diff --git a/frontends/nextjs/src/lib/security/secure-db/execute-query.ts b/frontends/nextjs/src/lib/security/secure-db/execute-query.ts
new file mode 100644
index 000000000..aeea3501e
--- /dev/null
+++ b/frontends/nextjs/src/lib/security/secure-db/execute-query.ts
@@ -0,0 +1,40 @@
+import type { SecurityContext, OperationType, ResourceType } from './types'
+import { checkRateLimit } from './check-rate-limit'
+import { checkAccess } from './check-access'
+import { logOperation } from './log-operation'
+
+/**
+ * Execute a secure database query with rate limiting, access control, and audit logging
+ */
+export async function executeQuery<T>(
+  ctx: SecurityContext,
+  resource: ResourceType,
+  operation: OperationType,
+  queryFn: () => Promise<T>,
+  resourceId: string = 'unknown'
+): Promise<T> {
+  // Check rate limit
+  const canProceed = checkRateLimit(ctx.user.id)
+  if (!canProceed) {
+    await logOperation(ctx, operation, resource, resourceId, false, 'Rate limit exceeded')
+    throw new Error('Rate limit exceeded. Please try again later.')
+  }
+
+  // Check access permissions
+  const hasAccess = await checkAccess(ctx, resource, operation, resourceId)
+  if (!hasAccess) {
+    await logOperation(ctx, operation, resource, resourceId, false, 'Access denied')
+    throw new Error('Access denied. Insufficient permissions.')
+  }
+
+  // Execute query
+  try {
+    const result = await queryFn()
+    await logOperation(ctx, operation, resource, resourceId, true)
+    return result
+  } catch (error) {
+    const errorMessage = error instanceof Error ? error.message : 'Unknown error'
+    await logOperation(ctx, operation, resource, resourceId, false, errorMessage)
+    throw error
+  }
+}
diff --git a/frontends/nextjs/src/lib/security/secure-db/index.ts b/frontends/nextjs/src/lib/security/secure-db/index.ts
new file mode 100644
index 000000000..2b9600d6f
--- /dev/null
+++ b/frontends/nextjs/src/lib/security/secure-db/index.ts
@@ -0,0 +1,61 @@
+// Types
+export type { 
+  OperationType, 
+  ResourceType, 
+  AuditLog, 
+  SecurityContext, 
+  AccessRule 
+} from './types'
+
+// Core functions
+export { ACCESS_RULES } from './access-rules'
+export { checkAccess } from './check-access'
+export { checkRateLimit, clearRateLimit, clearAllRateLimits } from './check-rate-limit'
+export { sanitizeInput } from './sanitize-input'
+export { logOperation } from './log-operation'
+export { executeQuery } from './execute-query'
+
+// Operations
+export { getUsers } from './operations/get-users'
+export { getUserById } from './operations/get-user-by-id'
+export { createUser } from './operations/create-user'
+export { updateUser } from './operations/update-user'
+export { deleteUser } from './operations/delete-user'
+export { verifyCredentials } from './operations/verify-credentials'
+
+// Import all for namespace class
+import { ACCESS_RULES } from './access-rules'
+import { checkAccess } from './check-access'
+import { checkRateLimit, clearRateLimit, clearAllRateLimits } from './check-rate-limit'
+import { sanitizeInput } from './sanitize-input'
+import { logOperation } from './log-operation'
+import { executeQuery } from './execute-query'
+import { getUsers } from './operations/get-users'
+import { getUserById } from './operations/get-user-by-id'
+import { createUser } from './operations/create-user'
+import { updateUser } from './operations/update-user'
+import { deleteUser } from './operations/delete-user'
+import { verifyCredentials } from './operations/verify-credentials'
+
+/**
+ * SecureDatabase namespace class - groups all secure DB operations as static methods
+ */
+export class SecureDatabase {
+  // Core
+  static ACCESS_RULES = ACCESS_RULES
+  static checkAccess = checkAccess
+  static checkRateLimit = checkRateLimit
+  static clearRateLimit = clearRateLimit
+  static clearAllRateLimits = clearAllRateLimits
+  static sanitizeInput = sanitizeInput
+  static logOperation = logOperation
+  static executeQuery = executeQuery
+  
+  // Operations
+  static getUsers = getUsers
+  static getUserById = getUserById
+  static createUser = createUser
+  static updateUser = updateUser
+  static deleteUser = deleteUser
+  static verifyCredentials = verifyCredentials
+}
diff --git a/frontends/nextjs/src/lib/security/secure-db/log-operation.ts b/frontends/nextjs/src/lib/security/secure-db/log-operation.ts
new file mode 100644
index 000000000..4189f1535
--- /dev/null
+++ b/frontends/nextjs/src/lib/security/secure-db/log-operation.ts
@@ -0,0 +1,38 @@
