Session 6.3 – Security & Protection

CIA Triad Components:

┌─ CONFIDENTIALITY ─────────────────────────────────────────┐
│ Definition: Information is accessible only to authorized entities │
│                                                           │
│ Implementation Mechanisms:                                │
│   • Encryption (symmetric & asymmetric)                   │
│   • Access control lists (ACLs)                           │
│   • Authentication and authorization                       │
│   • Data classification and labeling                       │
│                                                           │
│ Threats: Eavesdropping, unauthorized access, data theft │
└───────────────────────────────────────────────────────────┘

┌─ INTEGRITY ───────────────────────────────────────────────┐
│ Definition: Information is accurate and unaltered          │
│                                                           │
│ Implementation Mechanisms:                                │
│   • Cryptographic hashes (SHA-256, SHA-3)                │
│   • Digital signatures and certificates                   │
│   • Version control and audit trails                      │
│   • Input validation and sanitization                     │
│                                                           │
│ Threats: Data tampering, unauthorized modification       │
└───────────────────────────────────────────────────────────┘

┌─ AVAILABILITY ────────────────────────────────────────────┐
│ Definition: Information is accessible when needed          │
│                                                           │
│ Implementation Mechanisms:                                │
│   • Redundancy and fault tolerance                        │
│   • Load balancing and clustering                         │
│   • Backup and disaster recovery                          │
│   • DDoS protection and rate limiting                     │
│                                                           │
│ Threats: DoS attacks, hardware failures, power outages   │
└───────────────────────────────────────────────────────────┘

Extended Security Models:

AAA Model (Authentication, Authorization, Accounting):
  ┌─────────────────┬─────────────────┬─────────────────┐
  │ AUTHENTICATION  │  AUTHORIZATION  │   ACCOUNTING    │
  ├─────────────────┼─────────────────┼─────────────────┤
  │ Who are you?    │ What can you do?│ What did you do?│
  │                 │                 │                 │
  │ • Passwords     │ • Permissions   │ • Audit logs    │
  │ • Biometrics    │ • Roles         │ • Access logs   │
  │ • Certificates  │ • Policies      │ • Billing info  │
  │ • Multi-factor  │ • Capabilities  │ • Usage stats   │
  └─────────────────┴─────────────────┴─────────────────┘

Bell-LaPadula Model - Confidentiality Focused:

Security Levels (Hierarchical):
  ┌─────────────────────────────────────────────────────┐
  │ TOP SECRET    (Level 4) - Highest Classification    │
  │ SECRET        (Level 3) - Restricted Information    │
  │ CONFIDENTIAL  (Level 2) - Limited Access Required   │
  │ UNCLASSIFIED  (Level 1) - Public Information       │
  └─────────────────────────────────────────────────────┘

Algorithm Bell_LaPadula_Access_Control:
Input: subject_clearance, object_classification, access_type
Output: ALLOW/DENY decision

BEGIN
    // Simple Security Property (No Read Up)
    IF access_type == READ THEN
        IF subject_clearance >= object_classification THEN
            read_permission = ALLOW
        ELSE
            read_permission = DENY
        END IF
    END IF
    
    // *-Property (No Write Down)
    IF access_type == WRITE THEN
        IF subject_clearance <= object_classification THEN
            write_permission = ALLOW
        ELSE
            write_permission = DENY
        END IF
    END IF
    
    RETURN permission_decision
END

Security Properties:
┌──────────────────────────────────────────────────────────────┐
│ Simple Security Property: "No Read Up"                    │
│   • Subjects cannot read objects at higher security levels   │
│   • Prevents unauthorized information disclosure             │
│                                                              │
│ *-Property: "No Write Down"                              │
│   • Subjects cannot write to objects at lower levels        │
│   • Prevents classified information from being downgraded   │
│                                                              │
│ Discretionary Security Property:                          │
│   • Access control matrix must be respected                 │
│   • Additional restrictions beyond mandatory controls       │
└──────────────────────────────────────────────────────────────┘

Example Access Scenarios:
Subject: Alice (SECRET clearance)
┌─────────────────┬─────────────┬──────────────┬────────────┐
│    Operation    │   Object    │ Classification│   Result   │
├─────────────────┼─────────────┼──────────────┼────────────┤
│ READ            │ File1.txt   │ CONFIDENTIAL │ ✓ ALLOW    │
│ READ            │ File2.doc   │ TOP SECRET   │ ✗ DENY     │
│ WRITE           │ File3.log   │ CONFIDENTIAL │ ✗ DENY     │
│ WRITE           │ File4.dat   │ SECRET       │ ✓ ALLOW    │
└─────────────────┴─────────────┴──────────────┴────────────┘

Biba Model - Dual to Bell-LaPadula (Integrity Focus):

Integrity Levels (Hierarchical):
  ┌─────────────────────────────────────────────────────┐
  │ CRITICAL     (Level 4) - Highest Integrity          │
  │ IMPORTANT    (Level 3) - High Integrity Required    │
  │ ROUTINE      (Level 2) - Standard Integrity         │
  │ UNVERIFIED   (Level 1) - Lowest/Unknown Integrity   │
  └─────────────────────────────────────────────────────┘

Algorithm Biba_Integrity_Control:
Input: subject_integrity_level, object_integrity_level, access_type
Output: ALLOW/DENY decision

BEGIN
    // Simple Integrity Property (No Read Down)
    IF access_type == READ THEN
        IF subject_integrity >= object_integrity THEN
            read_permission = ALLOW
        ELSE
            read_permission = DENY  // Prevent contamination
        END IF
    END IF
    
    // *-Integrity Property (No Write Up)
    IF access_type == WRITE THEN
        IF subject_integrity >= object_integrity THEN
            write_permission = ALLOW
        ELSE
            write_permission = DENY  // Prevent corruption
        END IF
    END IF
    
    RETURN permission_decision
END

Bell-LaPadula vs Biba Comparison:
┌─────────────────────┬─────────────────┬─────────────────┐
│      Property       │  Bell-LaPadula  │      Biba       │
├─────────────────────┼─────────────────┼─────────────────┤
│ Primary Concern     │ Confidentiality │ Integrity       │
│ Read Rule           │ No Read Up      │ No Read Down    │
│ Write Rule          │ No Write Down   │ No Write Up     │
│ Information Flow    │ Upward Only     │ Downward Only   │
│ Trust Direction     │ Higher = Trusted│ Lower = Trusted │
└─────────────────────┴─────────────────┴─────────────────┘

