up:: [[Introduction to Cryptography]] # Cryptography Cryptography is the practice and study of techniques for secure communication in the presence of third parties called adversaries. Its main goal is to ensure the confidentiality, integrity, authenticity, and non-repudiation of information and communications through the use of mathematical theories and computational algorithms. ## Key Features - **[[Encryption]]:** The process of converting plain text into a scrambled cipher text that can only be read if decrypted. - **Decryption:** The process of converting encrypted text back into its original form (plain text). - **[[Hash Function|Hash Functions]]:** Produce a unique fixed-size hash value from data of any size, which is commonly used in creating digital signatures and data integrity verification. - **Key Management:** The secure management of cryptographic keys including their generation, storage, distribution, and destruction. ## How It Works Cryptography is implemented through two main types of algorithms: - **Symmetric Key Cryptography:** Uses the same key for both encryption and decryption. This key must be shared between the communicating parties without being intercepted. - **Asymmetric Key Cryptography:** Uses a pair of keys, a public key and a private key. The public key is shared with everyone, while the private key remains confidential. Data encrypted with the public key can only be decrypted with the private key and vice versa. ## Problem Addressed Cryptography addresses the security challenges in communicating over unsecured channels, protecting sensitive data against unauthorized access, and verifying the authenticity of a message or sender in digital communications. ## Implications Effective cryptography ensures the security of digital transactions, protects data privacy, secures software and digital identities, and supports the foundation of internet security protocols like SSL/TLS for secure browsing, email encryption, and more. ## Impact Cryptography underpins the security framework of the digital age, enabling e-commerce, secure communications, and the safekeeping of sensitive information across various sectors including banking, healthcare, and government. ## Defense Mechanisms - **Cryptographic Protocols:** Such as SSL/TLS and IPsec that protect data in transit. - **Digital Signatures:** Provide a means to check the authenticity of digital messages and documents, ensuring that they have not been altered in transit. - **Certificates and PKI:** Manage key exchange and authentication in digital communications. ## Exploitable Mechanisms/Weaknesses Cryptographic systems can be compromised through key mismanagement, use of weak or outdated algorithms, or through breakthroughs in computational power such as quantum computing, which could potentially break current encryption methods. ## Common Tools/Software - **OpenSSL:** Provides robust cryptographic functions to secure communications. - **GnuPG:** A free implementation of the OpenPGP standard for encrypting and signing data. - **Cryptographic Libraries:** Such as Crypto++, a C++ library of cryptographic algorithms. ## Related Cybersecurity Policies - **NIST Cryptographic Standards and Guidelines:** Provide comprehensive guidance on cryptographic methods for federal information systems, including NIST SP 800-57 (Recommendations for Key Management). - **ISO/IEC 27002:** Provides best practice recommendations on information security controls including cryptography. - **General Data Protection Regulation (GDPR):** Encourages encryption as a measure to protect personal data and ensure privacy. ## Best Practices - Regularly update cryptographic systems and algorithms to guard against vulnerabilities. - Implement strong key management practices to protect and handle cryptographic keys securely. - Stay informed about advances in cryptography and computational capabilities that may affect current cryptographic techniques. ## Current Status Cryptography is continuously evolving with advancements in technology. Research in quantum-resistant cryptography is particularly active, in anticipation of quantum computing becoming a viable threat to current encryption methods. ## Revision History - **2024-04-14:** Entry created.