups/8192.bin | bin | 0 -> 1024 bytes | |||
-rw-r--r-- | srp/src/k_sha1_1024.bin | 1 | ||||
-rw-r--r-- | srp/src/lib.rs | 79 | ||||
-rw-r--r-- | srp/src/prime.bin | 1 | ||||
-rw-r--r-- | srp/src/server.rs | 136 | ||||
-rw-r--r-- | srp/src/tools.rs | 19 | ||||
-rw-r--r-- | srp/src/types.rs | 64 |
15 files changed, 574 insertions, 0 deletions
diff --git a/srp/src/client.rs b/srp/src/client.rs new file mode 100644 index 0000000..4348f4f --- /dev/null +++ b/srp/src/client.rs @@ -0,0 +1,212 @@ +//! SRP client implementation. +//! +//! # Usage +//! First create SRP client struct by passing to it SRP parameters (shared +//! between client and server) and randomly generated `a`: +//! +//! ```ignore +//! use srp::groups::G_2048; +//! use sha2::Sha256; +//! +//! let a = rng.gen_iter::<u8>().take(64).collect::<Vec<u8>>(); +//! let client = SrpClient::<Sha256>::new(&a, &G_2048); +//! ``` +//! +//! Next send handshake data (username and `a_pub`) to the server and receive +//! `salt` and `b_pub`: +//! +//! ```ignore +//! let a_pub = client.get_a_pub(); +//! let (salt, b_pub) = conn.send_handshake(username, a_pub); +//! ``` +//! +//! Compute private key using `salt` with any password hashing function. +//! You can use method from SRP-6a, but it's recommended to use specialized +//! password hashing algorithm instead (e.g. PBKDF2, argon2 or scrypt). +//! Next create verifier instance, note that `get_verifier` consumes client and +//! can return error in case of malicious `b_pub`. +//! +//! ```ignore +//! let private_key = srp_private_key::<Sha256>(username, password, salt); +//! let verifier = client.get_verifier(&private_key, &b_pub)?; +//! ``` +//! +//! Finally verify the server: first generate user proof, +//! send it to the server and verify server proof in the reply. Note that +//! `verify_server` method will return error in case of incorrect server reply. +//! +//! ```ignore +//! let user_proof = verifier.get_proof(); +//! let server_proof = conn.send_proof(user_proof); +//! let key = verifier.verify_server(server_proof)?; +//! ``` +//! +//! `key` contains shared secret key between user and the server. Alternatively +//! you can directly extract shared secret key using `get_key()` method and +//! handle authentification through different (secure!) means (e.g. by using +//! authentificated cipher mode). +//! +//! For user registration on the server first generate salt (e.g. 32 bytes long) +//! and get password verifier which depends on private key. Send useranme, salt +//! and password verifier over protected channel to protect against MitM for +//! registration. +//! +//! ```ignore +//! let pwd_verifier = client.get_password_verifier(&private_key); +//! conn.send_registration_data(username, salt, pwd_verifier); +//! ``` + +//let buf = rng.gen_iter::<u8>().take(l).collect::<Vec<u8>>(); +use std::marker::PhantomData; + +use num::{BigUint, Zero}; +use digest::Digest; +use generic_array::GenericArray; + +use tools::powm; +use types::{SrpAuthError, SrpGroup}; + +/// SRP client state before handshake with the server. +pub struct SrpClient<'a, D: Digest> { + params: &'a SrpGroup, + + a: BigUint, + a_pub: BigUint, + + d: PhantomData<D> +} + +/// SRP client state after handshake with the server. +pub