diff --git a/Cargo.lock b/Cargo.lock
index 5fd6e7a..cde7a43 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -685,6 +685,19 @@ dependencies = [
  "subtle",
 ]
 
+[[package]]
+name = "curve25519-dalek"
+version = "3.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "639891fde0dbea823fc3d798a0fdf9d2f9440a42d64a78ab3488b0ca025117b3"
+dependencies = [
+ "byteorder",
+ "digest",
+ "rand_core 0.5.1",
+ "subtle",
+ "zeroize",
+]
+
 [[package]]
 name = "derive_more"
 version = "0.99.14"
@@ -718,6 +731,17 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "212d0f5754cb6769937f4501cc0e67f4f4483c8d2c3e1e922ee9edbe4ab4c7c0"
 
+[[package]]
+name = "displaydoc"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "adc2ab4d5a16117f9029e9a6b5e4e79f4c67f6519bc134210d4d4a04ba31f41b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "dotenv"
 version = "0.15.0"
@@ -927,6 +951,15 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "generic-bytes"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6638d839bbd1cea640d8c5348dd82e0d545dbd364f3c2a251646eaf2ef0773b"
+dependencies = [
+ "generic-array",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.1.16"
@@ -945,8 +978,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7fcd999463524c52659517fe2cea98493cfe485d10565e7b0fb07dbba7ad2753"
 dependencies = [
  "cfg-if",
+ "js-sys",
  "libc",
  "wasi 0.10.2+wasi-snapshot-preview1",
+ "wasm-bindgen",
 ]
 
 [[package]]
@@ -1010,6 +1045,16 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
+[[package]]
+name = "hkdf"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51ab2f639c231793c5f6114bdb9bbe50a7dbbfcd7c7c6bd8475dec2d991e964f"
+dependencies = [
+ "digest",
+ "hmac",
+]
+
 [[package]]
 name = "hmac"
 version = "0.10.1"
@@ -1241,8 +1286,14 @@ name = "lldap_model"
 version = "0.1.0"
 dependencies = [
  "chrono",
+ "curve25519-dalek",
+ "getrandom 0.2.3",
+ "opaque-ke",
+ "rand 0.8.3",
  "serde",
+ "sha2",
  "sqlx",
+ "thiserror",
 ]
 
 [[package]]
@@ -1548,6 +1599,25 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "624a8340c38c1b80fd549087862da4ba43e08858af025b236e509b6649fc13d5"
 
+[[package]]
+name = "opaque-ke"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4c5e93081243e35cb270a2812883dcba34121c8d4054f6869149f2c3f7db10e3"
+dependencies = [
+ "curve25519-dalek",
+ "digest",
+ "displaydoc",
+ "generic-array",
+ "generic-bytes",
+ "hkdf",
+ "hmac",
+ "rand 0.8.3",
+ "subtle",
+ "thiserror",
+ "zeroize",
+]
+
 [[package]]
 name = "openssl"
 version = "0.10.34"
diff --git a/app/Cargo.lock b/app/Cargo.lock
index 2814914..97c1745 100644
--- a/app/Cargo.lock
+++ b/app/Cargo.lock
@@ -271,6 +271,19 @@ dependencies = [
  "subtle",
 ]
 
+[[package]]
+name = "curve25519-dalek"
+version = "3.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "639891fde0dbea823fc3d798a0fdf9d2f9440a42d64a78ab3488b0ca025117b3"
+dependencies = [
+ "byteorder",
+ "digest",
+ "rand_core 0.5.1",
+ "subtle",
+ "zeroize",
+]
+
 [[package]]
 name = "digest"
 version = "0.9.0"
@@ -280,6 +293,17 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "displaydoc"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "adc2ab4d5a16117f9029e9a6b5e4e79f4c67f6519bc134210d4d4a04ba31f41b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "dotenv"
 version = "0.15.0"
@@ -433,6 +457,15 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "generic-bytes"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6638d839bbd1cea640d8c5348dd82e0d545dbd364f3c2a251646eaf2ef0773b"
+dependencies = [
+ "generic-array",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.1.16"
@@ -451,8 +484,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7fcd999463524c52659517fe2cea98493cfe485d10565e7b0fb07dbba7ad2753"
 dependencies = [
  "cfg-if 1.0.0",
+ "js-sys",
  "libc",
  "wasi 0.10.2+wasi-snapshot-preview1",
+ "wasm-bindgen",
 ]
 
