Skip to content

Latest commit

 

History

History
348 lines (284 loc) · 29.8 KB

sec-design.md

File metadata and controls

348 lines (284 loc) · 29.8 KB

Project Design Document: Crypto++ Library

Project Name: Crypto++ Library

Project Repository: https://github.com/weidai11/cryptopp

Document Version: 1.1 Date: October 26, 2023 Author: AI Cybersecurity Expert

1. Project Overview

1.1. Project Goal

The Crypto++ library is a free C++ class library providing a comprehensive suite of cryptographic algorithms and primitives. Its primary goal is to empower developers with a robust, performant, and readily accessible cryptographic toolkit for building secure applications. It aims to be a reliable and standards-compliant resource for implementing cryptography in C++ projects.

1.2. Project Scope

This design document details the architecture and design of the Crypto++ library to facilitate threat modeling. It provides a structured overview of the library's components, data flow, security boundaries, and key security considerations.

The scope includes:

  • Comprehensive Cryptographic Algorithm Suite: Symmetric ciphers (AES, DES, ChaCha20, etc.), asymmetric ciphers (RSA, ECC, etc.), hash functions (SHA-2, SHA-3, Blake2, etc.), MACs (HMAC, CMAC, etc.), digital signatures (DSA, ECDSA, etc.), key exchange (DH, ECDH, etc.), and password-based key derivation functions (PBKDFs).
  • Essential Supporting Infrastructure: Cryptographically Secure Pseudo-Random Number Generators (CSPRNGs), in-memory key management utilities, data encoding/decoding schemes (Base64, Hex, ASN.1, DER, PEM), and optimized modular arithmetic operations.
  • Well-Defined C++ APIs: Object-oriented and procedural C++ interfaces designed for ease of use and integration into various applications. This includes both high-level abstractions and lower-level access for advanced users.
  • Build System and Minimal Dependencies: Focus on a portable and easily buildable library with minimal external dependencies to reduce the attack surface and simplify deployment.
  • Error Handling and Reporting: Mechanisms for reporting errors and exceptions during cryptographic operations.
  • Configuration and Customization Options: Exploring potential configuration options such as algorithm selection at compile-time or runtime, and build options for specific features.

The scope explicitly excludes:

  • Security of Applications Using Crypto++: This document does not assess the security of applications that integrate Crypto++. Secure application design and proper library usage are the responsibility of the application developer.
  • Detailed Vulnerability Analysis: This document prepares for threat modeling but does not perform a specific vulnerability assessment or penetration testing.
  • Performance Benchmarking and Optimization Details: While performance is a consideration, detailed performance analysis and optimization strategies are outside the scope.
  • Source Code Level Review: This is a design-level document, not a detailed code walkthrough or static analysis report.
  • External Persistent Key Storage: Crypto++ focuses on in-memory key management. External key storage solutions are application-specific and not covered here.

1.3. Target Audience

This document is intended for:

  • Security Professionals (Architects, Engineers, Threat Modelers): To understand the Crypto++ library's architecture for security analysis, threat modeling, and risk assessment.
  • Software Developers Using Crypto++: To gain a deeper understanding of the library's design, security features, and proper usage for building secure applications.
  • Crypto++ Project Maintainers and Contributors: To serve as a design reference for ongoing development, maintenance, and security enhancements.
  • Auditors and Reviewers: To evaluate the security design and architecture of the Crypto++ library.

2. System Architecture

2.1. High-Level Architecture Diagram

graph LR
    subgraph "Crypto++ Library"
    subgraph "Core Cryptographic Modules"
        A["Algorithm Implementations"]
        B["Key Management"]
        C["Random Number Generation (RNG)"]
        E["Modular Arithmetic"]
    end
    D["Data Encoding/Decoding"]
    F["Interfaces/APIs"]
    G["Error Handling"]
    H["Configuration"]
    end

    F --> A
    F --> B
    F --> C
    F --> D
    F --> G
    F --> H
    A --> E
    B --> E
    C --> A
    C --> B

    style "Crypto++ Library" fill:#f9f,stroke:#333,stroke-width:2px
    style "Core Cryptographic Modules" fill:#ccf,stroke:#333,stroke-dasharray: 5 5
Loading

Description:

The Crypto++ library is architected around modularity and separation of concerns, comprising the following key modules:

  • Core Cryptographic Modules (Sub-graph):

    • Algorithm Implementations: Contains the C++ implementations of a wide range of cryptographic algorithms, categorized by type (symmetric, asymmetric, hash, MAC, signature, key exchange, PBKDF).
    • Key Management: Handles in-memory key generation, representation (as objects), and basic key lifecycle management within the library's scope. It does not include persistent key storage.
    • Random Number Generation (RNG): Provides cryptographically secure random number generation, crucial for key generation, initialization vectors, and other security-sensitive operations. It aims to leverage OS-provided entropy sources where available.
    • Modular Arithmetic: Offers optimized implementations of modular arithmetic operations, essential for many public-key cryptographic algorithms.