+import type { SecurityContext, OperationType, ResourceType, AuditLog } from './types'
+
+/**
+ * Log an operation for audit trail
+ */
+export async function logOperation(
+  ctx: SecurityContext,
+  operation: OperationType,
+  resource: ResourceType,
+  resourceId: string,
+  success: boolean,
+  errorMessage?: string
+): Promise<void> {
+  const log: AuditLog = {
+    id: `audit_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`,
+    timestamp: Date.now(),
+    userId: ctx.user.id,
+    username: ctx.user.username,
+    operation,
+    resource,
+    resourceId,
+    success,
+    errorMessage,
+    ipAddress: ctx.ipAddress,
+  }
+  
+  try {
+    // TODO: Replace with proper audit log storage
+    // For now, just log to console in development
+    if (process.env.NODE_ENV === 'development') {
+      console.log('[AUDIT]', log)
+    }
+    // In production, this would write to a persistent audit log table
+    // await Database.addAuditLog(log)
+  } catch (error) {
+    console.error('Failed to log operation:', error)
+  }
+}
diff --git a/frontends/nextjs/src/lib/security/secure-db/operations/create-user.ts b/frontends/nextjs/src/lib/security/secure-db/operations/create-user.ts
new file mode 100644
index 000000000..f7a971a7f
--- /dev/null
+++ b/frontends/nextjs/src/lib/security/secure-db/operations/create-user.ts
@@ -0,0 +1,48 @@
+import { prisma } from '../../db/prisma'
+import type { User } from '../../types/level-types'
+import type { SecurityContext } from './types'
+import { executeQuery } from './execute-query'
+import { sanitizeInput } from './sanitize-input'
+
+/**
+ * Create a new user with security checks
+ */
+export async function createUser(
+  ctx: SecurityContext, 
+  userData: Omit<User, 'id' | 'createdAt'>
+): Promise<User> {
+  const sanitized = sanitizeInput(userData)
+  
+  return executeQuery(
+    ctx,
+    'user',
+    'CREATE',
+    async () => {
+      const user = await prisma.user.create({
+        data: {
+          id: `user_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`,
+          username: sanitized.username,
+          email: sanitized.email,
+          role: sanitized.role,
+          profilePicture: sanitized.profilePicture,
+          bio: sanitized.bio,
+          createdAt: BigInt(Date.now()),
+          tenantId: sanitized.tenantId,
+          isInstanceOwner: sanitized.isInstanceOwner || false,
+        },
+      })
+      return {
+        id: user.id,
+        username: user.username,
+        email: user.email,
+        role: user.role as User['role'],
+        profilePicture: user.profilePicture || undefined,
+        bio: user.bio || undefined,
+        createdAt: Number(user.createdAt),
+        tenantId: user.tenantId || undefined,
+        isInstanceOwner: user.isInstanceOwner,
+      }
+    },
+    'new_user'
+  )
+}
diff --git a/frontends/nextjs/src/lib/security/secure-db/operations/delete-user.ts b/frontends/nextjs/src/lib/security/secure-db/operations/delete-user.ts
new file mode 100644
index 000000000..fa3ee2899
--- /dev/null
+++ b/frontends/nextjs/src/lib/security/secure-db/operations/delete-user.ts
@@ -0,0 +1,18 @@
+import { prisma } from '../../db/prisma'
+import type { SecurityContext } from './types'
+import { executeQuery } from './execute-query'
+
+/**
+ * Delete a user with security checks
+ */
+export async function deleteUser(ctx: SecurityContext, userId: string): Promise<void> {
+  return executeQuery(
+    ctx,
+    'user',
+    'DELETE',
+    async () => {
+      await prisma.user.delete({ where: { id: userId } })
+    },
+    userId
+  )
+}
diff --git a/frontends/nextjs/src/lib/security/secure-db/operations/get-user-by-id.ts b/frontends/nextjs/src/lib/security/secure-db/operations/get-user-by-id.ts
new file mode 100644
index 000000000..2e84eb934
--- /dev/null
+++ b/frontends/nextjs/src/lib/security/secure-db/operations/get-user-by-id.ts
@@ -0,0 +1,31 @@
+import { prisma } from '../../db/prisma'
+import type { User } from '../../types/level-types'
+import type { SecurityContext } from './types'
+import { executeQuery } from './execute-query'
+
+/**
+ * Get a user by ID with security checks
+ */
+export async function getUserById(ctx: SecurityContext, userId: string): Promise<User | null> {
+  return executeQuery(
+    ctx,
+    'user',
+    'READ',
+    async () => {
+      const user = await prisma.user.findUnique({ where: { id: userId } })
+      if (!user) return null
+      return {
+        id: user.id,
+        username: user.username,
+        email: user.email,