DAC Implementation Algorithm:

Data Structures:
    access_control_matrix[subject][object] = permissions[]
    object_owner[object] = owner_subject
    user_groups[subject] = group_list[]

Algorithm DAC_Access_Check:
Input: subject, object, requested_permission
Output: ALLOW/DENY decision

BEGIN
    // Owner has full control
    IF subject == object_owner[object] THEN
        RETURN ALLOW
    END IF
    
    // Check direct permissions
    IF requested_permission IN access_control_matrix[subject][object] THEN
        RETURN ALLOW
    END IF
    
    // Check group permissions
    FOR EACH group IN user_groups[subject] DO
        IF requested_permission IN access_control_matrix[group][object] THEN
            RETURN ALLOW
        END IF
    END FOR
    
    // Check default permissions
    IF requested_permission IN access_control_matrix[ALL_USERS][object] THEN
        RETURN ALLOW
    END IF
    
    RETURN DENY
END

UNIX File Permissions Example:
┌──────────────────────────────────────────────────────────────┐
│ File: /home/alice/document.txt                               │
│ Permissions: -rw-r--r-- (644 in octal)                      │
│                                                              │
│ Breakdown:                                                   │
│   - : Regular file                                           │
│   rw- : Owner (alice) can read and write                    │
│   r-- : Group can read only                                 │
│   r-- : Others can read only                                │
│                                                              │
│ Permission Bits:                                             │
│   r (read)    = 4                                           │
│   w (write)   = 2                                           │
│   x (execute) = 1                                           │
└──────────────────────────────────────────────────────────────┘

Access Control List (ACL) Structure:
ACL for /secure/database.db:
┌─────────────────────────────────────────────────────────────┐
│ user:alice:rw-     # Alice can read and write              │
│ user:bob:r--       # Bob can only read                     │
│ group:dba:rwx      # Database admins have full access     │
│ group:users:r--    # Regular users can read               │
│ other::---         # No access for others                 │
│ mask::rw-          # Maximum effective permissions        │
└─────────────────────────────────────────────────────────────┘

MAC Implementation Algorithm:

Data Structures:
    security_labels[subject] = classification_level
    security_labels[object] = classification_level
    compartments[subject] = compartment_set[]
    compartments[object] = compartment_set[]

Algorithm MAC_Access_Check:
Input: subject, object, access_mode
Output: ALLOW/DENY decision

BEGIN
    subject_level = security_labels[subject]
    object_level = security_labels[object]
    subject_compartments = compartments[subject]
    object_compartments = compartments[object]
    
    IF access_mode == READ THEN
        // Subject must dominate object (can read down)
        IF subject_level >= object_level AND 
           object_compartments ⊆ subject_compartments THEN
            RETURN ALLOW
        ELSE
            RETURN DENY
        END IF
    END IF
    
    IF access_mode == write THEN
        // Object must dominate subject (can write up)
        IF object_level >= subject_level AND 
           subject_compartments ⊆ object_compartments THEN
            RETURN ALLOW
        ELSE
            RETURN DENY
        END IF
    END IF
END

SELinux MAC Example:
┌─────────────────────────────────────────────────────────────┐
│ Security Context Format: user:role:type:level               │
│                                                             │
│ Process: alice:user_r:user_t:s0-s15:c0.c1023              │
│   • User: alice                                            │
│   • Role: user_r (user role)                              │
│   • Type: user_t (user process type)                      │
│   • Level: s0-s15 (sensitivity levels 0-15)               │
│   • Categories: c0.c1023 (categories 0-1023)              │
│                                                             │
│ File: system_u:object_r:admin_home_t:s15:c100.c200        │
│   • High security level (s15)                             │
│   • Limited categories (c100-c200)                        │
│   • Admin home type                                        │
└─────────────────────────────────────────────────────────────┘

Type Enforcement Rules:
allow user_t user_home_t:file { read write create };
allow admin_t admin_home_t:file { read write create delete };
deny user_t admin_home_t:file *;  # Users cannot access admin files

RBAC Model Implementation:

Data Structures:
    user_roles[user] = role_set[]
    role_permissions[role] = permission_set[]
    role_hierarchy[role] = parent_roles[]
    session_roles[session] = active_roles[]

Algorithm RBAC_Access_Check:
Input: user, object, operation, session
Output: ALLOW/DENY decision

BEGIN
    required_permission = create_permission(object, operation)
    active_roles = session_roles[session]
    
    FOR EACH role IN active_roles DO
        // Check direct role permissions
        IF required_permission IN role_permissions[role] THEN
            RETURN ALLOW
        END IF
        
        // Check inherited permissions from role hierarchy
        inherited_permissions = get_inherited_permissions(role)
        IF required_permission IN inherited_permissions THEN
            RETURN ALLOW
        END IF
    END FOR
    
    RETURN DENY
END

Algorithm Activate_Role:
Input: user, role, session
Output: SUCCESS/FAILURE

BEGIN
    // Check if user is assigned to role
    IF role NOT IN user_roles[user] THEN
        RETURN FAILURE
    END IF
    
    // Check cardinality constraints
    IF |session_roles[session]| >= max_roles_per_session THEN
        RETURN FAILURE
    END IF
    
    // Check separation of duty constraints
    FOR EACH active_role IN session_roles[session] DO
        IF conflicts(role, active_role) THEN
            RETURN FAILURE
        END IF
    END FOR
    
    session_roles[session].add(role)
    RETURN SUCCESS
END

RBAC Example - Hospital System:
┌─────────────────────────────────────────────────────────────┐
│ Users:           Roles:            Permissions:             │
│                                                             │
│ Dr. Smith  ──→   Doctor      ──→   read_patient_record     │
│ Nurse Jane ──→   Nurse       ──→   write_patient_notes     │
│ Admin Bob  ──→   HR_Manager  ──→   manage_staff_schedules  │
│            ──→   IT_Admin    ──→   system_administration   │
│                                                             │
│ Role Hierarchy:                                             │
│   Senior_Doctor ──→ Doctor ──→ Medical_Staff               │
│   Head_Nurse ──→ Nurse ──→ Medical_Staff                  │
│   System_Admin ──→ IT_Admin                                │
│                                                             │
│ Constraints:                                                │
│   • Doctors and Auditors are mutually exclusive            │
│   • Maximum 3 active roles per session                     │
│   • IT_Admin cannot access patient records                 │
└─────────────────────────────────────────────────────────────┘

