Implement V2 key rotation support

.typos.toml

@@ -15,8 +15,10 @@ extend-ignore-re = [
     "(?i)helo_name",
     "Server name sent during.+HELO",
     # COSE Is short for CBOR Object Signing and Encryption, ignore these specific items
+    "COSE",
     "COSEKey",
     "COSEAlgorithm",
+    "CoseEncrypt0",
     # Ignore this specific string as it's valid
     "Ensure they are valid OTPs",
     # This word is misspelled upstream

Cargo.toml

@@ -107,7 +107,7 @@ serde = { version = "1.0.229", features = ["derive"] }
 serde_json = "1.0.151"
 
 # A safe, extensible ORM and Query builder
-diesel = { version = "2.3.13", features = ["chrono", "r2d2", "numeric"] }
+diesel = { version = "2.3.13", features = ["chrono", "r2d2", "numeric", "64-column-tables"] }
 diesel_migrations = "2.3.2"
 
 derive_more = { version = "2.1.1", features = [

migrations/mysql/2026-09-20-120000_user_crypto_v2/down.sql

@@ -0,0 +1,5 @@
+DROP TABLE IF EXISTS user_signature_key_pairs;
+
+ALTER TABLE users DROP COLUMN signed_public_key;
+ALTER TABLE users DROP COLUMN security_state;
+ALTER TABLE users DROP COLUMN security_version;

migrations/mysql/2026-09-20-120000_user_crypto_v2/up.sql

@@ -0,0 +1,14 @@
+ALTER TABLE users ADD COLUMN signed_public_key TEXT;
+ALTER TABLE users ADD COLUMN security_state TEXT;
+ALTER TABLE users ADD COLUMN security_version INTEGER;
+
+CREATE TABLE user_signature_key_pairs (
+    uuid                CHAR(36) NOT NULL PRIMARY KEY,
+    user_uuid           CHAR(36) NOT NULL UNIQUE,
+    signature_algorithm INTEGER  NOT NULL, -- 0 = ed25519, 1 = mldsa44
+    signing_key         TEXT     NOT NULL,
+    verifying_key       TEXT     NOT NULL,
+    created_at          DATETIME NOT NULL,
+    updated_at          DATETIME NOT NULL,
+    FOREIGN KEY (user_uuid) REFERENCES users (uuid) ON DELETE CASCADE
+);

migrations/mysql/2026-09-21-120000_add_v2_upgrade_token/down.sql

@@ -0,0 +1,2 @@
+ALTER TABLE users DROP COLUMN v2_upgrade_token;
+ALTER TABLE users_organizations DROP COLUMN v2_upgrade_token;

migrations/mysql/2026-09-21-120000_add_v2_upgrade_token/up.sql

@@ -0,0 +1,2 @@
+ALTER TABLE users ADD COLUMN v2_upgrade_token TEXT;
+ALTER TABLE users_organizations ADD COLUMN v2_upgrade_token TEXT;

migrations/postgresql/2026-09-20-120000_user_crypto_v2/down.sql

@@ -0,0 +1,5 @@
+DROP TABLE IF EXISTS user_signature_key_pairs;
+
+ALTER TABLE users DROP COLUMN signed_public_key;
+ALTER TABLE users DROP COLUMN security_state;
+ALTER TABLE users DROP COLUMN security_version;

migrations/postgresql/2026-09-20-120000_user_crypto_v2/up.sql

@@ -0,0 +1,13 @@
+ALTER TABLE users ADD COLUMN signed_public_key TEXT;
+ALTER TABLE users ADD COLUMN security_state TEXT;
+ALTER TABLE users ADD COLUMN security_version INTEGER;
+
+CREATE TABLE user_signature_key_pairs (
+    uuid                CHAR(36) NOT NULL PRIMARY KEY,
+    user_uuid           CHAR(36) NOT NULL UNIQUE REFERENCES users (uuid) ON DELETE CASCADE,
+    signature_algorithm INTEGER  NOT NULL, -- 0 = ed25519, 1 = mldsa44
+    signing_key         TEXT     NOT NULL,
+    verifying_key       TEXT     NOT NULL,
+    created_at          TIMESTAMP NOT NULL,
+    updated_at          TIMESTAMP NOT NULL
+);