struct SrpClientVerifier<D: Digest> { + proof: GenericArray<u8, D::OutputSize>, + server_proof: GenericArray<u8, D::OutputSize>, + key: GenericArray<u8, D::OutputSize>, +} + +/// Compute user private key as described in the RFC 5054. Consider using proper +/// password hashing algorithm instead. +pub fn srp_private_key<D: Digest>(username: &[u8], password: &[u8], salt: &[u8]) + -> GenericArray<u8, D::OutputSize> +{ + let p = { + let mut d = D::new(); + d.input(username); + d.input(b":"); + d.input(password); + d.result() + }; + let mut d = D::new(); + d.input(salt); + d.input(&p); + d.result() +} + +impl<'a, D: Digest> SrpClient<'a, D> { + /// Create new SRP client instance. + pub fn new(a: &[u8], params: &'a SrpGroup) -> Self { + let a = BigUint::from_bytes_be(a); + let a_pub = params.powm(&a); + + Self { params, a, a_pub, d: Default::default() } + } + + /// Get password verfier for user registration on the server + pub fn get_password_verifier(&self, private_key: &[u8]) -> Vec<u8> { + let x = BigUint::from_bytes_be(&private_key); + let v = self.params.powm(&x); + v.to_bytes_be() + } + + fn calc_key(&self, b_pub: &BigUint, x: &BigUint, u: &BigUint) + -> GenericArray<u8, D::OutputSize> + { + let n = &self.params.n; + let k = self.params.compute_k::<D>(); + let interm = (k * self.params.powm(x)) % n; + // Because we do operation in modulo N we can get: (kv + g^b) < kv + let v = if b_pub > &interm { + (b_pub - &interm) % n + } else { + (n + b_pub - &interm) % n + }; + // S = |B - kg^x| ^ (a + ux) + let s = powm(&v, &(&self.a + (u*x) % n ), n); + D::digest(&s.to_bytes_be()) + } + + /// Process server reply to the handshake. + pub fn process_reply(self, private_key: &[u8], b_pub: &[u8]) + -> Result<SrpClientVerifier<D>, SrpAuthError> + { + let u = { + let mut d = D::new(); + d.input(&self.a_pub.to_bytes_be()); + d.input(b_pub); + BigUint::from_bytes_be(&d.result()) + }; + + let b_pub = BigUint::from_bytes_be(b_pub); + + // Safeguard against malicious B + if &b_pub % &self.params.n == BigUint::zero() { + return Err(SrpAuthError{ description: "Malicious b_pub value" }) + } + + let x = BigUint::from_bytes_be(&private_key); + let key = self.calc_key(&b_pub, &x, &u); + // M1 = H(A, B, K) + let proof = { + let mut d = D::new(); + d.input(&self.a_pub.to_bytes_be()); + d.input(&b_pub.to_bytes_be()); + d.input(&key); + d.result() + }; + + // M2 = H(A, M1, K) + let server_proof = { + let mut d = D::new(); + d.input(&self.a_pub.to_bytes_be()); + d.input(&proof); + d.input(&key); + d.result() + }; + + Ok(SrpClientVerifier { + proof: proof, + server_proof: server_proof, + key: key, + }) + } + + /// Get public ephemeral value for handshaking with the server. + pub fn get_a_pub(&self) -> Vec<u8> { + self.a_pub.to_bytes_be() + } +} + +impl<D: Digest> SrpClientVerifier<D> { + /// Get shared secret key without authenticating server, e.g. for using with + /// authenticated encryption modes. DO NOT USE this method without + /// some kind of secure authentification. + pub fn get_key(self) -> GenericArray<u8, D::OutputSize> { + self.key + } + + /// Verification data for sending to the server. + pub fn get_proof(&self) -> GenericArray<u8, D::OutputSize> { + self.proof.clone() + } + + /// Verify server reply to