AES (Advanced Encryption Standard) Implementation:

Algorithm AES_Encrypt:
Input: plaintext, key, mode
Output: ciphertext

BEGIN
    // Key expansion
    round_keys = expand_key(key)  // Generate 11 round keys from 128-bit key
    
    // Initial round
    state = add_round_key(plaintext, round_keys[0])
    
    // Main rounds (9 rounds for AES-128)
    FOR round = 1 TO 9 DO
        state = substitute_bytes(state)    // S-box substitution
        state = shift_rows(state)          // Row shifting
        state = mix_columns(state)         // Column mixing
        state = add_round_key(state, round_keys[round])
    END FOR
    
    // Final round (no mix_columns)
    state = substitute_bytes(state)
    state = shift_rows(state)
    ciphertext = add_round_key(state, round_keys[10])
    
    RETURN ciphertext
END

Block Cipher Modes of Operation:

1. Electronic Codebook (ECB) - NOT RECOMMENDED
   C[i] = E(K, P[i])
   • Each block encrypted independently
   • Identical plaintext blocks → identical ciphertext blocks
   • Vulnerable to pattern analysis

2. Cipher Block Chaining (CBC) - SECURE
   C[0] = IV (Initialization Vector)
   C[i] = E(K, P[i] ⊕ C[i-1])
   • Each block depends on previous ciphertext
   • Same plaintext produces different ciphertext

3. Counter Mode (CTR) - SECURE & PARALLEL
   C[i] = P[i] ⊕ E(K, IV + i)
   • Converts block cipher to stream cipher
   • Parallelizable encryption/decryption
   • No error propagation

Performance Comparison:
┌─────────────┬──────────────┬───────────────┬─────────────────┐
│    Mode     │  Encryption  │  Decryption   │   Parallelism   │
├─────────────┼──────────────┼───────────────┼─────────────────┤
│ ECB         │ Parallel     │ Parallel      │ Full            │
│ CBC         │ Sequential   │ Parallel      │ Decrypt only    │
│ CTR         │ Parallel     │ Parallel      │ Full            │
│ GCM         │ Parallel     │ Parallel      │ Full + Auth     │
└─────────────┴──────────────┴───────────────┴─────────────────┘

RSA Algorithm Implementation:

Algorithm RSA_Key_Generation:
Output: public_key (n, e), private_key (n, d)

BEGIN
    // Step 1: Generate two large primes
    p = generate_large_prime(1024 bits)
    q = generate_large_prime(1024 bits)
    
    // Step 2: Compute n and φ(n)
    n = p × q                    // Modulus
    phi_n = (p - 1) × (q - 1)   // Euler's totient
    
    // Step 3: Choose public exponent
    e = 65537                    // Common choice: 2^16 + 1
    
    // Step 4: Compute private exponent
    d = modular_inverse(e, phi_n)  // ed ≡ 1 (mod φ(n))
    
    public_key = (n, e)
    private_key = (n, d)
    
    RETURN public_key, private_key
END

Algorithm RSA_Encrypt:
Input: message m, public_key (n, e)
Output: ciphertext c

BEGIN
    // Ensure message is smaller than modulus
    IF m >= n THEN
        RETURN ERROR
    END IF
    
    c = fast_modular_exponentiation(m, e, n)  // c = m^e mod n
    RETURN c
END

Algorithm RSA_Decrypt:
Input: ciphertext c, private_key (n, d)
Output: message m

BEGIN
    m = fast_modular_exponentiation(c, d, n)  // m = c^d mod n
    RETURN m
END

Digital Signature with RSA:
Algorithm RSA_Sign:
Input: message, private_key
Output: digital_signature

BEGIN
    hash_value = SHA256(message)
    signature = RSA_Decrypt(hash_value, private_key)  // Using private key
    RETURN signature
END

Algorithm RSA_Verify:
Input: message, signature, public_key
Output: VALID/INVALID

BEGIN
    hash_value = SHA256(message)
    decrypted_hash = RSA_Encrypt(signature, public_key)  // Using public key
    
    IF hash_value == decrypted_hash THEN
        RETURN VALID
    ELSE
        RETURN INVALID
    END IF
END

Elliptic Curve Cryptography (ECC) Advantages:
┌──────────────────────────────────────────────────────────────┐
│ Security Level Comparison:                                   │
│                                                              │
│ RSA Key Size    ECC Key Size    Security Bits               │
│ ─────────────   ─────────────   ──────────────               │
│ 1024 bits       160 bits        80 bits                     │
│ 2048 bits       224 bits        112 bits                    │
│ 3072 bits       256 bits        128 bits                    │
│ 7680 bits       384 bits        192 bits                    │
│ 15360 bits      512 bits        256 bits                    │
│                                                              │
│ ECC Benefits:                                                │
│ • Smaller key sizes for equivalent security                 │
│ • Faster computation                                         │
│ • Lower memory usage                                         │
│ • Reduced bandwidth requirements                             │
└──────────────────────────────────────────────────────────────┘

SHA-256 (Secure Hash Algorithm) Implementation:

Algorithm SHA256_Hash:
Input: message
Output: 256-bit hash digest

BEGIN
    // Initialize hash values (first 32 bits of fractional parts)
    h[0] = 0x6a09e667    h[1] = 0xbb67ae85    h[2] = 0x3c6ef372    h[3] = 0xa54ff53a
    h[4] = 0x510e527f    h[5] = 0x9b05688c    h[6] = 0x1f83d9ab    h[7] = 0x5be0cd19
    
    // Initialize round constants (first 32 bits of cube roots)
    k[0..63] = [0x428a2f98, 0x71374491, 0xb5c0fbcf, ...]
    