migrations/postgresql/2026-09-21-120000_add_v2_upgrade_token/down.sql

@@ -0,0 +1,2 @@
+ALTER TABLE users DROP COLUMN v2_upgrade_token;
+ALTER TABLE users_organizations DROP COLUMN v2_upgrade_token;

migrations/postgresql/2026-09-21-120000_add_v2_upgrade_token/up.sql

@@ -0,0 +1,2 @@
+ALTER TABLE users ADD COLUMN v2_upgrade_token TEXT;
+ALTER TABLE users_organizations ADD COLUMN v2_upgrade_token TEXT;

migrations/sqlite/2026-09-20-120000_user_crypto_v2/down.sql

@@ -0,0 +1,5 @@
+DROP TABLE IF EXISTS user_signature_key_pairs;
+
+ALTER TABLE users DROP COLUMN signed_public_key;
+ALTER TABLE users DROP COLUMN security_state;
+ALTER TABLE users DROP COLUMN security_version;

migrations/sqlite/2026-09-20-120000_user_crypto_v2/up.sql

@@ -0,0 +1,13 @@
+ALTER TABLE users ADD COLUMN signed_public_key TEXT;
+ALTER TABLE users ADD COLUMN security_state TEXT;
+ALTER TABLE users ADD COLUMN security_version INTEGER;
+
+CREATE TABLE user_signature_key_pairs (
+    uuid                TEXT     NOT NULL PRIMARY KEY,
+    user_uuid           TEXT     NOT NULL UNIQUE REFERENCES users (uuid) ON DELETE CASCADE,
+    signature_algorithm INTEGER  NOT NULL, -- 0 = ed25519, 1 = mldsa44
+    signing_key         TEXT     NOT NULL,
+    verifying_key       TEXT     NOT NULL,
+    created_at          DATETIME NOT NULL,
+    updated_at          DATETIME NOT NULL
+);

migrations/sqlite/2026-09-21-120000_add_v2_upgrade_token/down.sql

@@ -0,0 +1,2 @@
+ALTER TABLE users DROP COLUMN v2_upgrade_token;
+ALTER TABLE users_organizations DROP COLUMN v2_upgrade_token;

migrations/sqlite/2026-09-21-120000_add_v2_upgrade_token/up.sql

@@ -0,0 +1,2 @@
+ALTER TABLE users ADD COLUMN v2_upgrade_token TEXT;
+ALTER TABLE users_organizations ADD COLUMN v2_upgrade_token TEXT;

src/api/core/ciphers.rs

@@ -197,11 +197,14 @@ async fn sync(data: SyncData, headers: Headers, client_version: Option<ClientVer
         Value::Null
     };
 
-    // Upstream omits this when unset rather than sending null.
+    // Upstream omits these two when unset rather than sending null.
     let mut user_decryption = json!({ "masterPasswordUnlock": master_password_unlock });
     if let Some(key_id) = &headers.user.key_id {
         user_decryption["userKeyId"] = json!(key_id);
     }
+    if let Some(v2_upgrade_token) = headers.user.v2_upgrade_token_json() {
+        user_decryption["v2UpgradeToken"] = v2_upgrade_token;
+    }
 
     Ok(Json(json!({
         "profile": user_json,

src/api/identity.rs

@@ -560,18 +560,7 @@ async fn authenticated_response(
         Value::Null
     };
 
-    let account_keys = if user.private_key.is_some() {
-        json!({
-            "publicKeyEncryptionKeyPair": {
-                "wrappedPrivateKey": user.private_key,
-                "publicKey": user.public_key,
-                "Object": "publicKeyEncryptionKeyPair"
-            },
-            "Object": "privateKeys"
-        })
-    } else {
-        Value::Null
-    };
+    let account_keys = user.account_keys_json(conn).await;
 
     let mut result = json!({
         "access_token": auth_tokens.access_token(),
@@ -711,18 +700,7 @@ async fn user_api_key_login(
         Value::Null
     };
 
-    let account_keys = if user.private_key.is_some() {
-        json!({
-            "publicKeyEncryptionKeyPair": {
-                "wrappedPrivateKey": user.private_key,
-                "publicKey": user.public_key,
-                "Object": "publicKeyEncryptionKeyPair"
-            },
-            "Object": "privateKeys"
-        })
-    } else {
-        Value::Null
-    };
+    let account_keys = user.account_keys_json(conn).await;
 
     // Note: No refresh_token is returned. The CLI just repeats the
     // client_credentials login flow when the existing token expires.