verification data. It will return shared secret + /// key in case of success. + pub fn verify_server(self, reply: &[u8]) + -> Result<GenericArray<u8, D::OutputSize>, SrpAuthError> + { + if self.server_proof.as_slice() != reply { + Err(SrpAuthError{ description: "Incorrect server proof" }) + } else { + Ok(self.key) + } + } +} diff --git a/srp/src/groups.rs b/srp/src/groups.rs new file mode 100644 index 0000000..246134e --- /dev/null +++ b/srp/src/groups.rs @@ -0,0 +1,56 @@ +//! Groups from [RFC 5054](https://tools.ietf.org/html/rfc5054) +//! +//! It is strongly recommended to use them instead of custom generated +//! groups. Additionally it is not recommended to use `G_1024` and `G_1536`, +//! they are provided only for compatability with the legacy software. +use types::SrpGroup; +use num::BigUint; + +lazy_static! { + pub static ref G_1024: SrpGroup = SrpGroup { + n: BigUint::from_bytes_be(include_bytes!("groups/1024.bin")), + g: BigUint::from_bytes_be(&[2]), + }; +} + +lazy_static! { + pub static ref G_1536: SrpGroup = SrpGroup { + n: BigUint::from_bytes_be(include_bytes!("groups/1536.bin")), + g: BigUint::from_bytes_be(&[2]), + }; +} + +lazy_static! { + pub static ref G_2048: SrpGroup = SrpGroup { + n: BigUint::from_bytes_be(include_bytes!("groups/2048.bin")), + g: BigUint::from_bytes_be(&[2]), + }; +} + +lazy_static! { + pub static ref G_3072: SrpGroup = SrpGroup { + n: BigUint::from_bytes_be(include_bytes!("groups/3072.bin")), + g: BigUint::from_bytes_be(&[5]), + }; +} + +lazy_static! { + pub static ref G_4096: SrpGroup = SrpGroup { + n: BigUint::from_bytes_be(include_bytes!("groups/4096.bin")), + g: BigUint::from_bytes_be(&[5]), + }; +} + +lazy_static! { + pub static ref G_6144: SrpGroup = SrpGroup { + n: BigUint::from_bytes_be(include_bytes!("groups/6144.bin")), + g: BigUint::from_bytes_be(&[5]), + }; +} + +lazy_static! { + pub static ref G_8192: SrpGroup = SrpGroup { + n: BigUint::from_bytes_be(include_bytes!("groups/8192.bin")), + g: BigUint::from_bytes_be(&[19]), + }; +} diff --git a/srp/src/groups/1024.bin b/srp/src/groups/1024.bin new file mode 100644 index 0000000..7ce0aa3 --- /dev/null +++ b/srp/src/groups/1024.bin @@ -0,0 +1,3 @@ + +֜3 +`rau<1L%evtt8;H֒PI\`]״aTֶΎi]IU){)ffWh<rl/nQ8vC[/
\ No newline at end of file diff --git a/srp/src/groups/1536.bin b/srp/src/groups/1536.bin new file mode 100644 index 0000000..c3a5972 --- /dev/null +++ b/srp/src/groups/1536.bin @@ -0,0 +1 @@ +<9'z*{ۥLaKM_O_Un'QƩK`z)X;CU"|gЁ4ȹy`㺶=GTűvN?KSݝ>+n94'/=$Ćew.C}lBsJ̷|&J㩾/鸵).Z^G碌$BI#Mv5
\ No newline at end of file diff --git a/srp/src/groups/2048.bin b/srp/src/groups/2048.bin new file mode 100644 index 0000000..23207c6 --- /dev/null +++ b/srp/src/groups/2048.bin @@ -0,0 +1,2 @@ +kA2Jf^X/re1=`Ps)˴큓uwg=#K1
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\ No newline at end of file diff --git a/srp/src/groups/3072.bin b/srp/src/groups/3072.bin Binary files differnew file mode 100644 index 0000000..7e1a84d --- /dev/null +++ b/srp/src/groups/3072.bin diff --git a/srp/src/groups/4096.bin b/srp/src/groups/4096.bin Binary files differnew file mode 100644 index 0000000..82463c0 --- /dev/null +++ b/srp/src/groups/4096.bin diff --git a/srp/src/groups/6144.bin b/srp/src/groups/6144.bin Binary files differnew file mode 100644 index 0000000..83a559a --- /dev/null +++ b/srp/src/groups/6144.bin diff --git a/srp/src/groups/8192.bin b/srp/src/groups/8192.bin Binary files differnew file mode 100644 index 0000000..b1f32ac --- /dev/null +++ b/srp/src/groups/8192.bin diff --git a/srp/src/k_sha1_1024.bin b/srp/src/k_sha1_1024.bin new file mode 100644 index 0000000..4408438 --- /dev/null +++ b/srp/src/k_sha1_1024.bin @@ -0,0 +1 @@ +uVZ,f\>o