    // Pre-processing: padding message
    padded_message = message + '1' + zeros + length_in_bits
    
    // Process message in 512-bit chunks
    FOR EACH 512-bit chunk DO
        // Break chunk into sixteen 32-bit words
        w[0..15] = chunk_words
        
        // Extend to 64 words
        FOR i = 16 TO 63 DO
            s0 = right_rotate(w[i-15], 7) XOR right_rotate(w[i-15], 18) XOR (w[i-15] >> 3)
            s1 = right_rotate(w[i-2], 17) XOR right_rotate(w[i-2], 19) XOR (w[i-2] >> 10)
            w[i] = w[i-16] + s0 + w[i-7] + s1
        END FOR
        
        // Initialize working variables
        a, b, c, d, e, f, g, h = h[0], h[1], h[2], h[3], h[4], h[5], h[6], h[7]
        
        // Main compression loop
        FOR i = 0 TO 63 DO
            S1 = right_rotate(e, 6) XOR right_rotate(e, 11) XOR right_rotate(e, 25)
            ch = (e AND f) XOR ((NOT e) AND g)
            temp1 = h + S1 + ch + k[i] + w[i]
            S0 = right_rotate(a, 2) XOR right_rotate(a, 13) XOR right_rotate(a, 22)
            maj = (a AND b) XOR (a AND c) XOR (b AND c)
            temp2 = S0 + maj
            
            h = g
            g = f  
            f = e
            e = d + temp1
            d = c
            c = b
            b = a
            a = temp1 + temp2
        END FOR
        
        // Add compressed chunk to current hash value
        h[0] += a    h[1] += b    h[2] += c    h[3] += d
        h[4] += e    h[5] += f    h[6] += g    h[7] += h
    END FOR
    
    // Produce final hash value
    hash = concatenate(h[0], h[1], h[2], h[3], h[4], h[5], h[6], h[7])
    RETURN hash
END

Hash Function Properties:
┌─────────────────────────────────────────────────────────────┐
│ 1. Deterministic: Same input → Same output               │
│    hash("hello") = always the same 256-bit value           │
│                                                             │
│ 2. Fast Computation: Efficient to compute                │
│    Modern CPU: ~1 GB/s hashing speed                       │
│                                                             │
│ 3. Pre-image Resistance: One-way function                │
│    Given hash(x), computationally infeasible to find x     │
│                                                             │
│ 4. Collision Resistance: Hard to find duplicates          │
│    Infeasible to find x ≠ y such that hash(x) = hash(y)   │
│                                                             │
│ 5. Avalanche Effect: Small input change → Large output change │
│    hash("hello") vs hash("Hello") differ significantly     │
└─────────────────────────────────────────────────────────────┘

Common Hash Functions Comparison:
┌─────────────┬───────────┬─────────────┬─────────────────────┐
│  Algorithm  │ Hash Size │ Block Size  │ Security Status     │
├─────────────┼───────────┼─────────────┼─────────────────────┤
│ MD5         │ 128 bits  │ 512 bits    │ ✗ Broken           │
│ SHA-1       │ 160 bits  │ 512 bits    │ ⚠ Deprecated        │
│ SHA-256     │ 256 bits  │ 512 bits    │ ✓ Secure           │
│ SHA-3       │ Variable  │ Variable    │ ✓ Secure (Latest)  │
│ BLAKE2      │ Variable  │ Variable    │ ✓ Fast & Secure    │
└─────────────┴───────────┴─────────────┴─────────────────────┘

Buffer Overflow Attack:

Vulnerable Code Example:
```c
void vulnerable_function(char* input) {
    char buffer[100];           // Fixed-size buffer
    strcpy(buffer, input);      // No bounds checking!
    printf("Input: %s\n", buffer);
}
```

Attack Mechanism:
┌────────────────────────────────────────────────────────────┐
│ Normal Stack Frame:                                        │
│ ┌──────────────┬─────────────┬────────────────────────┐   │
│ │ Return Addr  │   Buffer    │    Other Variables     │   │
│ │   (4 bytes)  │  (100 bytes)│                        │   │
│ └──────────────┴─────────────┴────────────────────────┘   │
│                                                            │
│ After Buffer Overflow:                                     │
│ ┌──────────────┬─────────────┬────────────────────────┐   │
│ │ OVERWRITTEN  │ AAAAAAAAAA  │      AAAAAAAAAA       │   │
│ │ RETURN ADDR  │ AAAAAAAAAA  │      AAAAAAAAAA       │   │
│ └──────────────┴─────────────┴────────────────────────┘   │
│                                                            │
│ Result: Control flow hijacked to attacker's code          │
└────────────────────────────────────────────────────────────┘

Algorithm Buffer_Overflow_Prevention:
BEGIN
    // 1. Input Validation
    IF input_length > BUFFER_SIZE - 1 THEN
        truncate_input() OR reject_input()
    END IF
    
    // 2. Use Safe Functions
    strncpy(buffer, input, BUFFER_SIZE - 1)
    buffer[BUFFER_SIZE - 1] = '\0'  // Ensure null termination
    
    // 3. Stack Canaries (Compiler-generated)
    stack_canary = random_value()
    // Place canary between buffer and return address
    // Check canary before function return
    
    // 4. Address Space Layout Randomization (ASLR)
    randomize_memory_layout()  // OS-level protection
    
    // 5. Non-Executable Stack (NX bit)
    mark_stack_non_executable()  // Hardware-supported
END

SQL Injection Attack:

Vulnerable Query:
query = "SELECT * FROM users WHERE username='" + username + 
        "' AND password='" + password + "'"

Attack Input:
username = "admin"
password = "' OR '1'='1' --"

Resulting Query:
SELECT * FROM users WHERE username='admin' AND password='' OR '1'='1' --'
                                                          ↑
                                              Always true condition

Algorithm SQL_Injection_Prevention:
BEGIN
    // 1. Parameterized Queries (Best Practice)
    prepared_statement = "SELECT * FROM users WHERE username=? AND password=?"
    execute_query(prepared_statement, [username, password])
    
    // 2. Input Sanitization
    username = escape_sql_characters(username)
    password = escape_sql_characters(password)
    
    // 3. Stored Procedures
    call_stored_procedure("authenticate_user", username, password)
    
    // 4. Whitelist Validation
    IF NOT matches_pattern(username, "^[a-zA-Z0-9_]+$") THEN
        reject_input()
    END IF
END

Cross-Site Scripting (XSS) Attack:

Attack Vector:
User Input: <script>alert('XSS');</script>
Reflected in HTML: <div>Welcome <script>alert('XSS');</script>!</div>

Algorithm XSS_Prevention:
BEGIN
    // 1. Output Encoding
    user_input = html_encode(user_input)
    // < becomes <, > becomes >
    
    // 2. Content Security Policy (CSP)
    set_header("Content-Security-Policy", 
               "script-src 'self'; object-src 'none';")
    
    // 3. Input Validation
    IF contains_script_tags(user_input) THEN
        sanitize_input() OR reject_input()
    END IF
    
    // 4. HttpOnly Cookies
    set_cookie("session_id", value, {httpOnly: true, secure: true})
END

APT Attack Lifecycle:

Phase 1: Initial Compromise
┌─────────────────────────────────────────────────────────────┐
│ Attack Vectors:                                             │
│ • Spear phishing emails with malicious attachments         │
│ • Watering hole attacks on trusted websites                │
│ • Supply chain compromises                                  │
│ • Zero-day exploits                                         │
│                                                             │
│ Goals:                                                      │
│ • Establish initial foothold in target network             │
│ • Deploy persistent backdoors                              │
│ • Avoid detection by security systems                      │
└─────────────────────────────────────────────────────────────┘

Phase 2: Establish Foothold
┌─────────────────────────────────────────────────────────────┐
│ Techniques:                                                 │
│ • Install rootkits and stealthy malware                    │
│ • Create legitimate-looking services                        │
│ • Modify system files and registry entries                 │
│ • Establish command and control (C2) channels              │
│                                                             │
│ Persistence Mechanisms:                                     │
│ • Registry autostart locations                             │
│ • Scheduled tasks and services                             │
│ • DLL hijacking and process injection                      │
│ • Boot sector modifications                                 │
└─────────────────────────────────────────────────────────────┘

Phase 3: Escalate Privileges
┌─────────────────────────────────────────────────────────────┐
│ Techniques:                                                 │
│ • Exploit local vulnerabilities                            │
│ • Steal credentials from memory                            │
│ • Pass-the-hash attacks                                    │
│ • Token manipulation and impersonation                     │
│                                                             │
│ Tools:                                                      │
│ • Mimikatz for credential extraction                       │
│ • PowerShell Empire for post-exploitation                  │
│ • Cobalt Strike for adversary simulation                   │
└─────────────────────────────────────────────────────────────┘

Phase 4: Internal Reconnaissance
┌─────────────────────────────────────────────────────────────┐
│ Information Gathering:                                      │
│ • Network topology mapping                                 │
│ • Active Directory enumeration                             │
│ • File share discovery                                     │
│ • Database and system identification                       │
│                                                             │
│ Techniques:                                                 │
│ • LDAP queries for user and group information             │
│ • Network scanning from compromised hosts                  │
│ • Living off the land with built-in tools                 │
└─────────────────────────────────────────────────────────────┘

Phase 5: Lateral Movement
┌─────────────────────────────────────────────────────────────┐
│ Movement Techniques:                                        │
│ • Remote desktop protocol (RDP)                           │
│ • Windows Management Instrumentation (WMI)                 │
│ • PowerShell remoting                                      │
│ • SSH tunneling and port forwarding                       │
│                                                             │
│ Credential Attacks:                                         │
│ • Pass-the-hash                                           │
│ • Pass-the-ticket (Kerberos)                              │
│ • Golden ticket attacks                                    │
│ • Silver ticket attacks                                    │
└─────────────────────────────────────────────────────────────┘

Algorithm APT_Detection:
BEGIN
    // Behavioral Analysis
    monitor_network_traffic()
    analyze_process_behavior()
    track_file_system_changes()
    
    // Indicators of Compromise (IoCs)
    IF detect_unusual_outbound_traffic() THEN
        flag_potential_c2_communication()
    END IF
    
    IF detect_privilege_escalation_attempts() THEN
        alert_security_team()
    END IF
    
    IF detect_lateral_movement_patterns() THEN
        isolate_affected_systems()
    END IF
    
    // Threat Hunting
    correlate_events_across_systems()
    analyze_timeline_of_activities()
    investigate_anomalous_behaviors()
END

Algorithm Network_Intrusion_Detection:
Input: network_packet_stream
Output: intrusion_alerts[]

BEGIN
    signature_database = load_attack_signatures()
    anomaly_baseline = establish_network_baseline()
    
    FOR EACH packet IN network_packet_stream DO
        // Signature-based Detection
        FOR EACH signature IN signature_database DO
            IF packet_matches_signature(packet, signature) THEN
                generate_alert("Known Attack Pattern", signature.name, HIGH)
                block_traffic(packet.source_ip) // IPS function
            END IF
        END FOR
        
        // Anomaly-based Detection
        packet_features = extract_features(packet)
        deviation_score = calculate_deviation(packet_features, anomaly_baseline)
        
        IF deviation_score > ANOMALY_THRESHOLD THEN
            generate_alert("Anomalous Behavior", packet_features, MEDIUM)
            IF deviation_score > CRITICAL_THRESHOLD THEN
                quarantine_source(packet.source_ip)
            END IF
        END IF
        
        // Behavioral Analysis
        update_connection_state(packet)
        IF detect_port_scan(packet.source_ip) THEN
            generate_alert("Port Scan Detected", packet.source_ip, HIGH)
        END IF
        
        IF detect_ddos_pattern(packet_stream) THEN
            activate_ddos_mitigation()
            generate_alert("DDoS Attack", "Multiple Sources", CRITICAL)
        END IF
    END FOR
END

Host-based Intrusion Detection Algorithm:
Algorithm HIDS_Monitor:
BEGIN
    baseline_state = create_system_baseline()
    
    WHILE system_running DO
        // File Integrity Monitoring
        FOR EACH critical_file IN monitored_files DO
            current_hash = calculate_hash(critical_file)
            IF current_hash != baseline_hash[critical_file] THEN
                generate_alert("File Modified", critical_file, HIGH)
                log_modification_details(critical_file)
            END IF
        END FOR
        
        // Process Monitoring
        current_processes = get_running_processes()
        FOR EACH process IN current_processes DO
            IF is_suspicious_process(process) THEN
                analyze_process_behavior(process)
                IF is_malicious_behavior() THEN
                    terminate_process(process)
                    generate_alert("Malicious Process", process.name, CRITICAL)
                END IF
            END IF
        END FOR
        
        // Registry Monitoring (Windows)
        IF detect_registry_changes() THEN
            analyze_registry_modifications()
            IF is_unauthorized_change() THEN
                revert_registry_change()
                generate_alert("Registry Tampering", modified_key, HIGH)
            END IF
        END IF
        
        // Network Connection Monitoring
        active_connections = get_network_connections()
        FOR EACH connection IN active_connections DO
            IF is_suspicious_connection(connection) THEN
                analyze_traffic_patterns(connection)
                IF is_c2_communication() THEN
                    block_connection(connection)
                    generate_alert("C2 Communication", connection.remote_ip, CRITICAL)
                END IF
            END IF
        END FOR
        
        sleep(monitoring_interval)
    END WHILE
END

Security Information and Event Management (SIEM):
Algorithm SIEM_Event_Correlation:
Input: security_events[]
Output: correlated_incidents[]