src/api/mod.rs

@@ -23,7 +23,7 @@ pub use crate::api::{
     icons::routes as icons_routes,
     identity::routes as identity_routes,
     notifications::routes as notifications_routes,
-    notifications::{AnonymousNotify, Notify, UpdateType, WS_ANONYMOUS_SUBSCRIPTIONS, WS_USERS},
+    notifications::{AnonymousNotify, LogOutReason, Notify, UpdateType, WS_ANONYMOUS_SUBSCRIPTIONS, WS_USERS},
     push::{
         push_cipher_update, push_folder_update, push_logout, push_send_update, push_user_update, register_push_device,
         unregister_push_device,

src/api/notifications.rs

@@ -383,23 +383,36 @@ impl WebSocketUsers {
     }
 
     pub async fn send_logout(&self, user: &User, acting_device: Option<&Device>, conn: &DbConn) {
+        self.send_logout_with_reason(user, acting_device, None, conn).await;
+    }
+
+    /// A logout that clients may handle differently depending on `reason`, e.g. syncing instead of
+    /// logging out after a key rotation that kept the sessions alive.
+    pub async fn send_logout_with_reason(
+        &self,
+        user: &User,
+        acting_device: Option<&Device>,
+        reason: Option<LogOutReason>,
+        conn: &DbConn,
+    ) {
         // Skip any processing if both WebSockets and Push are not active
         if *NOTIFICATIONS_DISABLED {
             return;
         }
         let acting_device_id = acting_device.map(|d| d.uuid.clone());
-        let data = create_update(
-            vec![("UserId".into(), user.uuid.to_string().into()), ("Date".into(), serialize_date(user.updated_at))],
-            UpdateType::LogOut,
-            acting_device_id,
-        );
+        let mut payload =
+            vec![("UserId".into(), user.uuid.to_string().into()), ("Date".into(), serialize_date(user.updated_at))];
+        if let Some(reason) = reason {
+            payload.push(("Reason".into(), (reason as i32).into()));
+        }
+        let data = create_update(payload, UpdateType::LogOut, acting_device_id);
 
         if CONFIG.enable_websocket() {
             self.send_update(&user.uuid, &data).await;
         }
 
         if CONFIG.push_enabled() {
-            push_logout(user, acting_device, conn).await;
+            push_logout(user, acting_device, reason, conn).await;
         }
     }
 
@@ -667,6 +680,15 @@ fn create_ping() -> Vec<u8> {
     serialize(&Value::Array(vec![6.into()]))
 }
 
+/// Why a logout was pushed. Absent for a plain logout.
+///
+/// Ref: <https://github.com/bitwarden/server/blob/main/src/Core/Enums/PushNotificationLogOutReason.cs>
+/// (`KdfChange = 0` is not sent by vaultwarden yet.)
+#[derive(Copy, Clone, Eq, PartialEq)]
+pub enum LogOutReason {
+    KeyRotation = 1,
+}
+
 // https://github.com/bitwarden/server/blob/375af7c43b10d9da03525d41452f95de3f921541/src/Core/Enums/PushType.cs
 #[derive(Copy, Clone, Eq, PartialEq)]
 pub enum UpdateType {

src/api/push.rs

@@ -12,7 +12,7 @@ use tokio::sync::RwLock;
 
 use crate::{
     CONFIG,
-    api::{ApiResult, EmptyResult, UpdateType},
+    api::{ApiResult, EmptyResult, LogOutReason, UpdateType},
     db::{
         DbConn,
         models::{AuthRequestId, Cipher, Device, Folder, PushId, Send, User, UserId},
@@ -188,7 +188,7 @@ pub async fn push_cipher_update(ut: UpdateType, cipher: &Cipher, device: &Device
     }
 }
 
-pub async fn push_logout(user: &User, acting_device: Option<&Device>, conn: &DbConn) {
+pub async fn push_logout(user: &User, acting_device: Option<&Device>, reason: Option<LogOutReason>, conn: &DbConn) {
     if Device::check_user_has_push_device(&user.uuid, conn).await {
         tokio::task::spawn(send_to_push_relay(json!({
             "userId": user.uuid,
@@ -198,7 +198,8 @@ pub async fn push_logout(user: &User, acting_device: Option<&Device>, conn: &DbC
             "type": UpdateType::LogOut as i32,
             "payload": {
                 "userId": user.uuid,
-                "date": format_date(&user.updated_at)
+                "date": format_date(&user.updated_at),
+                "reason": reason.map(|r| r as i32),
             },
             "clientType": null,
             "installationId": null