 [[package]]
@@ -551,6 +586,16 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
+[[package]]
+name = "hkdf"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51ab2f639c231793c5f6114bdb9bbe50a7dbbfcd7c7c6bd8475dec2d991e964f"
+dependencies = [
+ "digest",
+ "hmac",
+]
+
 [[package]]
 name = "hmac"
 version = "0.10.1"
@@ -699,8 +744,14 @@ name = "lldap_model"
 version = "0.1.0"
 dependencies = [
  "chrono",
+ "curve25519-dalek",
+ "getrandom 0.2.3",
+ "opaque-ke",
+ "rand 0.8.4",
  "serde",
+ "sha2",
  "sqlx",
+ "thiserror",
 ]
 
 [[package]]
@@ -916,6 +967,25 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "624a8340c38c1b80fd549087862da4ba43e08858af025b236e509b6649fc13d5"
 
+[[package]]
+name = "opaque-ke"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4c5e93081243e35cb270a2812883dcba34121c8d4054f6869149f2c3f7db10e3"
+dependencies = [
+ "curve25519-dalek",
+ "digest",
+ "displaydoc",
+ "generic-array",
+ "generic-bytes",
+ "hkdf",
+ "hmac",
+ "rand 0.8.4",
+ "subtle",
+ "thiserror",
+ "zeroize",
+]
+
 [[package]]
 name = "openssl"
 version = "0.10.35"
diff --git a/app/Cargo.toml b/app/Cargo.toml
index 0d7059a..b7608f2 100644
--- a/app/Cargo.toml
+++ b/app/Cargo.toml
@@ -9,7 +9,6 @@ anyhow = "1"
 chrono = "*"
 http = "0.2.4"
 jwt = "0.13"
-lldap_model = { path = "../model" }
 serde = "1"
 serde_json = "1"
 wasm-bindgen = "0.2"
@@ -25,5 +24,9 @@ features = [
   "console",
 ]
 
+[dependencies.lldap_model]
+path = "../model"
+features = [ "opaque_client" ]
+
 [lib]
 crate-type = ["cdylib"]
diff --git a/model/Cargo.lock b/model/Cargo.lock
index d267a6e..756c7a6 100644
--- a/model/Cargo.lock
+++ b/model/Cargo.lock
@@ -24,7 +24,7 @@ version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f200cbb1e856866d9eade941cf3aa0c5d7dd36f74311c4273b494f4ef036957"
 dependencies = [
- "getrandom",
+ "getrandom 0.2.2",
  "once_cell",
  "version_check",
 ]
@@ -223,6 +223,19 @@ dependencies = [
  "subtle",
 ]
 
+[[package]]
+name = "curve25519-dalek"
+version = "3.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "639891fde0dbea823fc3d798a0fdf9d2f9440a42d64a78ab3488b0ca025117b3"
+dependencies = [
+ "byteorder",
+ "digest",
+ "rand_core 0.5.1",
+ "subtle",
+ "zeroize",
+]
+
 [[package]]
 name = "digest"
 version = "0.9.0"
@@ -252,6 +265,17 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "displaydoc"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "adc2ab4d5a16117f9029e9a6b5e4e79f4c67f6519bc134210d4d4a04ba31f41b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "dotenv"
 version = "0.15.0"
@@ -399,6 +423,26 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "generic-bytes"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6638d839bbd1cea640d8c5348dd82e0d545dbd364f3c2a251646eaf2ef0773b"
+dependencies = [
+ "generic-array",
+]
+
+[[package]]
+name = "getrandom"
+version = "0.1.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8fc3cb4d91f53b50155bdcfd23f6a4c39ae1969c2ae85982b135750cccaf5fce"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi 0.9.0+wasi-snapshot-preview1",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.2.2"
@@ -406,8 +450,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c9495705279e7140bf035dde1f6e750c162df8b625267cd52cc44e0b156732c8"
 dependencies = [
  "cfg-if",
+ "js-sys",
  "libc",
- "wasi",
+ "wasi 0.10.2+wasi-snapshot-preview1",
+ "wasm-bindgen",
 ]
 