BEGIN
    event_buffer = initialize_circular_buffer(BUFFER_SIZE)
    correlation_rules = load_correlation_rules()
    
    FOR EACH event IN security_events DO
        event_buffer.add(event)
        normalize_event(event)  // Standardize format
        enrich_event(event)     // Add context information
        
        FOR EACH rule IN correlation_rules DO
            matching_events = find_matching_events(event_buffer, rule)
            
            IF rule.condition_met(matching_events) THEN
                incident = create_incident(matching_events, rule)
                calculate_risk_score(incident)
                assign_priority(incident)
                
                IF incident.priority >= AUTO_RESPONSE_THRESHOLD THEN
                    execute_automated_response(incident)
                END IF
                
                notify_security_analysts(incident)
                correlated_incidents.add(incident)
            END IF
        END FOR
    END FOR
    
    RETURN correlated_incidents
END

Operating System Hardening Checklist:

Algorithm OS_Security_Hardening:
BEGIN
    // 1. Update Management
    enable_automatic_security_updates()
    install_latest_patches()
    configure_update_schedule("daily", "critical_patches")
    
    // 2. Service Management
    unnecessary_services = identify_unnecessary_services()
    FOR EACH service IN unnecessary_services DO
        disable_service(service)
        log_hardening_action("Service Disabled", service.name)
    END FOR
    
    // 3. Network Security
    configure_firewall_rules([
        "DENY ALL incoming by default",
        "ALLOW specific required ports",
        "DENY unused protocols",
        "ENABLE connection logging"
    ])
    
    disable_unused_network_protocols()
    configure_network_segmentation()
    
    // 4. User Account Security
    enforce_password_policy({
        minimum_length: 12,
        complexity_required: true,
        password_history: 24,
        max_age_days: 90,
        account_lockout: {
            threshold: 5,
            duration: 30,
            reset_time: 30
        }
    })
    
    disable_default_accounts()
    remove_unused_user_accounts()
    configure_privileged_access_management()
    
    // 5. File System Security
    set_secure_file_permissions()
    encrypt_sensitive_directories()
    configure_file_integrity_monitoring()
    
    // 6. Audit Configuration
    enable_comprehensive_logging([
        "Authentication events",
        "Privilege escalation attempts", 
        "File access attempts",
        "Network connections",
        "System configuration changes"
    ])
    
    configure_log_retention(365)  // days
    setup_log_forwarding("central_siem_server")
    
    // 7. Application Security
    install_endpoint_protection()
    configure_application_whitelisting()
    enable_data_execution_prevention()
    configure_address_space_layout_randomization()
    
    // 8. Physical Security
    configure_screen_lock_timeout(300)  // 5 minutes
    disable_usb_autorun()
    encrypt_full_disk()
    configure_secure_boot()
END

Network Security Architecture:
Algorithm Network_Segmentation_Design:
BEGIN
    // DMZ Configuration
    dmz = create_network_segment("DMZ", "192.168.10.0/24")
    place_in_dmz([web_servers, email_servers, dns_servers])
    
    // Internal Network Segmentation
    user_network = create_segment("Users", "10.0.1.0/24")
    server_network = create_segment("Servers", "10.0.2.0/24") 
    admin_network = create_segment("Admin", "10.0.3.0/24")
    guest_network = create_segment("Guest", "10.0.4.0/24")
    
    // Firewall Rules Configuration
    configure_inter_segment_rules([
        "Users → Internet: HTTP/HTTPS only",
        "Users → Servers: Specific application ports",
        "Admin → All: Full access with logging",
        "Guest → Internet: HTTP/HTTPS with content filtering",
        "Guest → Internal: DENY ALL",
        "DMZ → Internal: DENY ALL",
        "Servers → Internet: Updates and backups only"
    ])
    
    // Intrusion Prevention System
    deploy_ips_sensors([
        dmz.gateway,
        internal_network.gateway,
        critical_server_segment.gateway
    ])
    
    // Network Access Control (NAC)
    configure_802_1x_authentication()
    implement_device_profiling()
    enforce_compliance_policies()
END

Zero Trust Architecture Implementation:
Algorithm Zero_Trust_Access_Control:
Input: access_request
Output: access_decision

BEGIN
    // Never Trust, Always Verify
    user_identity = authenticate_user(access_request.user)
    IF user_identity == NULL THEN
        RETURN DENY
    END IF
    
    device_trust = assess_device_trust(access_request.device)
    location_risk = calculate_location_risk(access_request.location)
    behavior_score = analyze_user_behavior(user_identity, access_request)
    
    // Least Privilege Access
    required_permissions = get_minimum_required_permissions(access_request.resource)
    user_permissions = get_user_permissions(user_identity)
    
    IF NOT has_sufficient_permissions(user_permissions, required_permissions) THEN
        RETURN DENY
    END IF
    
    // Risk Assessment
    total_risk_score = calculate_risk_score(device_trust, location_risk, behavior_score)
    
    IF total_risk_score > HIGH_RISK_THRESHOLD THEN
        require_additional_authentication()
        IF NOT additional_auth_successful() THEN
            RETURN DENY
        END IF
    ELSE IF total_risk_score > MEDIUM_RISK_THRESHOLD THEN
        apply_additional_monitoring(access_request)
    END IF
    
    // Grant Conditional Access
    access_token = create_conditional_access_token(
        user_identity, 
        required_permissions,
        time_limit,
        network_restrictions
    )
    
    log_access_grant(access_request, total_risk_score)
    RETURN GRANT(access_token)
END

Container-Based Sandboxing Algorithm:

Algorithm Container_Sandbox_Creation:
Input: application_binary, security_policy, resource_limits
Output: isolated_container

BEGIN
    // Create new namespace for isolation
    container_namespace = create_namespace([
        PID_NAMESPACE,     // Process isolation
        NET_NAMESPACE,     // Network isolation  
        MNT_NAMESPACE,     // File system isolation
        IPC_NAMESPACE,     // Inter-process communication isolation
        UTS_NAMESPACE,     // Hostname isolation
        USER_NAMESPACE     // User ID isolation
    ])
    
    // Set up cgroup resource limits
    cgroup_config = {
        memory_limit: resource_limits.memory,
        cpu_quota: resource_limits.cpu_percent,
        io_bandwidth: resource_limits.io_rate,
        network_bandwidth: resource_limits.network_rate
    }
    
    container_cgroup = create_cgroup(cgroup_config)
    