src/auth.rs

@@ -30,7 +30,7 @@ use crate::{
         models::{
             AttachmentId, CipherId, Collection, CollectionId, Device, DeviceId, DeviceType, EmergencyAccessId,
             EventType, Membership, MembershipId, MembershipStatus, MembershipType, OrgApiKeyId, OrganizationId,
-            SendFileId, SendId, User, UserId, UserStampException,
+            SendFileId, SendId, User, UserId,
         },
     },
     error::Error,
@@ -667,31 +667,13 @@ impl<'r> FromRequest<'r> for Headers {
         };
 
         if user.security_stamp != claims.sstamp {
-            if let Some(stamp_exception) =
-                user.stamp_exception.as_deref().and_then(|s| serde_json::from_str::<UserStampException>(s).ok())
-            {
-                let Some(current_route) = request.route().and_then(|r| r.name.as_deref()) else {
-                    err_handler!("Error getting current route for stamp exception")
-                };
+            let Some(current_route) = request.route().and_then(|r| r.name.as_deref()) else {
+                err_handler!("Error getting current route for stamp exception")
+            };
 
-                // Check if the stamp exception has expired first.
-                // Then, check if the current route matches any of the allowed routes.
-                // After that check the stamp in exception matches the one in the claims.
-                if Utc::now().timestamp() > stamp_exception.expire {
-                    // If the stamp exception has been expired remove it from the database.
-                    // This prevents checking this stamp exception for new requests.
-                    let mut user = user;
-                    user.reset_stamp_exception();
-                    if let Err(e) = user.save(&conn).await {
-                        error!("Error updating user: {e:#?}");
-                    }
-                    err_handler!("Stamp exception is expired")
-                } else if !stamp_exception.routes.contains(&current_route.to_owned()) {
-                    err_handler!("Invalid security stamp: Current route and exception route do not match")
-                } else if stamp_exception.security_stamp != claims.sstamp {
-                    err_handler!("Invalid security stamp for matched stamp exception")
-                }
-            } else {
+            // Expired exceptions are dropped the next time the stamp is reset, not here: writing them
+            // back from this request could undo a reset made since the user was read.
+            if !user.stamp_exceptions().iter().any(|e| e.allows(&claims.sstamp, current_route)) {
                 err_handler!("Invalid security stamp")
             }
         }

src/config.rs

@@ -1434,6 +1434,11 @@ pub const SUPPORTED_FEATURE_FLAGS: &[&str] = &[
     "ssh-key-vault-item",
     "pm-25373-windows-biometrics-v2",
     "pm-26340-linux-biometrics-v2",
+    "pm-31050-no-logout-key-upgrade-rotation",
+    "pm-27278-v2-password-registration",
+    "enable-account-encryption-v2-jit-password-registration",
+    "pm-30144-sdk-key-rotation",
+    "force-upgrade-v2-encryption",
     // Mobile Team
     "anon-addy-self-host-alias",
     "simple-login-self-host-alias",

src/db/models/mod.rs

@@ -17,6 +17,7 @@ mod two_factor;
 mod two_factor_duo_context;
 mod two_factor_incomplete;
 mod user;
+mod user_signature_key_pair;
 
 pub use self::archive::Archive;
 pub use self::attachment::{Attachment, AttachmentId};
@@ -39,4 +40,5 @@ pub use self::sso_auth::{OIDCAuthenticatedUser, OIDCCodeResponseError, SsoAuth};
 pub use self::two_factor::{TwoFactor, TwoFactorType};
 pub use self::two_factor_duo_context::TwoFactorDuoContext;
 pub use self::two_factor_incomplete::TwoFactorIncomplete;
-pub use self::user::{Invitation, KeyId, SsoUser, User, UserId, UserKdfType, UserStampException};
+pub use self::user::{Invitation, KeyId, SsoUser, User, UserId, UserKdfType};
+pub use self::user_signature_key_pair::{SignatureAlgorithm, UserSignatureKeyPair};

src/db/models/organization.rs

@@ -54,6 +54,10 @@ pub struct Membership {
     pub atype: i32,
     pub reset_password_key: Option<String>,
     pub external_id: Option<String>,
+    /// A copy of the user's v2 upgrade token, kept when a v1 -> v2 upgrade leaves the account
+    /// recovery key (`reset_password_key`) wrapped by the v1 user key. It lets the organization
+    /// unwrap the v2 user key from it. Opaque to us, like `User::v2_upgrade_token`.
+    pub v2_upgrade_token: Option<String>,
 }
 