  • Data Encoding/Decoding: Provides utilities for converting cryptographic data to and from various encoding formats (Base64, Hex, ASN.1, DER, PEM) for storage, transmission, and interoperability.

  • Interfaces/APIs: Exposes the C++ APIs (classes and functions) that developers use to interact with the library's cryptographic functionalities. These APIs are designed to be both user-friendly and flexible.

  • Error Handling: Provides mechanisms for reporting errors and exceptions that may occur during cryptographic operations, allowing applications to handle errors gracefully.

  • Configuration: (Potentially) Offers configuration options to customize library behavior, such as selecting specific algorithms or enabling/disabling features at compile-time or runtime.

Data Flow:

The typical data flow within the library involves:

  1. API Request: An application initiates a cryptographic operation by calling a Crypto++ API function (e.g., encryption, hashing, signing).
  2. API Routing and Parameter Handling: The API layer parses the request, validates parameters, and routes it to the appropriate algorithm implementation within the "Algorithm Implementations" module.
  3. Key Retrieval and Management: The algorithm implementation interacts with the "Key Management" module to retrieve the necessary cryptographic keys. Key generation might also be initiated through the API and handled by the "Key Management" and "RNG" modules.
  4. Randomness Generation (if required): If the cryptographic operation requires randomness (e.g., key generation, IV generation, padding), the "RNG" module is invoked to generate cryptographically secure random data.
  5. Modular Arithmetic Operations (if required): For algorithms relying on modular arithmetic (e.g., RSA, ECC), the "Modular Arithmetic" module performs the necessary computations.
  6. Cryptographic Processing: The "Algorithm Implementations" module executes the core cryptographic algorithm using the input data, keys, random data (if any), and modular arithmetic operations (if any).
  7. Output Generation: The result of the cryptographic operation (ciphertext, hash, signature, etc.) is generated.
  8. Data Encoding (if requested): If the API request specifies encoding (e.g., Base64 encoding of the output), the "Data Encoding/Decoding" module is used to encode the output data.
  9. Error Handling (if necessary): If any errors occur during the process, the "Error Handling" module is used to report the error back to the application, typically through exceptions or error codes.
  10. API Response: The result (potentially encoded) is returned to the calling application through the API.

2.2. Component Details

2.2.1. Algorithm Implementations

  • Algorithm Categories:
    • Symmetric Ciphers (Block & Stream): AES (CBC, CTR, GCM, ECB, OFB), DES, Triple DES (EDE2, EDE3), Blowfish, ChaCha20, Salsa20, Serpent, Twofish, Camellia, IDEA, RC4, RC6.
    • Asymmetric Ciphers (Public-Key): RSA (PKCS#1 v1.5, OAEP, PSS), ECC (Elliptic Curve Cryptography) - ECDH, ECDSA, EdDSA (Ed25519, Ed448), Curve25519, Curve448, DSA, ElGamal.
    • Hash Functions (Cryptographic Digests): SHA-1, SHA-2 (SHA-256, SHA-384, SHA-512, SHA-512/256, SHA-512/224), SHA-3 (SHA3-256, SHA3-384, SHA3-512, SHAKE128, SHAKE256), Blake2b, Blake2s, MD5, RIPEMD-160, Whirlpool.
    • Message Authentication Codes (MACs): HMAC (Hash-based MAC), CMAC (Cipher-based MAC), Poly1305, GMAC (Galois/Counter Mode MAC).
    • Digital Signatures (Authentication & Non-Repudiation): DSA, ECDSA, EdDSA, RSA-PSS, RSA-PKCS#1 v1.5.
    • Key Agreement Protocols (Key Exchange): Diffie-Hellman (DH), Elliptic Curve Diffie-Hellman (ECDH) (various curves).
    • Password-Based Key Derivation Functions (PBKDFs): PBKDF2 (with various hash algorithms), Argon2 (Argon2i, Argon2d, Argon2id), scrypt.
  • Implementation Principles:
    • C++ Language: Primarily implemented in standard C++ (C++98/C++03 compatibility focus, with some newer features in later versions).
    • Performance Optimization: Designed for efficiency and speed, often employing platform-specific optimizations where applicable.
    • Cross-Platform Portability: Aiming for broad platform support (Windows, Linux, macOS, mobile, embedded).
    • Standards Compliance: Adherence to relevant cryptographic standards (e.g., NIST, RFCs) for algorithm implementations.
    • Code Clarity and Maintainability: Striving for well-structured and documented code for easier maintenance and auditing.