+        role: user.role as User['role'],
+        profilePicture: user.profilePicture || undefined,
+        bio: user.bio || undefined,
+        createdAt: Number(user.createdAt),
+        tenantId: user.tenantId || undefined,
+        isInstanceOwner: user.isInstanceOwner,
+      }
+    },
+    userId
+  )
+}
diff --git a/frontends/nextjs/src/lib/security/secure-db/operations/get-users.ts b/frontends/nextjs/src/lib/security/secure-db/operations/get-users.ts
new file mode 100644
index 000000000..2fd1368b1
--- /dev/null
+++ b/frontends/nextjs/src/lib/security/secure-db/operations/get-users.ts
@@ -0,0 +1,30 @@
+import { prisma } from '../../db/prisma'
+import type { User } from '../../types/level-types'
+import type { SecurityContext } from './types'
+import { executeQuery } from './execute-query'
+
+/**
+ * Get all users with security checks
+ */
+export async function getUsers(ctx: SecurityContext): Promise<User[]> {
+  return executeQuery(
+    ctx,
+    'user',
+    'READ',
+    async () => {
+      const users = await prisma.user.findMany()
+      return users.map(u => ({
+        id: u.id,
+        username: u.username,
+        email: u.email,
+        role: u.role as User['role'],
+        profilePicture: u.profilePicture || undefined,
+        bio: u.bio || undefined,
+        createdAt: Number(u.createdAt),
+        tenantId: u.tenantId || undefined,
+        isInstanceOwner: u.isInstanceOwner,
+      }))
+    },
+    'all_users'
+  )
+}
diff --git a/frontends/nextjs/src/lib/security/secure-db/operations/update-user.ts b/frontends/nextjs/src/lib/security/secure-db/operations/update-user.ts
new file mode 100644
index 000000000..49dfbd952
--- /dev/null
+++ b/frontends/nextjs/src/lib/security/secure-db/operations/update-user.ts
@@ -0,0 +1,47 @@
+import { prisma } from '../../db/prisma'
+import type { User } from '../../types/level-types'
+import type { SecurityContext } from './types'
+import { executeQuery } from './execute-query'
+import { sanitizeInput } from './sanitize-input'
+
+/**
+ * Update a user with security checks
+ */
+export async function updateUser(
+  ctx: SecurityContext, 
+  userId: string, 
+  updates: Partial<User>
+): Promise<User> {
+  const sanitized = sanitizeInput(updates)
+  
+  return executeQuery(
+    ctx,
+    'user',
+    'UPDATE',
+    async () => {
+      const user = await prisma.user.update({
+        where: { id: userId },
+        data: {
+          username: sanitized.username,
+          email: sanitized.email,
+          role: sanitized.role,
+          profilePicture: sanitized.profilePicture,
+          bio: sanitized.bio,
+          tenantId: sanitized.tenantId,
+        },
+      })
+      return {
+        id: user.id,
+        username: user.username,
+        email: user.email,
+        role: user.role as User['role'],
+        profilePicture: user.profilePicture || undefined,
+        bio: user.bio || undefined,
+        createdAt: Number(user.createdAt),
+        tenantId: user.tenantId || undefined,
+        isInstanceOwner: user.isInstanceOwner,
+      }
+    },
+    userId
+  )
+}
diff --git a/frontends/nextjs/src/lib/security/secure-db/operations/verify-credentials.ts b/frontends/nextjs/src/lib/security/secure-db/operations/verify-credentials.ts
new file mode 100644
index 000000000..275d8e96b
--- /dev/null
+++ b/frontends/nextjs/src/lib/security/secure-db/operations/verify-credentials.ts
@@ -0,0 +1,37 @@
+import { prisma } from '../../db/prisma'
+import type { SecurityContext } from './types'
+import { executeQuery } from './execute-query'
+import { sanitizeInput } from './sanitize-input'
+
+/**
+ * Verify user credentials with security checks
+ */
+export async function verifyCredentials(
+  ctx: SecurityContext, 
+  username: string, 
+  password: string
+): Promise<boolean> {
+  const sanitizedUsername = sanitizeInput(username)
+  
+  return executeQuery(
+    ctx,
+    'credential',
+    'READ',
+    async () => {
+      const credential = await prisma.credential.findUnique({
+        where: { username: sanitizedUsername },
+      })
+      
+      if (!credential) return false
+      
+      const encoder = new TextEncoder()
+      const data = encoder.encode(password)
+      const hashBuffer = await crypto.subtle.digest('SHA-512', data)
+      const hashArray = Array.from(new Uint8Array(hashBuffer))
+      const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('')
+      
+      return hashHex === credential.passwordHash
+    },
+    sanitizedUsername
+  )
+}