 #[derive(Identifiable, Queryable, Insertable, AsChangeset)]
@@ -271,6 +275,7 @@ impl Membership {
             atype: MembershipType::User as i32,
             reset_password_key: None,
             external_id: None,
+            v2_upgrade_token: None,
         }
     }
 

src/db/models/user.rs

@@ -6,6 +6,7 @@ use serde_json::Value;
 use crate::{
     CONFIG,
     api::EmptyResult,
+    auth::DEFAULT_ACCESS_VALIDITY,
     crypto,
     db::{
         DbConn,
@@ -20,6 +21,7 @@ use macros::UuidFromParam;
 
 use super::{
     Cipher, Device, EmergencyAccess, Favorite, Folder, Membership, MembershipType, TwoFactor, TwoFactorIncomplete,
+    UserSignatureKeyPair,
 };
 
 #[derive(Identifiable, Queryable, Insertable, AsChangeset, Selectable)]
@@ -71,6 +73,15 @@ pub struct User {
     pub external_id: Option<String>, // Todo: Needs to be removed in the future, this is not used anymore.
 
     pub key_id: Option<KeyId>,
+
+    // "v2" account cryptographic state. Either all of these are set (together with a row in
+    // `user_signature_key_pairs`) or none of them are; see `User::is_v2`.
+    pub signed_public_key: Option<String>,
+    pub security_state: Option<String>,
+    pub security_version: Option<i32>,
+    /// JSON `{"wrappedUserKey1": ..., "wrappedUserKey2": ...}`, letting clients that still hold the
+    /// v1 user key obtain the v2 one after another client performed the upgrade. Opaque to us.
+    pub v2_upgrade_token: Option<String>,
 }
 
 #[derive(Identifiable, Queryable, Insertable)]
@@ -99,13 +110,28 @@ enum UserStatus {
     _Disabled = 2,
 }
 
+/// A previous security stamp that is still accepted, until `expire`.
 #[derive(Serialize, Deserialize)]
 pub struct UserStampException {
-    pub routes: Vec<String>,
+    /// The routes the stamp is still accepted on, or `None` for any route.
+    pub routes: Option<Vec<String>>,
     pub security_stamp: String,
     pub expire: i64,
 }
 
+impl UserStampException {
+    pub fn is_expired(&self) -> bool {
+        Utc::now().timestamp() > self.expire
+    }
+
+    /// Whether this exception lets a token carrying `security_stamp` through on `route`.
+    pub fn allows(&self, security_stamp: &str, route: &str) -> bool {
+        !self.is_expired()
+            && self.security_stamp == security_stamp
+            && self.routes.as_ref().is_none_or(|routes| routes.iter().any(|r| r == route))
+    }
+}
+
 /// Local methods
 impl User {
     pub const CLIENT_KDF_TYPE_DEFAULT: i32 = UserKdfType::Pbkdf2 as i32;
@@ -158,9 +184,18 @@ impl User {
             external_id: None, // Todo: Needs to be removed in the future, this is not used anymore.
 
             key_id: None,
+
+            signed_public_key: None,
+            security_state: None,
+            security_version: None,
+            v2_upgrade_token: None,
         }
     }
 
+    pub fn is_v2(&self) -> bool {
+        self.signed_public_key.is_some() && self.security_state.is_some() && self.security_version.is_some()
+    }
+
     pub fn check_valid_password(&self, password: &str) -> bool {
         crypto::verify_password_hash(
             password.as_bytes(),
@@ -220,10 +255,41 @@ impl User {
 
     pub async fn reset_security_stamp(&mut self, conn: &DbConn) -> EmptyResult {
         self.security_stamp = get_uuid();
+        // A reset is meant to end the other sessions, which a key rotation's grace would undo. The
+        // route exceptions stay, since they are set right before a reset, for the stamp it replaces.
+        // This is also where expired exceptions get dropped.
+        let mut exceptions = self.stamp_exceptions();
+        exceptions.retain(|e| e.routes.is_some() && !e.is_expired());
+        self.set_stamp_exceptions(&exceptions);
         Device::rotate_refresh_tokens_by_user(&self.uuid, conn).await?;
         Ok(())
     }
 