2.2.2. Key Management

  • Key Lifecycle (within library scope):
    • Generation: Key generation functions are provided for various algorithms, leveraging the CSPRNG.
    • Representation: Keys are represented as C++ objects (e.g., PrivateKey, PublicKey, SymmetricKey), encapsulating key material and associated algorithm parameters.
    • In-Memory Storage: Keys are primarily managed in memory during the application's runtime. Crypto++ does not provide built-in persistent key storage.
    • Usage: Keys are used as input parameters to cryptographic algorithm APIs for encryption, decryption, signing, verification, etc.
    • Destruction: Key objects should be securely destroyed when no longer needed to minimize the risk of key compromise from memory.
  • Key Formats (Import/Export):
    • DER (Distinguished Encoding Rules) encoded keys (binary format).
    • PEM (Privacy Enhanced Mail) encoded keys (Base64 encoded DER with headers/footers).
    • JWK (JSON Web Key) - support may vary depending on algorithm and key type.
    • Raw binary key material (for some symmetric keys).
  • Security Considerations:
    • CSPRNG Dependency: Key generation security relies entirely on the strength and proper seeding of the CSPRNG.
    • In-Memory Security: Protecting keys in memory from unauthorized access is crucial. Memory protection mechanisms of the operating system and secure coding practices are relevant.
    • Key Handling Responsibility: Secure key management practices (secure storage, secure exchange, access control, key rotation) are largely the responsibility of the application developer using Crypto++. Crypto++ provides the tools but not the complete key management system.

2.2.3. Random Number Generation (RNG)

  • CSPRNG Implementations:
    • OS-Provided RNGs: Leverages operating system APIs for CSPRNGs (e.g., /dev/urandom on Linux/Unix-like systems, CryptGenRandom on Windows).
    • Algorithm-Based DRBGs: May include Deterministic Random Bit Generators (DRBGs) based on cryptographic algorithms (e.g., AES-CTR DRBG, Hash-based DRBG) as fallbacks or alternatives.
    • Hardware RNG Integration (potential): Possibility to integrate with hardware random number generators if available on the target platform (though not a primary focus).
  • Entropy Sources:
    • Relies on operating system entropy sources (e.g., system noise, hardware events) to seed the CSPRNGs.
    • Seed management and reseeding strategies are important for maintaining randomness quality.
  • Security Criticality:
    • RNG is a foundational security component. Compromise of the RNG directly undermines the security of many cryptographic operations.
    • Ensuring sufficient entropy for seeding and continuous operation of the CSPRNG is paramount.
  • Security Considerations:
    • Entropy Source Reliability: Dependence on OS-provided entropy sources. Ensuring these sources are reliable and provide sufficient entropy.
    • CSPRNG Algorithm Strength: Using well-vetted and strong CSPRNG algorithms.
    • Seeding and Reseeding: Proper initial seeding and periodic reseeding of the CSPRNG to maintain randomness quality.
    • State Protection: Protecting the internal state of the CSPRNG from unauthorized access or modification.

2.2.4. Data Encoding/Decoding

  • Supported Encoding Schemes:
    • Base64: Encoding binary data into ASCII characters.
    • Hexadecimal (Hex): Encoding binary data as hexadecimal digits.
    • ASN.1 (Abstract Syntax Notation One): A standard for defining data structures, used for encoding cryptographic objects (certificates, keys).
    • DER (Distinguished Encoding Rules): A binary encoding rule for ASN.1.
    • PEM (Privacy Enhanced Mail): A container format using Base64 encoding with headers and footers, commonly used for keys and certificates.
  • Functionality:
    • Encoding: Converting binary cryptographic data (e.g., keys, ciphertext, signatures) into encoded formats for storage, transmission, or display.
    • Decoding: Parsing encoded data back into binary form for cryptographic processing.
    • Format Conversion: Potentially supporting conversion between different encoding formats (e.g., DER to PEM).
  • Security Considerations:
    • Correct Implementation: Ensuring correct implementation of encoding/decoding algorithms to avoid data corruption or misinterpretation.
    • Input Validation: Validating encoded input data to prevent parsing errors or vulnerabilities.
    • Canonicalization (for ASN.1/DER): Ensuring canonical encoding for ASN.1/DER to prevent signature bypass vulnerabilities.

