Threat Model
============

Comprehensive threat model for Sudarshan Engine's quantum-safe cybersecurity architecture.

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Overview
========

This document outlines the threat model for Sudarshan Engine, identifying potential attack vectors, security assumptions, and mitigation strategies. The threat model covers both current classical attacks and future quantum computing threats.

Security Objectives
===================

**Confidentiality**
   Ensure that encrypted data remains confidential against both classical and quantum attacks.

**Integrity**
   Protect data integrity and detect any unauthorized modifications.

**Authentication**
   Verify the authenticity of data origin and prevent impersonation attacks.

**Non-Repudiation**
   Prevent parties from denying the authenticity of their signatures.

**Forward Secrecy**
   Ensure that compromise of long-term keys doesn't affect past communications.

**Quantum Resistance**
   Maintain security guarantees even against large-scale quantum computers.

Attack Vectors
==============

**1. Cryptographic Attacks**

**Quantum Attacks:**
   - Shor's algorithm (discrete logarithm, factoring)
   - Grover's algorithm (key search acceleration)
   - **Mitigation:** NIST-approved PQC algorithms (Kyber, Dilithium, Falcon)

**Classical Attacks:**
   - Brute force key search
   - Dictionary attacks
   - Rainbow table attacks
   - **Mitigation:** Strong key derivation, large key spaces, salting

**Side-Channel Attacks:**
   - Timing attacks
   - Power analysis
   - Electromagnetic emanation analysis
   - **Mitigation:** Hardware isolation, constant-time operations, noise injection

**2. Protocol Attacks**

**Man-in-the-Middle (MitM):**
   - Intercept and modify communications
   - **Mitigation:** End-to-end encryption, certificate pinning, secure channels

**Replay Attacks:**
   - Capture and retransmit valid messages
   - **Mitigation:** Nonces, timestamps, sequence numbers, one-time use

**Key Reuse Attacks:**
   - Compromise security by reusing cryptographic material
   - **Mitigation:** Ephemeral keys, stateless operations, unique per operation

**3. Implementation Attacks**

**Buffer Overflow:**
   - Overwrite memory to execute arbitrary code
   - **Mitigation:** Bounds checking, safe memory operations, fuzzing

**Injection Attacks:**
   - SQL injection, command injection
   - **Mitigation:** Input validation, parameterized queries, sanitization

**Race Conditions:**
   - Concurrent access leading to security violations
   - **Mitigation:** Proper synchronization, atomic operations

**4. Physical Attacks**

**Cold Boot Attacks:**
   - Extract keys from memory after power loss
   - **Mitigation:** Memory clearing, secure boot, hardware security modules

**Bus Sniffing:**
   - Intercept data on internal buses
   - **Mitigation:** Encrypted buses, secure enclaves

**Fault Injection:**
   - Induce hardware faults to bypass security
   - **Mitigation:** Redundant checks, error detection, secure elements

**5. Supply Chain Attacks**

**Malicious Dependencies:**
   - Compromised third-party libraries
   - **Mitigation:** Dependency auditing, reproducible builds, code signing

**Build System Compromise:**
   - Tampered build environments
   - **Mitigation:** Secure CI/CD, build verification, air-gapped builds

**6. Social Engineering**

**Phishing:**
   - Trick users into revealing credentials
   - **Mitigation:** User education, multi-factor authentication

**Insider Threats:**
   - Authorized users abusing privileges
   - **Mitigation:** Least privilege, audit logging, separation of duties

Security Assumptions
====================

**Trust Assumptions:**

1. **Hardware Trust:**
   - CPU and memory are not compromised at the physical level
   - Hardware security modules (HSM/TPM) are genuine and not backdoored
   - Secure enclaves (SGX/TEE) provide genuine isolation

2. **Software Trust:**
   - Operating system kernel is not compromised
   - Sudarshan Engine binaries are authentic and unmodified
   - Python interpreter and standard libraries are secure

3. **Network Trust:**
   - Initial installation occurs over secure channels
   - Certificate authorities are trustworthy
   - DNS resolution is not compromised

4. **User Trust:**
   - Users choose strong, unique passwords
   - Users protect their cryptographic keys appropriately
   - Users do not run Sudarshan Engine on compromised systems

**Environmental Assumptions:**

1. **Threat Actor Capabilities:**
   - Access to large-scale quantum computers (post-2025)
   - Advanced classical computing resources
   - Physical access to target systems (limited scenarios)
   - Network interception capabilities

2. **Operational Environment:**
   - Systems connected to untrusted networks
   - Multi-user systems with potential insider threats
   - Systems with varying hardware security capabilities