 [[package]]
@@ -452,6 +498,16 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
+[[package]]
+name = "hkdf"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51ab2f639c231793c5f6114bdb9bbe50a7dbbfcd7c7c6bd8475dec2d991e964f"
+dependencies = [
+ "digest",
+ "hmac",
+]
+
 [[package]]
 name = "hmac"
 version = "0.10.1"
@@ -547,8 +603,14 @@ name = "lldap_model"
 version = "0.1.0"
 dependencies = [
  "chrono",
+ "curve25519-dalek",
+ "getrandom 0.2.2",
+ "opaque-ke",
+ "rand",
  "serde",
+ "sha2",
  "sqlx",
+ "thiserror",
 ]
 
 [[package]]
@@ -753,6 +815,25 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "624a8340c38c1b80fd549087862da4ba43e08858af025b236e509b6649fc13d5"
 
+[[package]]
+name = "opaque-ke"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4c5e93081243e35cb270a2812883dcba34121c8d4054f6869149f2c3f7db10e3"
+dependencies = [
+ "curve25519-dalek",
+ "digest",
+ "displaydoc",
+ "generic-array",
+ "generic-bytes",
+ "hkdf",
+ "hmac",
+ "rand",
+ "subtle",
+ "thiserror",
+ "zeroize",
+]
+
 [[package]]
 name = "openssl"
 version = "0.10.34"
@@ -896,7 +977,7 @@ checksum = "0ef9e7e66b4468674bfcb0c81af8b7fa0bb154fa9f28eb840da5c447baeb8d7e"
 dependencies = [
  "libc",
  "rand_chacha",
- "rand_core",
+ "rand_core 0.6.2",
  "rand_hc",
 ]
 
@@ -907,7 +988,16 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e12735cf05c9e10bf21534da50a147b924d555dc7a547c42e6bb2d5b6017ae0d"
 dependencies = [
  "ppv-lite86",
- "rand_core",
+ "rand_core 0.6.2",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
+dependencies = [
+ "getrandom 0.1.16",
 ]
 
 [[package]]
@@ -916,7 +1006,7 @@ version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "34cf66eb183df1c5876e2dcf6b13d57340741e8dc255b48e40a26de954d06ae7"
 dependencies = [
- "getrandom",
+ "getrandom 0.2.2",
 ]
 
 [[package]]
@@ -925,7 +1015,7 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3190ef7066a446f2e7f42e239d161e905420ccab01eb967c9eb27d21b2322a73"
 dependencies = [
- "rand_core",
+ "rand_core 0.6.2",
 ]
 
 [[package]]
@@ -943,7 +1033,7 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "528532f3d801c87aec9def2add9ca802fe569e44a544afe633765267840abe64"
 dependencies = [
- "getrandom",
+ "getrandom 0.2.2",
  "redox_syscall",
 ]
 
@@ -1458,6 +1548,12 @@ version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5fecdca9a5291cc2b8dcf7dc02453fee791a280f3743cb0905f8822ae463b3fe"
 
+[[package]]
+name = "wasi"
+version = "0.9.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
+
 [[package]]
 name = "wasi"
 version = "0.10.2+wasi-snapshot-preview1"
diff --git a/model/Cargo.toml b/model/Cargo.toml
index e172cc3..dfb936a 100644
--- a/model/Cargo.toml
+++ b/model/Cargo.toml
@@ -5,10 +5,18 @@ authors = ["Valentin Tolmer <valentin@tolmer.fr>", "Steve Barrau <steve.barrau@g
 edition = "2018"
 
