diff --git a/src/handlers/accounts.rs b/src/handlers/accounts.rs
index 62ab338..5d7b3c9 100644
--- a/src/handlers/accounts.rs
+++ b/src/handlers/accounts.rs
@@ -1,17 +1,23 @@
 use axum::{extract::State, Json};
 use chrono::Utc;
-use constant_time_eq::constant_time_eq;
 use serde_json::{json, Value};
 use std::sync::Arc;
 use uuid::Uuid;
-use worker::{query, Env};
+use worker::{query, D1PreparedStatement, Env};
 
+use super::get_batch_size;
 use crate::{
     auth::Claims,
-    crypto::{generate_salt, hash_password_for_storage, verify_password},
+    crypto::{generate_salt, hash_password_for_storage},
     db,
     error::AppError,
-    models::user::{DeleteAccountRequest, PreloginResponse, RegisterRequest, User},
+    models::{
+        cipher::CipherData,
+        user::{
+            ChangePasswordRequest, DeleteAccountRequest, PreloginResponse, RegisterRequest,
+            RotateKeyRequest, User,
+        },
+    },
 };
 
 #[worker::send]
@@ -119,22 +125,22 @@ pub async fn revision_date(
     claims: Claims,
     State(env): State<Arc<Env>>,
 ) -> Result<Json<i64>, AppError> {
-    let db = db::get_db(&env)? ;
-    
+    let db = db::get_db(&env)?;
+
     // get the user's updated_at timestamp
     let updated_at: Option<String> = db
         .prepare("SELECT updated_at FROM users WHERE id = ?1")
-        .bind(&[claims.sub. into()])?
+        .bind(&[claims.sub.into()])?
         .first(Some("updated_at"))
         .await
         .map_err(|_| AppError::Database)?;
-        
+
     // convert the timestamp to a millisecond-level Unix timestamp
     let revision_date = updated_at
-        .and_then(|ts| chrono::DateTime::parse_from_rfc3339(&ts). ok())
-        . map(|dt| dt.timestamp_millis())
+        .and_then(|ts| chrono::DateTime::parse_from_rfc3339(&ts).ok())
+        .map(|dt| dt.timestamp_millis())
         .unwrap_or_else(|| chrono::Utc::now().timestamp_millis());
-    
+
     Ok(Json(revision_date))
 }
 
@@ -162,18 +168,9 @@ pub async fn delete_account(
         .master_password_hash
         .ok_or_else(|| AppError::BadRequest("Missing master password hash".to_string()))?;
 
-    let is_valid = if let Some(ref salt) = user.password_salt {
-        // New user with PBKDF2 hashed password
-        verify_password(&provided_hash, &user.master_password_hash, salt).await?
-    } else {
-        // Legacy user: direct comparison (migration happens at login, not delete)
-        constant_time_eq(
-            user.master_password_hash.as_bytes(),
-            provided_hash.as_bytes(),
-        )
-    };
+    let verification = user.verify_master_password(&provided_hash).await?;
 
-    if !is_valid {
+    if !verification.is_valid() {
         return Err(AppError::Unauthorized("Invalid password".to_string()));
     }
 
