Custom Cryptography

Custom cryptography refers to the design and implementation of cryptographic algorithms, protocols, or systems from scratch, rather than using established, standardized solutions. It involves creating bespoke encryption, hashing, or authentication mechanisms tailored to specific, often niche, requirements. This practice is generally discouraged in most scenarios due to the high risk of introducing security vulnerabilities through design flaws or implementation errors.

Also known as: Bespoke Cryptography, Homemade Cryptography, Roll-Your-Own Cryptography, Proprietary Cryptography, Custom Crypto

Why learn Custom Cryptography?

Developers should only consider custom cryptography in rare, highly specialized cases where no existing standard meets unique constraints, such as extreme performance needs in embedded systems or proprietary hardware with unusual architectures. It is primarily used in academic research, cryptographic competitions, or when developing novel cryptographic primitives for future standardization. In all other situations, developers should rely on well-vetted, industry-standard libraries like OpenSSL or libsodium to ensure security and interoperability.

Learning Resources

• book: Cryptography Engineering: Design Principles and Practical Applications
• docs: NIST Cryptographic Standards and Guidelines
• course: Cryptography I by Stanford University (Coursera)
• tutorial: Why You Shouldn't Roll Your Own Crypto
• video: Introduction to Modern Cryptography