\ No newline at end of file diff --git a/srp/src/lib.rs b/srp/src/lib.rs new file mode 100644 index 0000000..df11ae9 --- /dev/null +++ b/srp/src/lib.rs @@ -0,0 +1,79 @@ +//! [Secure Remote Password][1] (SRP) protocol implementation. +//! +//! This implementation is generic over hash functions using +//! [`Digest`](https://docs.rs/digest) trait, so you will need to choose a hash +//! function, e.g. `Sha256` from [`sha2`](https://crates.io/crates/sha2) crate. +//! Additionally this crate allows to use a specialized password hashing +//! algorithm for private key computation instead of method described in the +//! SRP literature. +//! +//! Compatability with over implementations was not yet tested. +//! +//! # Usage +//! Add `srp` dependecy to your `Cargo.toml`: +//! +//! ```toml +//! [dependencies] +//! rand = "0.3" +//! ``` +//! +//! and this to your crate root: +//! +//! ```rust +//! extern crate srp; +//! ``` +//! +//! Next read documentation for [`client`](client/index.html) and +//! [`server`](server/index.html) modules. +//! +//! # Algorithm description +//! Here we briefly describe implemented algroithm. For additionall information +//! refer to SRP literature. All arithmetic is done modulo `N`, where `N` is a +//! large safe prime (`N = 2q+1`, where `q` is prime). Additionally `g` MUST be +//! a generator modulo `N`. It's STRONGLY recommended to use SRP parameters +//! provided by this crate in the [`groups`](groups/index.html) module. +//! +//! Client | | Server +//! ------------------------|---------------|------------------------ +//! | — `I` —> | (lookup `s`, `v`) +//! `x = PH(P, s)` | <— `s`, `v` — | +//! `a_pub = g^a` | — `a_pub` —> | `b_pub = k*v + g^b` +//! `u = H(a_pub || b_pub)` | <— `b_pub` — | `u = H(a_pub || b_pub)` +//! `s = (b_pub - k*g^x)^(a+u*x)` | | `S = (b_pub - k*g^x)^(a+u*x)` +//! `K = H(s)` | | `K = H(s)` +//! `M1 = H(A || B || K)` | — `M1` —> | (verify `M1`) +//! (verify `M2`) | <— `M2` — | `M2 = H(A || M1 || K)` +//! +//! `||` denotes concatenation, variables and notations have the following +//! meaning: +//! +//! - `I` — user identity (username) +//! - `P` — user password +//! - `H` — one-way hash function +//! - `PH` — password hashing algroithm, in the RFC 5054 described as +//! `H(s || H(I || ":" || P))` +//! - `^` — (modular) exponentiation +//! - `x` — user private key +//! - `s` — salt generated by user and stored on the server +//! - `v` — password verifier equal to `g^x` and stored on the server +//! - `a`, `b` — secret ephemeral values (at least 256 bits in length) +//! - `A`, `B` — Public ephemeral values +//! - `u` — scrambling parameter +//! - `k` — multiplier parameter (`k = H(N || g)` in SRP-6a) +//! +//! [1]: https://en.wikipedia.org/wiki/Secure_Remote_Password_protocol +//! [2]: https://tools.ietf.org/html/rfc5054 +extern crate num; +extern crate digest; +extern crate generic_array; +#[macro_use] +extern crate lazy_static; + +#[cfg(test)] +extern crate sha_1; + +mod tools; +pub mod client; +pub mod server; +pub mod types; +pub mod groups; diff --git a/srp/src/prime.bin b/srp/src/prime.bin new file mode 100644 index 0000000..d2109b7 --- /dev/null +++ b/srp/src/prime.bin @@ -0,0 +1 @@ +_P<=èyCp^ >Hhw