@@ -197,3 +194,183 @@ pub async fn delete_account(
 
     Ok(Json(json!({})))
 }
+
+/// POST /accounts/password - Change master password
+#[worker::send]
+pub async fn post_password(
+    claims: Claims,
+    State(env): State<Arc<Env>>,
+    Json(payload): Json<ChangePasswordRequest>,
+) -> Result<Json<Value>, AppError> {
+    let db = db::get_db(&env)?;
+    let user_id = &claims.sub;
+
+    // Get the user from the database
+    let user: Value = db
+        .prepare("SELECT * FROM users WHERE id = ?1")
+        .bind(&[user_id.clone().into()])?
+        .first(None)
+        .await
+        .map_err(|_| AppError::Database)?
+        .ok_or_else(|| AppError::NotFound("User not found".to_string()))?;
+    let user: User = serde_json::from_value(user).map_err(|_| AppError::Internal)?;
+
+    // Verify the current master password
+    let verification = user
+        .verify_master_password(&payload.master_password_hash)
+        .await?;
+
+    if !verification.is_valid() {
+        return Err(AppError::Unauthorized("Invalid password".to_string()));
+    }
+
+    // Generate new salt and hash the new password
+    let new_salt = generate_salt()?;
+    let new_hashed_password =
+        hash_password_for_storage(&payload.new_master_password_hash, &new_salt).await?;
+
+    // Generate new security stamp and update timestamp
+    let new_security_stamp = Uuid::new_v4().to_string();
+    let now = Utc::now().to_rfc3339();
+
+    // Update user record
+    query!(
+        &db,
+        "UPDATE users SET master_password_hash = ?1, password_salt = ?2, key = ?3, master_password_hint = ?4, security_stamp = ?5, updated_at = ?6 WHERE id = ?7",
+        new_hashed_password,
+        new_salt,
+        payload.key,
+        payload.master_password_hint,
+        new_security_stamp,
+        now,
+        user_id
+    )
+    .map_err(|_| AppError::Database)?
+    .run()
+    .await?;
+
+    Ok(Json(json!({})))
+}
+
+/// POST /accounts/key-management/rotate-user-account-keys - Rotate user encryption keys
+#[worker::send]
+pub async fn post_rotatekey(
+    claims: Claims,
+    State(env): State<Arc<Env>>,
+    Json(payload): Json<RotateKeyRequest>,
+) -> Result<Json<Value>, AppError> {
+    let db = db::get_db(&env)?;
+    let user_id = &claims.sub;
+    let batch_size = get_batch_size(&env);
+
+    // Get the user from the database
+    let user: Value = db
+        .prepare("SELECT * FROM users WHERE id = ?1")
+        .bind(&[user_id.clone().into()])?
+        .first(None)
+        .await
+        .map_err(|_| AppError::Database)?
+        .ok_or_else(|| AppError::NotFound("User not found".to_string()))?;
+    let user: User = serde_json::from_value(user).map_err(|_| AppError::Internal)?;
+
+    // Verify the current master password
+    let verification = user
+        .verify_master_password(&payload.old_master_key_authentication_hash)
+        .await?;
+
+    if !verification.is_valid() {
+        return Err(AppError::Unauthorized("Invalid password".to_string()));
+    }
+
+    // Validate that email and kdf settings match
+    let unlock_data = &payload.account_unlock_data.master_password_unlock_data;
+    if user.email != unlock_data.email {
+        return Err(AppError::BadRequest(
+            "Email mismatch in rotation request".to_string(),
+        ));
+    }
+
+    let now = Utc::now().format("%Y-%m-%dT%H:%M:%S%.3fZ").to_string();
+
+    // Update all folders with new encrypted names (batch operation)
+    let mut folder_statements: Vec<D1PreparedStatement> =
+        Vec::with_capacity(payload.account_data.folders.len());
+    for folder in &payload.account_data.folders {
+        let stmt = query!(
+            &db,
+            "UPDATE folders SET name = ?1, updated_at = ?2 WHERE id = ?3 AND user_id = ?4",
+            folder.name,
+            now,
+            folder.id,
+            user_id
+        )
+        .map_err(|_| AppError::Database)?;
+        folder_statements.push(stmt);
+    }
+    db::execute_in_batches(&db, folder_statements, batch_size).await?;
+
+    // Update all ciphers with new encrypted data (batch operation)
+    // Only update personal ciphers (organization_id is None)
+    let mut cipher_statements: Vec<D1PreparedStatement> =
+        Vec::with_capacity(payload.account_data.ciphers.len());
+    for cipher in &payload.account_data.ciphers {
+        // Skip organization ciphers
+        if cipher.organization_id.is_some() {
+            continue;
+        }
+
+        let cipher_data = CipherData {
+            name: cipher.name.clone(),
+            notes: cipher.notes.clone(),
+            login: cipher.login.clone(),
+            card: cipher.card.clone(),
+            identity: cipher.identity.clone(),
+            secure_note: cipher.secure_note.clone(),
+            fields: cipher.fields.clone(),
+            password_history: cipher.password_history.clone(),
+            reprompt: cipher.reprompt,
+        };
+
+        let data = serde_json::to_string(&cipher_data).map_err(|_| AppError::Internal)?;
+
+        let stmt = query!(
+            &db,
+            "UPDATE ciphers SET data = ?1, folder_id = ?2, favorite = ?3, updated_at = ?4 WHERE id = ?5 AND user_id = ?6",
+            data,
+            cipher.folder_id,
+            cipher.favorite,
+            now,
+            cipher.id,
+            user_id
+        )
+        .map_err(|_| AppError::Database)?;
+        cipher_statements.push(stmt);
+    }
+    db::execute_in_batches(&db, cipher_statements, batch_size).await?;
+
+    // Generate new salt and hash the new password
+    let new_salt = generate_salt()?;
+    let new_hashed_password =
+        hash_password_for_storage(&unlock_data.master_key_authentication_hash, &new_salt).await?;
+
+    // Generate new security stamp
+    let new_security_stamp = Uuid::new_v4().to_string();
+
+    // Update user record with new keys and password
+    query!(
+        &db,
+        "UPDATE users SET master_password_hash = ?1, password_salt = ?2, key = ?3, private_key = ?4, security_stamp = ?5, updated_at = ?6 WHERE id = ?7",
+        new_hashed_password,
+        new_salt,
+        unlock_data.master_key_encrypted_user_key,
+        payload.account_keys.user_key_encrypted_account_private_key,
+        new_security_stamp,
+        now,
+        user_id
+    )
+    .map_err(|_| AppError::Database)?
+    .run()
+    .await?;
+
+    Ok(Json(json!({})))
+}
diff --git a/src/handlers/identity.rs b/src/handlers/identity.rs
index 62bab19..151d463 100644
--- a/src/handlers/identity.rs
+++ b/src/handlers/identity.rs
@@ -1,6 +1,5 @@
 use axum::{extract::State, Form, Json};
 use chrono::{Duration, Utc};
-use constant_time_eq::constant_time_eq;
 use jsonwebtoken::{decode, encode, DecodingKey, EncodingKey, Header, Validation};
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
@@ -9,7 +8,7 @@ use worker::{query, Env};
 