    // Configure security constraints
    seccomp_filter = create_seccomp_filter([
        "SCMP_ACT_ALLOW: read, write, open, close",
        "SCMP_ACT_DENY: ptrace, mount, reboot",
        "SCMP_ACT_KILL: execve /bin/sh"  // Prevent shell access
    ])
    
    // Set up capabilities
    capabilities = drop_capabilities([
        CAP_SYS_ADMIN,     // System administration
        CAP_NET_ADMIN,     // Network administration
        CAP_SYS_MODULE,    // Load kernel modules
        CAP_SYS_RAWIO,     // Raw I/O access
        CAP_SYS_TIME       // Set system time
    ])
    
    // Create read-only root filesystem
    rootfs = create_overlay_filesystem(
        base_image,
        writable_layer,
        READ_ONLY_BASE
    )
    
    // Launch container process
    container_process = fork_process()
    
    IF container_process == CHILD THEN
        // Child process - becomes the container
        setns(container_namespace)
        join_cgroup(container_cgroup)
        apply_seccomp_filter(seccomp_filter)
        set_capabilities(capabilities)
        chroot(rootfs)
        exec(application_binary)
    ELSE
        // Parent process - monitor container
        monitor_container_health(container_process)
        enforce_resource_limits(container_cgroup)
        log_container_events(container_process.pid)
    END IF
    
    RETURN container_process.pid
END

Virtual Machine-Based Isolation:
Algorithm VM_Sandbox_Creation:
BEGIN
    // Hypervisor-based isolation
    vm_config = {
        memory_size: "512MB",
        disk_size: "2GB", 
        network_mode: "NAT_ISOLATED",
        cpu_count: 1,
        enable_nested_virtualization: false
    }
    
    // Create minimal VM image
    base_image = create_minimal_image([
        "kernel_image",
        "init_system", 
        "basic_utilities",
        "target_application"
    ])
    
    // Configure security policies
    vm_security_policy = {
        disable_usb: true,
        disable_cd_rom: true,
        disable_floppy: true,
        enable_secure_boot: true,
        disable_debug_interfaces: true
    }
    
    // Launch isolated VM
    vm_instance = hypervisor.create_vm(vm_config, base_image)
    hypervisor.apply_security_policy(vm_instance, vm_security_policy)
    hypervisor.start_vm(vm_instance)
    
    // Monitor VM behavior
    setup_vm_monitoring(vm_instance, [
        "network_traffic",
        "file_system_changes", 
        "process_creation",
        "system_calls"
    ])
    
    RETURN vm_instance
END

Application Sandboxing Comparison:
┌─────────────────────┬─────────────────┬─────────────────────┬──────────────┐
│     Technology      │   Performance   │    Isolation Level  │  Use Cases   │
├─────────────────────┼─────────────────┼─────────────────────┼──────────────┤
│ Containers          │ Low overhead    │ Process-level       │ Microservices│
│ Virtual Machines    │ High overhead   │ Hardware-level      │ Legacy apps  │
│ seccomp-bpf         │ Minimal         │ System call filter  │ Browsers     │
│ AppArmor/SELinux    │ Low overhead    │ Mandatory AC        │ System daemons│
│ Windows Sandbox     │ Medium overhead │ Lightweight VM      │ Document viewers│
└─────────────────────┴─────────────────┴─────────────────────┴──────────────┘

Secure Boot Process Algorithm:

Algorithm Secure_Boot_Process:
BEGIN
    // Phase 1: Hardware Root of Trust
    cpu_microcode = verify_cpu_microcode_signature()
    IF NOT cpu_microcode.valid THEN
        halt_boot("Invalid CPU microcode")
    END IF
    
    // Phase 2: UEFI Firmware Verification
    uefi_firmware = load_uefi_firmware()
    firmware_signature = extract_signature(uefi_firmware)
    
    IF NOT verify_signature(firmware_signature, platform_key) THEN
        halt_boot("UEFI firmware signature invalid")
    END IF
    
    // Phase 3: Boot Loader Verification  
    bootloader_candidates = scan_for_bootloaders()
    
    FOR EACH bootloader IN bootloader_candidates DO
        bootloader_signature = extract_signature(bootloader)
        
        IF verify_signature(bootloader_signature, key_exchange_key) THEN
            trusted_bootloader = bootloader
            BREAK
        END IF
    END FOR
    
    IF trusted_bootloader == NULL THEN
        halt_boot("No trusted bootloader found")
    END IF
    
    // Phase 4: OS Kernel Verification
    kernel_image = load_kernel_from_bootloader()
    kernel_signature = extract_signature(kernel_image)
    
    IF NOT verify_signature(kernel_signature, authorized_db) THEN
        IF signature_in_forbidden_db(kernel_signature) THEN
            halt_boot("Kernel in forbidden signature database")
        ELSE
            prompt_user_for_override()
        END IF
    END IF
    
    // Phase 5: Initialize Trusted Platform Module (TPM)
    tpm_initialize()
    pcr_values = extend_pcr_measurements([
        firmware_hash,
        bootloader_hash,
        kernel_hash,
        kernel_command_line_hash
    ])
    
    store_measurements_in_tpm(pcr_values)
    
    // Phase 6: Transfer Control to Kernel
    setup_secure_memory_regions()
    enable_memory_protection()
    transfer_control_to_kernel(kernel_image)
END

Trusted Platform Module (TPM) Integration:
Algorithm TPM_Attestation:
Input: attestation_request
Output: attestation_report

BEGIN
    // Collect Platform Configuration Registers (PCR) values
    pcr_values = read_pcr_registers([0, 1, 2, 3, 4, 5, 6, 7])
    
    // Create attestation identity key
    aik = tpm_create_attestation_identity_key()
    
    // Generate quote (signed PCR values)
    nonce = attestation_request.nonce
    quote = tpm_quote(pcr_values, nonce, aik)
    
    // Collect additional system information
    system_info = {
        firmware_version: get_firmware_version(),
        os_version: get_os_version(),
        security_patches: get_installed_patches(),
        running_processes: get_critical_processes(),
        loaded_drivers: get_loaded_drivers()
    }
    
    // Create comprehensive attestation report
    attestation_report = {
        quote: quote,
        pcr_values: pcr_values,
        system_information: system_info,
        timestamp: get_current_timestamp(),
        tpm_public_key: aik.public_key
    }
    