+    /// Resets the security stamp after a key rotation, while letting the access tokens already
+    /// issued keep working until they expire.
+    ///
+    /// This is what upstream does: there the stamp is only checked when a token is refreshed, so a
+    /// rotation invalidates refresh tokens but not the access tokens in use. Clients rely on it to
+    /// keep a session going across a rotation. Chained rotations keep every earlier stamp that is
+    /// still within its window.
+    pub async fn reset_security_stamp_after_key_rotation(&mut self, conn: &DbConn) -> EmptyResult {
+        let previous_stamp = self.security_stamp.clone();
+        let mut grace: Vec<UserStampException> =
+            self.stamp_exceptions().into_iter().filter(|e| e.routes.is_none() && !e.is_expired()).collect();
+
+        self.reset_security_stamp(conn).await?;
+
+        grace.push(UserStampException {
+            routes: None,
+            security_stamp: previous_stamp,
+            expire: (Utc::now() + *DEFAULT_ACCESS_VALIDITY).timestamp(),
+        });
+        let mut exceptions = self.stamp_exceptions();
+        exceptions.extend(grace);
+        self.set_stamp_exceptions(&exceptions);
+        Ok(())
+    }
+
     /// Set the stamp_exception to only allow a subsequent request matching a specific route using the current security-stamp.
     ///
     /// # Arguments
@@ -232,17 +298,30 @@ impl User {
     ///   After these 2 minutes this stamp will expire.
     ///
     pub fn set_stamp_exception(&mut self, route_exception: Vec<String>) {
-        let stamp_exception = UserStampException {
-            routes: route_exception,
+        self.set_stamp_exceptions(&[UserStampException {
+            routes: Some(route_exception),
             security_stamp: self.security_stamp.clone(),
             expire: (Utc::now() + TimeDelta::try_minutes(2).unwrap()).timestamp(),
-        };
-        self.stamp_exception = Some(serde_json::to_string(&stamp_exception).unwrap_or_default());
+        }]);
     }
 
-    /// Resets the stamp_exception to prevent re-use of the previous security-stamp
-    pub fn reset_stamp_exception(&mut self) {
-        self.stamp_exception = None;
+    /// The previous security stamps that are still accepted, expired ones included.
+    pub fn stamp_exceptions(&self) -> Vec<UserStampException> {
+        let Some(stored) = self.stamp_exception.as_deref() else {
+            return Vec::new();
+        };
+        // Before key rotations kept sessions alive, only a single route exception was stored.
+        serde_json::from_str::<Vec<UserStampException>>(stored)
+            .or_else(|_| serde_json::from_str::<UserStampException>(stored).map(|e| vec![e]))
+            .unwrap_or_default()
+    }
+
+    fn set_stamp_exceptions(&mut self, exceptions: &[UserStampException]) {
+        self.stamp_exception = if exceptions.is_empty() {
+            None
+        } else {
+            Some(serde_json::to_string(&exceptions).unwrap_or_default())
+        };
     }
 
     pub fn display_name(&self) -> &str {
@@ -257,6 +336,61 @@ impl User {
 
 /// Database methods
 impl User {
+    async fn v2_signature_key_pair(&self, conn: &DbConn) -> Option<UserSignatureKeyPair> {
+        if !self.is_v2() {
+            return None;
+        }
+        UserSignatureKeyPair::find_by_user(&self.uuid, conn).await
+    }
+
+    pub async fn account_keys_json(&self, conn: &DbConn) -> Value {
+        if self.private_key.is_none() {
+            return Value::Null;
+        }
+
+        let (signed_public_key, signature_key_pair, security_state) = match self.v2_signature_key_pair(conn).await {
+            Some(key_pair) => (
+                json!(self.signed_public_key),
+                key_pair.to_json(),
+                json!({
+                    "securityState": self.security_state,
+                    "securityVersion": self.security_version,
+                }),
+            ),
+            None => (Value::Null, Value::Null, Value::Null),
+        };
+
+        json!({
+            "publicKeyEncryptionKeyPair": {
+                "wrappedPrivateKey": self.private_key,
+                "publicKey": self.public_key,
+                "signedPublicKey": signed_public_key,
+                "object": "publicKeyEncryptionKeyPair",
+            },
+            "signatureKeyPair": signature_key_pair,
+            "securityState": security_state,
+            "object": "privateKeys"
+        })
+    }
+
+    pub async fn public_keys_json(&self, conn: &DbConn) -> Value {
+        let (signed_public_key, verifying_key) = match self.v2_signature_key_pair(conn).await {
+            Some(key_pair) => (json!(self.signed_public_key), json!(key_pair.verifying_key)),
+            None => (Value::Null, Value::Null),
+        };
+
+        json!({
+            "publicKey": self.public_key,
+            "signedPublicKey": signed_public_key,
+            "verifyingKey": verifying_key,
+            "object": "publicKeys"
+        })
+    }
+
+    pub fn v2_upgrade_token_json(&self) -> Option<Value> {
+        self.v2_upgrade_token.as_ref().and_then(|token| serde_json::from_str(token).ok())
+    }
+
     pub async fn to_json(&self, conn: &DbConn) -> Value {
         let mut orgs_json = Vec::new();
         for c in Membership::find_confirmed_by_user(&self.uuid, conn).await {
@@ -277,21 +411,7 @@ impl User {
             UserStatus::Enabled
         };
 