 [features]
+default = ["opaque_server", "opaque_client"]
+opaque_server = []
+opaque_client = []
 js = []
 
 [dependencies]
+curve25519-dalek = "3"
+opaque-ke = "0.5"
+rand = "0.8"
 serde = "*"
+sha2 = "0.9"
+thiserror = "*"
 
 [dependencies.chrono]
 version = "*"
@@ -25,3 +33,11 @@ features = [
   "runtime-actix-native-tls",
   "sqlite",
 ]
+
+# For WASM targets, use the JS getrandom.
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies.getrandom]
+version = "0.2"
+features = ["js"]
+
+[target.'cfg(target_arch = "wasm32")'.dependencies.getrandom]
+version = "0.2"
diff --git a/model/src/lib.rs b/model/src/lib.rs
index c158e8d..d2b7d19 100644
--- a/model/src/lib.rs
+++ b/model/src/lib.rs
@@ -1,7 +1,9 @@
-use serde::{Deserialize, Serialize};
 use chrono::prelude::*;
+use serde::{Deserialize, Serialize};
 use std::collections::HashSet;
 
+pub mod opaque;
+
 #[derive(PartialEq, Eq, Debug, Serialize, Deserialize, Clone)]
 pub struct BindRequest {
     pub name: String,
diff --git a/model/src/opaque.rs b/model/src/opaque.rs
new file mode 100644
index 0000000..b4285e4
--- /dev/null
+++ b/model/src/opaque.rs
@@ -0,0 +1,159 @@
+use opaque_ke::ciphersuite::CipherSuite;
+use rand::{CryptoRng, RngCore};
+
+#[derive(thiserror::Error, Debug)]
+pub enum AuthenticationError {
+    #[error("Protocol error: `{0}`")]
+    ProtocolError(#[from] opaque_ke::errors::ProtocolError),
+}
+
+pub type AuthenticationResult<T> = std::result::Result<T, AuthenticationError>;
+
+/// The ciphersuite trait allows to specify the underlying primitives
+/// that will be used in the OPAQUE protocol
+#[allow(dead_code)]
+pub struct DefaultSuite;
+impl CipherSuite for DefaultSuite {
+    type Group = curve25519_dalek::ristretto::RistrettoPoint;
+    type KeyExchange = opaque_ke::key_exchange::tripledh::TripleDH;
+    type Hash = sha2::Sha512;
+    type SlowHash = opaque_ke::slow_hash::NoOpHash;
+}
+
+/// Client-side code for OPAQUE protocol handling, to register a new user and login.  All methods'
+/// results must be sent to the server using the serialized `.message`. Incoming messages can be
+/// deserialized using the type's `deserialize` method.
+#[cfg(feature = "opaque_client")]
+pub mod client {
+    use super::*;
+    /// Methods to register a new user, from the client side.
+    pub mod registration {
+        use super::*;
+        use opaque_ke::{
+            ClientRegistration, ClientRegistrationFinishParameters, ClientRegistrationFinishResult,
+            ClientRegistrationStartResult, RegistrationResponse,
+        };
+        /// Initiate the registration negotiation.
+        pub fn start_registration<R: RngCore + CryptoRng>(
+            password: &str,
+            rng: &mut R,
+        ) -> AuthenticationResult<ClientRegistrationStartResult<DefaultSuite>> {
+            Ok(ClientRegistration::<DefaultSuite>::start(
+                rng,
+                password.as_bytes(),
+            )?)
+        }
+
+        /// Finalize the registration negotiation.
+        pub fn finish_registration<R: RngCore + CryptoRng>(
+            registration_start: ClientRegistration<DefaultSuite>,
+            registration_response: RegistrationResponse<DefaultSuite>,
+            rng: &mut R,
+        ) -> AuthenticationResult<ClientRegistrationFinishResult<DefaultSuite>> {
+            Ok(registration_start.finish(
+                rng,
+                registration_response,
+                ClientRegistrationFinishParameters::default(),
+            )?)
+        }
+    }
+
+    /// Methods to login, from the client side.
+    pub mod login {
+        use super::*;
+        use opaque_ke::{
+            ClientLogin, ClientLoginFinishParameters, ClientLoginFinishResult,
+            ClientLoginStartParameters, ClientLoginStartResult, CredentialResponse,