3. **Compliance Requirements:**
   - GDPR, HIPAA, PCI DSS, SOX compliance where applicable
   - Industry-specific security standards

Box-in-a-Box Defense Strategy
=============================

Sudarshan Engine implements a multi-layered defense strategy:

**Layer 1: Inner Shield**
   - **Purpose:** Protect legacy assets with PQC wrappers
   - **Threats Addressed:** Legacy crypto compromise, key extraction
   - **Controls:** Kyber KEM, Dilithium signatures, abstraction layers

**Layer 2: Outer Vault**
   - **Purpose:** Multi-factor authentication and access control
   - **Threats Addressed:** Unauthorized access, credential theft
   - **Controls:** MFA, PQC signatures, hardware tokens, session management

**Layer 3: Isolation Room**
   - **Purpose:** Hardware-secured cryptographic operations
   - **Threats Addressed:** Side-channel attacks, memory scraping
   - **Controls:** HSM/TPM integration, secure enclaves, isolation

**Layer 4: Transaction Capsule**
   - **Purpose:** Stateless, one-time cryptographic operations
   - **Threats Addressed:** Key reuse, replay attacks, state compromise
   - **Controls:** Ephemeral keys, unique operations, non-repudiation

Cryptographic Security Analysis
===============================

**Algorithm Selection:**

**Key Encapsulation (Kyber):**
   - **Security Level:** IND-CCA2 secure
   - **Quantum Resistance:** Module-LWE problem hardness
   - **Performance:** Fast key agreement
   - **Variants:** Kyber512, Kyber768, Kyber1024

**Digital Signatures (Dilithium/Falcon):**
   - **Security Level:** EUF-CMA secure
   - **Quantum Resistance:** MLWE/MSIS problem hardness
   - **Performance:** Dilithium (balanced), Falcon (fast verification)
   - **Key Sizes:** Dilithium (1312B public), Falcon (897B public)

**Symmetric Encryption (AES-256-GCM/ChaCha20-Poly1305):**
   - **Security Level:** IND-CPA secure
   - **Quantum Resistance:** Grover's algorithm provides quadratic speedup
   - **Performance:** Hardware accelerated
   - **Authenticated:** Built-in integrity protection

**Hash Functions (SHA3-512):**
   - **Security Level:** Collision/preimage resistant
   - **Quantum Resistance:** Grover's algorithm provides quadratic speedup
   - **Performance:** Hardware accelerated
   - **Output Size:** 512 bits

**Key Derivation (HKDF):**
   - **Security Level:** PRF secure
   - **Quantum Resistance:** Based on SHA3
   - **Purpose:** Derive multiple keys from shared secret

Attack Mitigation Matrix
========================

.. list-table::
   :header-rows: 1
   :widths: 20 15 15 15 15

   * - Attack Type
     - Inner Shield
     - Outer Vault
     - Isolation Room
     - Transaction Capsule
   * - Quantum Attacks
     - ✅ PQC Algorithms
     - ✅ PQC Signatures
     - ✅ Hardware Security
     - ✅ Ephemeral Keys
   * - Side-Channel
     - ⚠️ Partial
     - ⚠️ Partial
     - ✅ Hardware Isolation
     - ✅ Stateless Ops
   * - Replay Attacks
     - ⚠️ Partial
     - ✅ Sequence Numbers
     - ✅ Hardware Tokens
     - ✅ One-Time Use
   * - Key Reuse
     - ⚠️ Partial
     - ✅ Session Keys
     - ✅ Hardware Keys
     - ✅ Unique Keys
   * - Physical Attacks
     - ❌ None
     - ❌ None
     - ✅ Secure Enclaves
     - ⚠️ Partial
   * - Insider Threats
     - ⚠️ Partial
     - ✅ Access Control
     - ✅ Audit Logging
     - ✅ Non-Repudiation

Risk Assessment
===============

**High Risk Threats:**

1. **Quantum Computing Breakthrough**
   - **Likelihood:** Medium (2025-2030)
   - **Impact:** High
   - **Mitigation:** PQC algorithms, algorithm agility
   - **Status:** ✅ Addressed

2. **Supply Chain Compromise**
   - **Likelihood:** Low-Medium
   - **Impact:** Critical
   - **Mitigation:** Dependency auditing, reproducible builds
   - **Status:** ✅ Addressed

3. **Advanced Persistent Threats (APT)**
   - **Likelihood:** Medium
   - **Impact:** High
   - **Mitigation:** Multi-layer defense, anomaly detection
   - **Status:** ✅ Addressed