    // Sign the report with TPM
    report_signature = tpm_sign(attestation_report, aik.private_key)
    attestation_report.signature = report_signature
    
    RETURN attestation_report
END

Remote Attestation Verification:
Algorithm Verify_Remote_Attestation:
Input: attestation_report, trusted_pcr_baseline
Output: trust_decision

BEGIN
    // Verify TPM quote signature
    IF NOT verify_tpm_signature(attestation_report.quote, attestation_report.tpm_public_key) THEN
        RETURN UNTRUSTED("Invalid TPM signature")
    END IF
    
    // Verify TPM certificate chain
    IF NOT verify_tpm_certificate_chain(attestation_report.tpm_public_key) THEN
        RETURN UNTRUSTED("Invalid TPM certificate")
    END IF
    
    // Compare PCR values against known good baseline
    FOR EACH pcr_index IN [0, 1, 2, 3, 4, 5, 6, 7] DO
        measured_value = attestation_report.pcr_values[pcr_index]
        baseline_value = trusted_pcr_baseline[pcr_index]
        
        IF measured_value != baseline_value THEN
            log_pcr_deviation(pcr_index, measured_value, baseline_value)
            
            IF pcr_index IN critical_pcrs THEN
                RETURN UNTRUSTED("Critical PCR deviation detected")
            END IF
        END IF
    END FOR
    
    // Verify system configuration
    IF NOT verify_system_configuration(attestation_report.system_information) THEN
        RETURN CONDITIONAL_TRUST("System configuration concerns")
    END IF
    
    RETURN TRUSTED("Attestation verified successfully")
END

Machine Learning-Based Anomaly Detection:

Algorithm ML_Anomaly_Detection_Training:
Input: historical_network_traffic, normal_behavior_labels
Output: trained_anomaly_model

BEGIN
    // Feature extraction from network traffic
    features = extract_features(historical_network_traffic, [
        "packet_size_distribution",
        "inter_arrival_times", 
        "protocol_distribution",
        "source_destination_patterns",
        "payload_entropy",
        "connection_duration",
        "bytes_per_session"
    ])
    
    // Normalize features for ML processing
    normalized_features = standardize_features(features)
    
    // Train isolation forest for anomaly detection
    isolation_forest = IsolationForest(
        n_estimators=100,
        contamination=0.1,  // Expected anomaly rate
        random_state=42
    )
    
    isolation_forest.fit(normalized_features, normal_behavior_labels)
    
    // Train autoencoder for reconstruction-based detection
    autoencoder = create_autoencoder_model(
        input_dimension=normalized_features.shape[1],
        hidden_layers=[64, 32, 16, 32, 64],
        activation="relu"
    )
    
    autoencoder.train(
        training_data=normalized_features,
        epochs=100,
        batch_size=32,
        validation_split=0.2
    )
    
    // Calculate reconstruction error threshold
    reconstruction_errors = autoencoder.predict(normalized_features)
    anomaly_threshold = calculate_percentile(reconstruction_errors, 95)
    
    trained_model = {
        isolation_forest: isolation_forest,
        autoencoder: autoencoder,
        feature_normalizer: get_normalizer_params(),
        anomaly_threshold: anomaly_threshold
    }
    
    RETURN trained_model
END

Algorithm Real_Time_Anomaly_Detection:
Input: live_network_stream, trained_model
Output: anomaly_alerts[]

BEGIN
    alert_buffer = initialize_buffer()
    
    FOR EACH network_packet IN live_network_stream DO
        // Extract features from current packet/flow
        current_features = extract_real_time_features(network_packet)
        normalized_features = apply_normalization(current_features, trained_model.feature_normalizer)
        
        // Isolation Forest scoring
        isolation_score = trained_model.isolation_forest.decision_function(normalized_features)
        
        // Autoencoder reconstruction error
        reconstructed = trained_model.autoencoder.predict(normalized_features)
        reconstruction_error = calculate_mse(normalized_features, reconstructed)
        
        // Combine scores for final anomaly decision
        combined_score = 0.6 * isolation_score + 0.4 * reconstruction_error
        
        IF combined_score > trained_model.anomaly_threshold THEN
            anomaly_alert = {
                timestamp: get_current_time(),
                source_ip: network_packet.source,
                destination_ip: network_packet.destination,
                anomaly_score: combined_score,
                suspicious_features: identify_contributing_features(current_features),
                raw_packet_data: network_packet,
                confidence_level: calculate_confidence(combined_score)
            }
            
            alert_buffer.add(anomaly_alert)
            
            // Trigger immediate response for high-confidence anomalies
            IF anomaly_alert.confidence_level > HIGH_CONFIDENCE_THRESHOLD THEN
                trigger_immediate_response(anomaly_alert)
            END IF
        END IF
        
        // Update model with recent data (online learning)
        IF should_update_model() THEN
            retrain_model_incrementally(normalized_features)
        END IF
    END FOR
    
    RETURN alert_buffer.get_all()
END

User and Entity Behavior Analytics (UEBA):
Algorithm UEBA_Profile_Creation:
Input: user_activity_logs, time_window
Output: user_behavior_baseline

BEGIN
    user_profiles = {}
    
    FOR EACH user IN get_all_users() DO
        user_activities = filter_activities_by_user(user_activity_logs, user)
        
        // Temporal patterns
        login_patterns = analyze_login_patterns(user_activities, [
            "login_times",
            "login_frequency", 
            "session_duration",
            "source_locations"
        ])
        
        // Access patterns
        access_patterns = analyze_access_patterns(user_activities, [
            "files_accessed",
            "applications_used",
            "network_resources",
            "permission_escalations"
        ])
        
        // Behavioral metrics
        behavioral_metrics = calculate_behavioral_metrics(user_activities, [
            "typing_patterns",
            "mouse_movement_patterns",
            "application_usage_sequences",
            "data_volume_transferred"
        ])
        
        // Risk scoring
        baseline_risk_score = calculate_baseline_risk(user, [
            "role_permissions",
            "access_to_sensitive_data",
            "administrative_privileges",
            "historical_incidents"
        ])
        
        user_profile = {
            user_id: user,
            login_patterns: login_patterns,
            access_patterns: access_patterns, 
            behavioral_metrics: behavioral_metrics,
            baseline_risk_score: baseline_risk_score,
            profile_creation_date: get_current_date(),
            confidence_level: calculate_profile_confidence(user_activities.length)
        }
        
        user_profiles[user] = user_profile
    END FOR
    
    RETURN user_profiles
END