+        };
+
+        /// Initiate the login negotiation.
+        pub fn start_login<R: RngCore + CryptoRng>(
+            password: &str,
+            rng: &mut R,
+        ) -> AuthenticationResult<ClientLoginStartResult<DefaultSuite>> {
+            Ok(ClientLogin::<DefaultSuite>::start(
+                rng,
+                password.as_bytes(),
+                ClientLoginStartParameters::default(),
+            )?)
+        }
+
+        /// Finalize the client login negotiation.
+        pub fn finish_login(
+            login_start: ClientLogin<DefaultSuite>,
+            login_response: CredentialResponse<DefaultSuite>,
+        ) -> AuthenticationResult<ClientLoginFinishResult<DefaultSuite>> {
+            Ok(login_start.finish(login_response, ClientLoginFinishParameters::default())?)
+        }
+    }
+}
+
+/// Server-side code for OPAQUE protocol handling, to register a new user and login.  The
+/// intermediate results must be sent to the client using the serialized `.message`.
+#[cfg(feature = "opaque_server")]
+pub mod server {
+    use super::*;
+    use opaque_ke::{keypair::Key, ServerRegistration};
+    /// Methods to register a new user, from the server side.
+    pub mod registration {
+        use super::*;
+        use opaque_ke::{RegistrationRequest, RegistrationUpload, ServerRegistrationStartResult};
+        /// Start a registration process, from a request sent by the client.
+        ///
+        /// The result must be kept for the next step.
+        pub fn start_registration<R: RngCore + CryptoRng>(
+            rng: &mut R,
+            registration_request: RegistrationRequest<DefaultSuite>,
+            server_public_key: &Key,
+        ) -> AuthenticationResult<ServerRegistrationStartResult<DefaultSuite>> {
+            Ok(ServerRegistration::<DefaultSuite>::start(
+                rng,
+                registration_request,
+                server_public_key,
+            )?)
+        }
+
+        /// Finish to register a new user, and get the data to store in the database.
+        pub fn get_password_file(
+            registration_start: ServerRegistration<DefaultSuite>,
+            registration_upload: RegistrationUpload<DefaultSuite>,
+        ) -> AuthenticationResult<ServerRegistration<DefaultSuite>> {
+            Ok(registration_start.finish(registration_upload)?)
+        }
+    }
+
+    /// Methods to handle user login, from the server-side.
+    pub mod login {
+        use super::*;
+        use opaque_ke::{
+            CredentialFinalization, CredentialRequest, ServerLogin, ServerLoginFinishResult,
+            ServerLoginStartParameters, ServerLoginStartResult,
+        };
+
+        /// Start a login process, from a request sent by the client.
+        ///
+        /// The result must be kept for the next step.
+        pub fn start_login<R: RngCore + CryptoRng>(
+            rng: &mut R,
+            password_file: ServerRegistration<DefaultSuite>,
+            server_private_key: &Key,
+            credential_request: CredentialRequest<DefaultSuite>,
+        ) -> AuthenticationResult<ServerLoginStartResult<DefaultSuite>> {
+            Ok(ServerLogin::start(
+                rng,
+                password_file,
+                server_private_key,
+                credential_request,
+                ServerLoginStartParameters::default(),
+            )?)
+        }
+
+        /// Finish to authorize a new user, and get the session key to decrypt associated data.
+        pub fn finalize_login(
+            login_start: ServerLogin<DefaultSuite>,
+            credential_finalization: CredentialFinalization<DefaultSuite>,
+        ) -> AuthenticationResult<ServerLoginFinishResult> {
+            Ok(login_start.finish(credential_finalization)?)
+        }
+    }
+}