 use crate::{
     auth::Claims,
-    crypto::{generate_salt, hash_password_for_storage, verify_password},
+    crypto::{generate_salt, hash_password_for_storage},
     db,
     error::AppError,
     models::user::User,
@@ -139,27 +138,16 @@ pub async fn token(
                 .await
                 .map_err(|_| AppError::Unauthorized("Invalid credentials".to_string()))?
                 .ok_or_else(|| AppError::Unauthorized("Invalid credentials".to_string()))?;
-            let user: User =
-                serde_json::from_value(user_value).map_err(|_| AppError::Internal)?;
+            let user: User = serde_json::from_value(user_value).map_err(|_| AppError::Internal)?;
 
-            // Check if user needs migration (no salt = legacy user)
-            let is_valid = if let Some(ref salt) = user.password_salt {
-                // New user with PBKDF2 hashed password
-                verify_password(&password_hash, &user.master_password_hash, salt).await?
-            } else {
-                // Legacy user: direct comparison
-                constant_time_eq(
-                    user.master_password_hash.as_bytes(),
-                    password_hash.as_bytes(),
-                )
-            };
+            let verification = user.verify_master_password(&password_hash).await?;
 
-            if !is_valid {
+            if !verification.is_valid() {
                 return Err(AppError::Unauthorized("Invalid credentials".to_string()));
             }
 
             // Migrate legacy user to PBKDF2 if password matches and no salt exists
-            let user = if user.password_salt.is_none() {
+            let user = if verification.needs_migration() {
                 // Generate new salt and hash the password
                 let new_salt = generate_salt()?;
                 let new_hash = hash_password_for_storage(&password_hash, &new_salt).await?;
@@ -219,4 +207,4 @@ pub async fn token(
         }
         _ => Err(AppError::BadRequest("Unsupported grant_type".to_string())),
     }
-}
\ No newline at end of file
+}
diff --git a/src/models/user.rs b/src/models/user.rs
index 384527c..ed102cd 100644
--- a/src/models/user.rs
+++ b/src/models/user.rs
@@ -1,5 +1,8 @@
+use constant_time_eq::constant_time_eq;
 use serde::{Deserialize, Serialize};
 
+use crate::{crypto::verify_password, error::AppError};
+
 #[derive(Debug, Serialize, Deserialize)]
 pub struct User {
     pub id: String,
@@ -20,6 +23,53 @@ pub struct User {
     pub updated_at: String,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum PasswordVerification {
+    MatchCurrentScheme,
+    MatchLegacyScheme,
+    Mismatch,
+}
+
+impl PasswordVerification {
+    pub fn is_valid(&self) -> bool {
+        matches!(
+            self,
+            PasswordVerification::MatchCurrentScheme | PasswordVerification::MatchLegacyScheme
+        )
+    }
+
+    pub fn needs_migration(&self) -> bool {
+        matches!(self, PasswordVerification::MatchLegacyScheme)
+    }
+}
+
+impl User {
+    pub async fn verify_master_password(
+        &self,
+        provided_hash: &str,
+    ) -> Result<PasswordVerification, AppError> {
+        if let Some(ref salt) = self.password_salt {
+            let is_valid = verify_password(provided_hash, &self.master_password_hash, salt).await?;
+            Ok(if is_valid {
+                PasswordVerification::MatchCurrentScheme
+            } else {
+                PasswordVerification::Mismatch
+            })
+        } else {
+            let is_valid = constant_time_eq(
+                self.master_password_hash.as_bytes(),
+                provided_hash.as_bytes(),
+            );
+
+            Ok(if is_valid {
+                PasswordVerification::MatchLegacyScheme
+            } else {
+                PasswordVerification::Mismatch
+            })
+        }
+    }
+}
+
 mod bool_from_int {
     use serde::{self, Deserialize, Deserializer, Serializer};
 