-        let account_keys = if self.private_key.is_some() {
-            json!({
-                "publicKeyEncryptionKeyPair": {
-                    "wrappedPrivateKey": self.private_key,
-                    "publicKey": self.public_key,
-                    "signedPublicKey": null,
-                    "object": "publicKeyEncryptionKeyPair",
-                },
-                "securityState": null,
-                "signatureKeyPair": null,
-                "object": "privateKeys"
-            })
-        } else {
-            Value::Null
-        };
+        let account_keys = self.account_keys_json(conn).await;
 
         json!({
             "_status": status as i32,
@@ -367,6 +487,7 @@ impl User {
         Device::delete_all_by_user(&self.uuid, conn).await?;
         TwoFactor::delete_all_by_user(&self.uuid, conn).await?;
         TwoFactorIncomplete::delete_all_by_user(&self.uuid, conn).await?;
+        UserSignatureKeyPair::delete_all_by_user(&self.uuid, conn).await?;
         Invitation::take(&self.email, conn).await; // Delete invitation if any
 
         conn.run(move |conn| {

src/db/models/user_signature_key_pair.rs

@@ -0,0 +1,137 @@
+use chrono::{NaiveDateTime, Utc};
+use derive_more::{AsRef, Deref, Display, From};
+use diesel::prelude::*;
+use serde_json::Value;
+
+use crate::{
+    api::EmptyResult,
+    db::{DbConn, schema::user_signature_key_pairs},
+    error::MapResult,
+    util::get_uuid,
+};
+
+use super::UserId;
+
+/// A user's signature key pair, part of the "v2" account cryptographic state.
+///
+/// Upstream keeps this in its own table rather than as columns on the user, with a unique index on
+/// the user id. The stated intent is to eventually keep superseded key pairs around (an `active`
+/// flag was sketched but not shipped), which is why this is modelled as a row with its own identity
+/// instead of a set of user attributes.
+///
+/// Ref: <https://github.com/bitwarden/server/blob/main/src/Sql/dbo/KeyManagement/Tables/UserSignatureKeyPair.sql>
+#[derive(Identifiable, Queryable, Insertable, AsChangeset, Selectable)]
+#[diesel(table_name = user_signature_key_pairs)]
+#[diesel(treat_none_as_null = true)]
+#[diesel(primary_key(uuid))]
+pub struct UserSignatureKeyPair {
+    pub uuid: UserSignatureKeyPairId,
+    pub user_uuid: UserId,
+
+    pub signature_algorithm: i32,
+    /// The signing (private) key, wrapped by the user key.
+    pub signing_key: String,
+    /// The COSE-encoded public verifying key.
+    pub verifying_key: String,
+
+    pub created_at: NaiveDateTime,
+    pub updated_at: NaiveDateTime,
+}
+
+/// https://github.com/bitwarden/server/blob/main/src/Core/KeyManagement/Enums/SignatureAlgorithm.cs
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum SignatureAlgorithm {
+    Ed25519 = 0,
+    MlDsa44 = 1,
+}
+
+impl SignatureAlgorithm {
+    pub fn parse(algorithm: &str) -> Option<Self> {
+        match algorithm {
+            "ed25519" => Some(Self::Ed25519),
+            "mldsa44" => Some(Self::MlDsa44),
+            _ => None,
+        }
+    }
+}
+
+/// Local methods
+impl UserSignatureKeyPair {
+    pub fn new(
+        user_uuid: UserId,
+        signature_algorithm: SignatureAlgorithm,
+        signing_key: String,
+        verifying_key: String,
+    ) -> Self {
+        let now = Utc::now().naive_utc();
+
+        Self {
+            uuid: UserSignatureKeyPairId(get_uuid()),
+            user_uuid,
+            signature_algorithm: signature_algorithm as i32,
+            signing_key,
+            verifying_key,
+            created_at: now,