2.2.5. Modular Arithmetic

  • Arithmetic Operations:
    • Modular addition, subtraction, multiplication, exponentiation, inversion, division, reduction.
    • Greatest Common Divisor (GCD), Extended Euclidean Algorithm.
    • Primality testing, prime number generation (to a limited extent, primarily for testing).
  • Optimization Techniques:
    • Efficient algorithms for large integer arithmetic (e.g., Karatsuba multiplication, Montgomery multiplication, Barrett reduction).
    • Assembly language optimizations for performance-critical operations on specific platforms (potentially).
  • Data Types:
    • Representation of large integers (bignums) to handle the large numbers used in public-key cryptography.
  • Security Considerations:
    • Correctness of Implementation: Ensuring the correctness of modular arithmetic implementations is critical for the security of algorithms relying on them.
    • Side-Channel Resistance (potential): For some algorithms, side-channel resistance (e.g., timing attack resistance) in modular exponentiation might be considered, although this is a complex area.
    • Integer Overflow/Underflow Prevention: Careful handling of large integer arithmetic to prevent overflows or underflows that could lead to incorrect results or vulnerabilities.

2.2.6. Interfaces/APIs

  • API Styles:
    • Object-Oriented: Classes representing cryptographic algorithms (e.g., AESEncryption, RSAPrivateKey), modes of operation, and keys.
    • Procedural/Functional: Functions for performing specific cryptographic operations (e.g., Encrypt(), Hash(), Sign()).
    • Streaming APIs: Support for processing data in streams, useful for large files or network data.
    • One-Shot APIs: For processing data in single blocks or messages.
  • API Design Principles:
    • Ease of Use: Designed to be relatively easy to use for developers with varying levels of cryptographic expertise.
    • Flexibility: Providing sufficient flexibility for advanced users to customize cryptographic operations and parameters.
    • Clarity and Consistency: Consistent naming conventions and API design across different algorithms and functionalities.
    • Error Reporting: Clear and informative error reporting mechanisms (exceptions, error codes).
  • Documentation:
    • Comprehensive documentation (API reference, user guides, examples) is essential for proper library usage.
  • Security Considerations:
    • API Misuse Prevention: Designing APIs to minimize the risk of misuse by developers, such as providing clear usage guidelines and examples.
    • Input Validation: Performing input validation within the API layer to prevent invalid parameters or malicious inputs from reaching the core cryptographic modules.
    • Secure Defaults: Providing secure default settings and configurations where applicable.

2.2.7. Error Handling

  • Error Reporting Mechanisms:
    • Exceptions: C++ exceptions are likely used to signal errors during cryptographic operations (e.g., invalid key, invalid input data, algorithm failure).
    • Return Codes/Status Codes: Potentially using return codes or status codes in some APIs for error indication.
  • Error Types:
    • Invalid key errors
    • Invalid input data errors (e.g., incorrect padding, invalid ciphertext format)
    • Algorithm-specific errors
    • Resource allocation errors
    • Configuration errors
  • Error Handling Best Practices:
    • Providing informative error messages to aid debugging and troubleshooting.
    • Ensuring that error handling does not introduce new vulnerabilities (e.g., information leaks in error messages).
    • Allowing applications to gracefully handle errors and recover or terminate securely.

2.2.8. Configuration

  • Configuration Options (Potential):
    • Algorithm Selection: Options to select specific algorithms or algorithm variants at compile-time or runtime (e.g., choosing between different AES implementations, enabling/disabling certain algorithms).
    • Build Options: CMake build options to enable/disable features, optimize for specific platforms, or control dependencies.
    • Runtime Configuration (limited): Runtime configuration might be limited, but could include options for setting RNG sources or choosing specific algorithm parameters where applicable.
  • Configuration Management:
    • CMake build system for managing build configurations.
    • Potentially using configuration files or environment variables for runtime configuration (less likely for a library focused on core crypto).
  • Security Considerations:
    • Secure Defaults: Ensuring secure default configurations.
    • Configuration Validation: Validating configuration settings to prevent invalid or insecure configurations.
    • Minimizing Attack Surface: Configuration options should be designed to minimize the attack surface by allowing users to disable unused features or algorithms.