Bb{+2,ZuHEXrӋto 'Tw;䪗Dl'$2/A-tcK2-懘2u7
\ No newline at end of file diff --git a/srp/src/server.rs b/srp/src/server.rs new file mode 100644 index 0000000..137d6b3 --- /dev/null +++ b/srp/src/server.rs @@ -0,0 +1,136 @@ +//! 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 % ¶ms.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) % ¶ms.n; + let k = params.compute_k::<D>(); + // kv + g^b + let interm = (k * &v) % ¶ms.n; + let b_pub = (interm + ¶ms.powm(&b)) % ¶ms.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, ¶ms.n)) % ¶ms.n; + let s = powm(&t, &b, ¶ms.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" }) + } + } +} diff --git a/srp/src/tools.rs b/srp/src/tools.rs new file mode 100644 index 0000000..8cb6910 --- /dev/null +++ b/srp/src/tools.rs @@ -0,0 +1,19 @@ +use num::BigUint; + +pub fn powm(base: &BigUint, exp: &BigUint, modulus: &BigUint) -> BigUint { + let zero = BigUint::new(vec![0]); + let one = BigUint::new(vec![1]); + let two = BigUint::new(vec![2]); + let mut exp = exp.clone(); + let mut result = one.clone(); + let mut base = base % modulus; + + while exp > zero { + if &exp % &two == one { + result = (result * &base) % modulus; + } + exp = exp >> 1; + base = (&base * &base) % modulus; + } + result +} diff --git a/srp/src/types.rs b/srp/src/types.rs new file mode 100644 index 0000000..810132c --- /dev/null +++ b/srp/src/types.rs @@ -0,0 +1,64 @@ +//! Additional SRP types. +use std::{fmt, error}; +use num::BigUint; +use tools::powm; +use digest::Digest; + +/// SRP authentification error. +#[derive(Debug, Copy, Clone, Eq, PartialEq)] +pub struct SrpAuthError { + pub(crate) description: &'static str +} + +impl fmt::Display for SrpAuthError { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + write!(f, "SRP authentification error") + } +} + +impl error::Error for SrpAuthError { + fn description(&self) -> &str { + self.description + } +} + +/// Group used for SRP computations +#[derive(Debug, Clone, Eq, PartialEq)] +pub struct SrpGroup { + /// A large safe prime (N = 2q+1, where q is prime) + pub n: BigUint, + /// A generator modulo N + pub g: BigUint, +} + +impl SrpGroup { + pub(crate) fn powm(&self, v: &BigUint) -> BigUint { + powm(&self.g, v, &self.n) + } + + /// Compute `k` with given hash function and return SRP parameters + pub(crate) fn compute_k<D: Digest>(&self) -> BigUint { + let n = self.n.to_bytes_be(); + let g_bytes = self.g.to_bytes_be(); + let mut buf = vec![0u8; n.len()]; + let l = n.len() - g_bytes.len(); + buf[l..].copy_from_slice(&g_bytes); + + let mut d = D::new(); + d.input(&n); + d.input(&buf); + BigUint::from_bytes_be(&d.result()) + } +} + +#[cfg(test)] +mod tests { + use ::groups::G_1024; + use sha_1::Sha1; + + #[test] + fn test_k_1024_sha1() { + let k = G_1024.compute_k::<Sha1>().to_bytes_be(); + assert_eq!(&k, include_bytes!("k_sha1_1024.bin")); + } +} |