Today, cryptography protects the confidentiality and integrity of data in all states. Modern cryptographic functions are provided by well-established libraries, one of which is OpenSSL. It is imperative to understand how the pieces fit together, as misusing them can completely nullify the protections applied.

This course explores practical cryptography from the ground up, combining theory, practice using OpenSSL, and real-life case studies. First, we define secure-communication requirements (e.g. confidentiality, integrity) and transition into cryptographic primitives and their properties. Participants learn about symmetric encryption modes, hashing, message authentication codes (MACs), and correct usage. Next, asymmetric encryption is introduced, exploring RSA, DSA, and ECC. We then see how these building blocks construct the Public Key Infrastructure (PKI), certificates, and root of trust. At last, we build the TLS protocol and examine some of its vulnerabilities.

The course is invaluable for anyone working directly or indirectly with cryptographic functions. Following the practices and recommendations in this course ensures that cryptography applied will genuinely serve its function and protect data as intended.

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