3. Technology Stack

  • Programming Language: C++ (Primarily C++98/C++03, aiming for broad compiler compatibility. Later versions may incorporate newer C++ features incrementally).
  • Build System:
    • GNU Make: Traditional Makefiles for build automation.
    • CMake: Cross-platform build system generator, supporting various IDEs and compilers.
  • Minimal Dependencies:
    • Standard C++ Library: Relies on the standard C++ library.
    • Operating System APIs: Uses OS-specific APIs for CSPRNG access (e.g., /dev/urandom, CryptGenRandom).
    • Optional Dependencies: Potentially zlib for optional compression features (e.g., for some archive formats, not core crypto). Dependencies are kept to an absolute minimum to reduce complexity and potential vulnerabilities.
  • Supported Platforms:
    • Operating Systems: Windows, Linux, macOS, iOS, Android, *BSD variants, and various other Unix-like systems.
    • Architectures: x86, x86-64, ARM (various architectures), PowerPC, and others.
    • Compilers: GCC, Clang, Visual C++, Intel C++ Compiler, and other C++ compilers supporting the required C++ standards.

4. Deployment Environment

  • Deployment Model: Crypto++ is a C++ library intended for integration into other applications. It is compiled and linked into the application's executable or shared library.
  • Target Applications:
    • Desktop applications (Windows, macOS, Linux)
    • Server-side applications (web servers, backend services)
    • Mobile applications (iOS, Android)
    • Embedded systems (IoT devices, firmware)
    • Cloud services and infrastructure
    • Command-line tools and utilities
    • Any software requiring cryptographic functionality in C++.
  • Environment Security Considerations:
    • Secure Operating System: Deployment on a secure and hardened operating system is crucial.
    • Memory Protection: Operating system memory protection mechanisms help protect keys and sensitive data in memory.
    • Process Isolation: Process isolation can limit the impact of vulnerabilities in other parts of the system.
    • Secure Key Storage (Application Responsibility): Applications using Crypto++ must implement secure key storage mechanisms if persistent key storage is required. Crypto++ itself does not provide this.
    • Secure Communication Channels (Application Responsibility): Applications are responsible for establishing and using secure communication channels (e.g., TLS/SSL) when transmitting cryptographic data.

5. Security Considerations

5.1. General Security Principles

  • Cryptographic Algorithm Strength: Reliance on the inherent strength of well-established and vetted cryptographic algorithms. Security depends on choosing appropriate algorithms for the specific security requirements.
  • Implementation Correctness and Security: Emphasis on writing correct and secure C++ code to prevent implementation vulnerabilities (buffer overflows, memory leaks, integer overflows, timing attacks, etc.).
  • Strong Randomness: Critical dependence on a robust and properly seeded CSPRNG for key generation, IV generation, and other security-sensitive operations.
  • Secure Key Management (Library Scope): Providing tools for secure in-memory key management within the library's scope, but clearly defining the application's responsibility for broader key management.
  • Side-Channel Attack Awareness: Consideration of side-channel attacks (timing attacks, power analysis, etc.) in algorithm implementations, although full side-channel resistance is a complex and ongoing challenge.
  • Regular Security Audits and Reviews: Importance of regular security audits, code reviews, and vulnerability assessments to identify and address potential security issues.
  • Timely Security Updates and Patching: Providing timely security updates and patches to address reported vulnerabilities.
  • Clear Documentation and Secure Usage Guidance: Providing clear and comprehensive documentation and secure usage guidelines to help developers use the library correctly and avoid common pitfalls.
  • Minimal Attack Surface: Keeping the library's codebase and dependencies minimal to reduce the potential attack surface.