+            updated_at: now,
+        }
+    }
+
+    pub fn to_json(&self) -> Value {
+        json!({
+            "wrappedSigningKey": self.signing_key,
+            "verifyingKey": self.verifying_key,
+            "object": "signatureKeyPair",
+        })
+    }
+}
+
+/// Database methods
+impl UserSignatureKeyPair {
+    pub async fn save(&mut self, conn: &DbConn) -> EmptyResult {
+        self.updated_at = Utc::now().naive_utc();
+
+        db_run! { conn:
+            mysql {
+                diesel::insert_into(user_signature_key_pairs::table)
+                    .values(&*self)
+                    .on_conflict(diesel::dsl::DuplicatedKeys)
+                    .do_update()
+                    .set(&*self)
+                    .execute(conn)
+                    .map_res("Error saving user signature key pair")
+            }
+            postgresql, sqlite {
+                diesel::insert_into(user_signature_key_pairs::table)
+                    .values(&*self)
+                    .on_conflict(user_signature_key_pairs::user_uuid)
+                    .do_update()
+                    .set(&*self)
+                    .execute(conn)
+                    .map_res("Error saving user signature key pair")
+            }
+        }
+    }
+
+    /// The user's key pair. There is at most one, enforced by a unique index on `user_uuid`.
+    pub async fn find_by_user(user_uuid: &UserId, conn: &DbConn) -> Option<Self> {
+        conn.run(move |conn| {
+            user_signature_key_pairs::table
+                .filter(user_signature_key_pairs::user_uuid.eq(user_uuid))
+                .first::<Self>(conn)
+                .ok()
+        })
+        .await
+    }
+
+    pub async fn delete_all_by_user(user_uuid: &UserId, conn: &DbConn) -> EmptyResult {
+        conn.run(move |conn| {
+            diesel::delete(user_signature_key_pairs::table.filter(user_signature_key_pairs::user_uuid.eq(user_uuid)))
+                .execute(conn)
+                .map_res("Error deleting user signature key pairs")
+        })
+        .await
+    }
+}
+
+#[derive(Clone, Debug, AsRef, Deref, DieselNewType, Display, From, Hash, PartialEq, Eq, Serialize, Deserialize)]
+pub struct UserSignatureKeyPairId(String);

src/db/schema.rs

@@ -218,6 +218,22 @@ table! {
         avatar_color -> Nullable<Text>,
         external_id -> Nullable<Text>,
         key_id -> Nullable<Text>,
+        signed_public_key -> Nullable<Text>,
+        security_state -> Nullable<Text>,
+        security_version -> Nullable<Integer>,
+        v2_upgrade_token -> Nullable<Text>,
+    }
+}
+
+table! {
+    user_signature_key_pairs (uuid) {
+        uuid -> Text,
+        user_uuid -> Text,
+        signature_algorithm -> Integer,
+        signing_key -> Text,
+        verifying_key -> Text,
+        created_at -> Timestamp,
+        updated_at -> Timestamp,
     }
 }
 
@@ -243,6 +259,7 @@ table! {
         atype -> Integer,
         reset_password_key -> Nullable<Text>,
         external_id -> Nullable<Text>,
+        v2_upgrade_token -> Nullable<Text>,
     }
 }
 
@@ -383,6 +400,7 @@ joinable!(collections_groups -> groups (groups_uuid));
 joinable!(event -> users_organizations (uuid));
 joinable!(auth_requests -> users (user_uuid));
 joinable!(sso_users -> users (user_uuid));
+joinable!(user_signature_key_pairs -> users (user_uuid));
 
 allow_tables_to_appear_in_same_query!(
     archives,
@@ -409,4 +427,5 @@ allow_tables_to_appear_in_same_query!(
     collections_groups,
     event,
     auth_requests,
+    user_signature_key_pairs,
 );