@@ -83,4 +133,96 @@ pub struct DeleteAccountRequest {
     #[serde(alias = "MasterPasswordHash")]
     pub master_password_hash: Option<String>,
     pub otp: Option<String>,
-}
\ No newline at end of file
+}
+
+// For POST /accounts/password request
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ChangePasswordRequest {
+    pub master_password_hash: String,
+    pub new_master_password_hash: String,
+    pub master_password_hint: Option<String>,
+    pub key: String,
+}
+
+// For POST /accounts/key-management/rotate-user-account-keys request
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct RotateKeyRequest {
+    pub account_unlock_data: RotateAccountUnlockData,
+    pub account_keys: RotateAccountKeys,
+    pub account_data: RotateAccountData,
+    pub old_master_key_authentication_hash: String,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct RotateAccountUnlockData {
+    pub master_password_unlock_data: MasterPasswordUnlockData,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct MasterPasswordUnlockData {
+    pub kdf_type: i32,
+    pub kdf_iterations: i32,
+    pub kdf_parallelism: Option<i32>,
+    pub kdf_memory: Option<i32>,
+    pub email: String,
+    pub master_key_authentication_hash: String,
+    pub master_key_encrypted_user_key: String,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct RotateAccountKeys {
+    pub user_key_encrypted_account_private_key: String,
+    pub account_public_key: String,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct RotateAccountData {
+    pub ciphers: Vec<RotateCipherData>,
+    pub folders: Vec<RotateFolderData>,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct RotateCipherData {
+    pub id: String,
+    #[serde(rename = "type")]
+    pub r#type: i32,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub folder_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub organization_id: Option<String>,
+    pub name: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub notes: Option<String>,
+    #[serde(default)]
+    pub favorite: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub login: Option<serde_json::Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub card: Option<serde_json::Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub identity: Option<serde_json::Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub secure_note: Option<serde_json::Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub fields: Option<serde_json::Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub password_history: Option<serde_json::Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub reprompt: Option<i32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub key: Option<String>,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct RotateFolderData {
+    pub id: String,
+    pub name: String,
+}
diff --git a/src/router.rs b/src/router.rs
index d490735..96aafde 100644
--- a/src/router.rs
+++ b/src/router.rs
@@ -29,6 +29,13 @@ pub fn api_router(env: Env) -> Router {
         // Delete account
         .route("/api/accounts", delete(accounts::delete_account))
         .route("/api/accounts/delete", post(accounts::delete_account))
+        // Change password
+        .route("/api/accounts/password", post(accounts::post_password))
+        // Rotate encryption keys
+        .route(
+            "/api/accounts/key-management/rotate-user-account-keys",
+            post(accounts::post_rotatekey),
+        )
         // Ciphers CRUD
         .route("/api/ciphers", post(ciphers::create_cipher_simple))
         .route("/api/ciphers/create", post(ciphers::create_cipher))
@@ -38,11 +45,20 @@ pub fn api_router(env: Env) -> Router {
         .route("/api/ciphers/{id}/delete", put(ciphers::soft_delete_cipher))
         // Cipher hard delete (DELETE/POST permanently removes cipher)
         .route("/api/ciphers/{id}", delete(ciphers::hard_delete_cipher))
-        .route("/api/ciphers/{id}/delete", post(ciphers::hard_delete_cipher))
+        .route(
+            "/api/ciphers/{id}/delete",
+            post(ciphers::hard_delete_cipher),
+        )
         // Cipher bulk soft delete
-        .route("/api/ciphers/delete", put(ciphers::soft_delete_ciphers_bulk))
+        .route(
+            "/api/ciphers/delete",
+            put(ciphers::soft_delete_ciphers_bulk),
+        )
         // Cipher bulk hard delete
-        .route("/api/ciphers/delete", post(ciphers::hard_delete_ciphers_bulk))
+        .route(
+            "/api/ciphers/delete",
+            post(ciphers::hard_delete_ciphers_bulk),
+        )
         .route("/api/ciphers", delete(ciphers::hard_delete_ciphers_bulk))
         // Cipher restore (clears deleted_at)
         .route("/api/ciphers/{id}/restore", put(ciphers::restore_cipher))