5.2. Potential Security Risks (Specific Examples)

  • Algorithm-Specific Vulnerabilities:
    • Weak Algorithm Usage: Using deprecated or weak algorithms (e.g., MD5 for collision resistance, single DES) where stronger alternatives are available.
    • Incorrect Algorithm Parameters: Using insecure or inappropriate algorithm parameters (e.g., short key lengths, weak elliptic curves).
    • Protocol-Level Vulnerabilities: Vulnerabilities arising from incorrect implementation or usage of cryptographic protocols (e.g., incorrect padding schemes, flawed key exchange protocols).
  • Implementation Vulnerabilities:
    • Buffer Overflows: Potential buffer overflows in C++ code handling input data or cryptographic operations.
    • Memory Leaks: Memory leaks leading to resource exhaustion or potential information leaks.
    • Integer Overflows/Underflows: Integer overflows or underflows in modular arithmetic or other numerical computations.
    • Timing Attacks: Timing variations in algorithm implementations potentially leaking information about keys or plaintext.
    • Fault Injection Attacks (less likely in software, but possible in certain environments): Vulnerabilities to fault injection attacks that could manipulate cryptographic operations.
  • RNG-Related Risks:
    • Insufficient Entropy: Failure to seed the CSPRNG with sufficient entropy, leading to predictable random numbers.
    • RNG State Compromise: Compromise of the CSPRNG state, allowing attackers to predict future random numbers.
    • RNG Algorithm Weakness: Using a weak or flawed CSPRNG algorithm.
  • Key Management Risks (Library Scope):
    • Insecure Key Generation: Using weak or predictable random numbers for key generation due to RNG issues.
    • In-Memory Key Exposure: Keys in memory potentially being exposed through memory dumps, debugging tools, or other attacks.
    • Insufficient Key Destruction: Keys not being securely erased from memory after use.
  • API Misuse Risks:
    • Incorrect API Usage: Developers misusing the Crypto++ APIs, leading to insecure cryptographic implementations in their applications (e.g., using ECB mode for AES when CTR or GCM is more appropriate).
    • Parameter Validation Failures: Insufficient input validation in application code leading to vulnerabilities when using Crypto++ APIs.
    • Ignoring Error Handling: Applications not properly handling errors reported by Crypto++, potentially leading to security failures.
  • Dependency Risks (Minimal, but still relevant):
    • Vulnerabilities in minimal external dependencies (if any) could indirectly affect Crypto++.

6. Threat Model Scope

The threat model based on this design document will focus on the Crypto++ library as a cryptographic component itself. The primary focus will be on threats that directly target the library's functionalities and internal workings.

In-Scope Threats:

  • Threats to the Confidentiality, Integrity, and Availability of cryptographic operations performed by Crypto++. This includes threats targeting encryption, decryption, hashing, signing, key exchange, and other cryptographic functionalities provided by the library.
  • Threats arising from implementation vulnerabilities within the Crypto++ library's code and design. This includes buffer overflows, memory leaks, integer overflows, timing attacks, and other code-level vulnerabilities within the library itself.
  • Threats related to the secure generation and handling of cryptographic keys within the library's scope. This focuses on the security of key generation processes and in-memory key management within Crypto++, acknowledging that application-level persistent key storage is out of scope.
  • Threats related to the quality and security of the Random Number Generator (RNG) used by Crypto++. This includes threats targeting the entropy source, CSPRNG algorithm, seeding, and state management of the RNG.
  • Threats arising from API misuse due to unclear or insecure API design within Crypto++. This focuses on potential vulnerabilities caused by developers misusing the library's APIs in ways that were not intended or anticipated by the library designers.
  • Threats related to vulnerabilities in minimal external dependencies (if any) of Crypto++.

Out-of-Scope Threats:

  • Threats to applications that use Crypto++ due to application-level vulnerabilities or misuse of the library. This includes vulnerabilities in application logic, insecure key storage implemented by the application, insecure communication channels used by the application, and general application security flaws that are not directly related to Crypto++ itself.
  • Threats to the infrastructure where applications using Crypto++ are deployed. This includes operating system vulnerabilities, network security issues, physical security threats, and other infrastructure-level threats.
  • Social engineering or physical attacks targeting developers or systems using Crypto++.
  • Denial-of-service attacks that target the application using Crypto++, but are not directly related to vulnerabilities within Crypto++ itself. (DoS attacks against Crypto++ library itself, if any, would be in scope).
  • Performance-related threats that do not directly lead to security vulnerabilities. (e.g., slow performance of cryptographic operations is not a primary security threat in itself, unless it enables other attacks).

This refined design document provides a more detailed and structured foundation for conducting a targeted and effective threat modeling exercise specifically focused on the Crypto++ library's security. The next step is to use this document to systematically identify specific threats, vulnerabilities, and attack vectors within the defined scope.