**Medium Risk Threats:**

1. **Side-Channel Attacks**
   - **Likelihood:** Medium
   - **Impact:** Medium-High
   - **Mitigation:** Hardware isolation, constant-time operations
   - **Status:** ✅ Addressed

2. **Implementation Vulnerabilities**
   - **Likelihood:** Medium
   - **Impact:** Medium
   - **Mitigation:** Code review, fuzzing, static analysis
   - **Status:** ✅ Addressed

3. **Denial of Service**
   - **Likelihood:** High
   - **Impact:** Medium
   - **Mitigation:** Rate limiting, resource controls
   - **Status:** ✅ Addressed

**Low Risk Threats:**

1. **Classical Cryptanalysis**
   - **Likelihood:** Low
   - **Impact:** Low
   - **Mitigation:** Strong algorithms, large key sizes
   - **Status:** ✅ Addressed

2. **Social Engineering**
   - **Likelihood:** High
   - **Impact:** Low-Medium
   - **Mitigation:** User education, MFA
   - **Status:** ✅ Addressed

Security Monitoring and Response
================================

**Continuous Monitoring:**

1. **Runtime Security Monitoring:**
   - Cryptographic operation validation
   - Memory access pattern analysis
   - Network traffic inspection
   - System call monitoring

2. **Anomaly Detection:**
   - Unusual cryptographic operation patterns
   - Unexpected memory access patterns
   - Suspicious network connections
   - Abnormal resource usage

3. **Audit Logging:**
   - All security-relevant events
   - Cryptographic operation logs
   - Access attempt logs
   - System state changes

**Incident Response:**

1. **Detection Phase:**
   - Automated alert generation
   - Security event correlation
   - Threat intelligence integration

2. **Analysis Phase:**
   - Forensic data collection
   - Attack vector analysis
   - Impact assessment

3. **Containment Phase:**
   - System isolation
   - Compromised key revocation
   - Emergency backup activation

4. **Recovery Phase:**
   - System restoration
   - Security patch deployment
   - Lesson learned documentation

Compliance and Regulatory Considerations
========================================

**GDPR (General Data Protection Regulation):**
   - Data encryption at rest and in transit
   - Right to erasure (crypto-shredding)
   - Data portability (export capabilities)
   - Breach notification (automated detection)

**HIPAA (Health Insurance Portability and Accountability Act):**
   - Protected Health Information (PHI) encryption
   - Audit trail requirements
   - Access control and authentication
   - Security risk analysis

**PCI DSS (Payment Card Industry Data Security Standard):**
   - Cardholder data encryption
   - Secure key management
   - Access control requirements
   - Audit and monitoring

**SOX (Sarbanes-Oxley Act):**
   - Financial data integrity
   - Audit trail preservation
   - Access control and segregation
   - Change management

Future Threat Landscape
=======================

**Emerging Threats (2025-2030):**

1. **Large-Scale Quantum Computing:**
   - **Impact:** Break current public-key cryptography
   - **Mitigation:** PQC algorithm migration, hybrid schemes

2. **AI-Powered Attacks:**
   - **Impact:** Automated vulnerability discovery
   - **Mitigation:** AI-assisted defense, automated patching

3. **Supply Chain Attacks:**
   - **Impact:** Compromised dependencies and build tools
   - **Mitigation:** Software Bill of Materials (SBOM), secure supply chain

4. **IoT and Edge Computing Threats:**
   - **Impact:** Compromised edge devices
   - **Mitigation:** Device attestation, secure boot

**Long-term Considerations (2030+):**

1. **Post-Quantum Cryptography Evolution:**
   - New PQC algorithms as research advances
   - Migration strategies for existing deployments

2. **Homomorphic Encryption:**
   - Computation on encrypted data
   - Privacy-preserving analytics

3. **Multi-Party Computation:**
   - Secure computation across multiple parties
   - Distributed trust models

4. **Blockchain Integration:**
   - Decentralized key management
   - Smart contract security

Conclusion
==========

Sudarshan Engine's threat model provides comprehensive protection against both current and future threats through:

- **Multi-layered defense architecture**
- **Quantum-resistant cryptographic primitives**
- **Hardware-assisted security isolation**
- **Continuous monitoring and response**
- **Regulatory compliance support**

The threat model is regularly updated to address emerging threats and incorporate lessons learned from security incidents.

.. note::
   This threat model is based on current understanding of attack vectors and defense capabilities. It should be reviewed and updated regularly as the threat landscape evolves.

.. tip::
   For specific security requirements or custom threat models, contact Sudarshan Engine's security team for professional consultation.

.. warning::
   No security system is completely impervious. Defense in depth and regular security assessments are essential for maintaining security over time.