Encrypt Online
Theme

Reference library

Cryptography courses, books, standards, and labs

Browse trusted material from original publishers. This is a reference shelf, not a required sequence. For one recommendation, return to the three starting points.

New to cryptography

Foundations

Beginner-friendly explanations of classical ciphers, modular arithmetic, RSA, and Diffie-Hellman.

  1. Khan Academy

    Khan Academy Cryptography

    The clearest no-background route into classical ciphers, modular arithmetic, RSA, and Diffie-Hellman.

    • Course unit
    • Beginner
    • Free
    • Video, text, and exercises
    Availability and source notes
    Text support
    Individual video lessons provide a Transcript tab; the unit also includes written explanations.
    Status
    Established introductory unit; several lessons are older
    Reuse
    Publisher terms; link to the original lessons.
  2. Christof Paar

    Understanding Cryptography online course

    A complete applied sequence that reaches modern cryptography without requiring advanced mathematics at the start.

    • Lecture course
    • Beginner to intermediate
    • Free
    • Video and slides
    Availability and source notes
    Text support
    The course page links slides; caption quality and availability vary by video.
    Status
    Maintained author course page
    Reuse
    Publisher terms; link to the course and slide sources.
  3. CrypTool Project

    CrypTool Online

    Visual transformations make abstract cipher operations easier to recognize before writing code.

    • Interactive lab
    • Beginner
    • Free
    • Browser exercises and visual tools
    Availability and source notes
    Text support
    Written interface guidance is available; this is an interactive resource rather than a transcript-led course.
    Status
    Maintained project
    Reuse
    Project terms; link to the original tools.
  4. MIT OpenCourseWare

    Mathematics for Computer Science: Lecture 10, Cryptography

    A compact, rigorous bridge from modular arithmetic to the ideas behind RSA.

    • University lecture
    • Beginner to intermediate
    • Free
    • Video, transcript, and notes
    Availability and source notes
    Text support
    The lecture page provides an official transcript and lecture notes.
    Status
    Spring 2024 OCW course material
    Reuse
    MIT OpenCourseWare terms; link only from this ad-supported site.

Programmers

Coding practice

Courses and challenge labs that turn cryptographic ideas and failure modes into working code.

  1. CryptoHack

    CryptoHack Introduction

    It provides more scaffolding than most challenge sets while still teaching through adversarial practice.

    • Interactive course
    • Beginner programmer
    • Free to read; account required to submit flags and save progress
    • Written lessons and Python challenges
    Availability and source notes
    Text support
    The core lessons are available as written text.
    Status
    Maintained challenge platform
    Reuse
    Site terms; link to challenges and do not publish flags or solutions.
  2. Laurens Van Houtven

    Crypto 101

    A friendly explanation of primitives and common attacks for readers who already think in software systems.

    • Free CC-licensed book
    • Beginner to intermediate
    • Free
    • PDF and source repository
    Availability and source notes
    Text support
    The book provides the complete written material.
    Status
    Classic systems-oriented text; pair with current standards
    Reuse
    CC BY-NC 4.0; link and cite, and do not adapt here without suitable permission.
  3. Dan Boneh, Stanford University

    Stanford Online Cryptography

    The strongest compact structure for modern symmetric and public-key cryptography, attacks, and protocols.

    • University course
    • Intermediate
    • Free public course index
    • Video, slides, readings, exercises, and projects
    Availability and source notes
    Text support
    Slides and readings provide a stable text route; caption availability varies across hosted videos.
    Status
    Public Stanford course archive
    Reuse
    University and author terms; link to the original material.
  4. Cryptopals

    The Cryptopals Crypto Challenges

    The attack-driven sets turn details such as padding, nonce reuse, and oracles into durable engineering intuition.

    • Challenge series
    • Intermediate
    • Free
    • Coding exercises
    Availability and source notes
    Text support
    The challenges use written prompts.
    Status
    Maintained challenge collection
    Reuse
    Site terms; link to challenges and do not publish solutions.
  5. Arizona State University

    pwn.college Cryptography

    It connects primitive-level concepts to concrete security failures in a realistic command-line environment.

    • University lab course
    • Intermediate
    • Free; registration required to launch workspaces and submit solutions
    • Lectures, slides, shell work, and Python challenges
    Availability and source notes
    Text support
    Slides support the lectures; caption availability can vary by recording.
    Status
    Maintained course platform
    Reuse
    Course terms; link to the original modules and challenges.
  6. SEED Project, Syracuse University

    SEED Cryptography Labs

    The labs cover modes, padding oracles, hashes, RSA, signatures, PKI, and TLS with reproducible exercises.

    • University lab collection
    • Intermediate
    • Free
    • Downloadable lab manuals and environments
    Availability and source notes
    Text support
    Detailed written lab manuals serve as the primary teaching material.
    Status
    Ubuntu 20.04 lab series
    Reuse
    Open educational materials; check each lab's terms before reuse.

Developers and security engineers

Production guidance

Maintained libraries, key-management guidance, and practical advice for deployed systems.

  1. Alfred Menezes

    Applied Cryptography 101: Real-World Deployments

    It studies PKI, TLS 1.3, KMS, Signal, and other deployments where operational choices shape security.

    • Practitioner course
    • Intermediate
    • Free
    • Video and slides
    Availability and source notes
    Text support
    Slides provide a text route; caption availability varies by lecture.
    Status
    April 2025 course
    Reuse
    Author terms; link to the course and slide sources.
  2. libsodium

    libsodium Quickstart

    High-level, misuse-resistant APIs show what a production abstraction should remove from application code.

    • Implementation reference
    • Intermediate
    • Free
    • Text and code
    Availability and source notes
    Text support
    Fully written documentation with code examples.
    Status
    Maintained documentation
    Reuse
    Documentation terms; link to the current quickstart.
  3. Python Cryptographic Authority

    pyca/cryptography documentation

    Its recipes-versus-hazardous-materials boundary is a useful model for choosing safer application APIs.

    • Implementation reference
    • Intermediate
    • Free
    • Text and code
    Availability and source notes
    Text support
    Fully written documentation with recipes and lower-level reference material.
    Status
    Stable documentation channel
    Reuse
    Documentation terms; link to the maintained version.
  4. NIST SP 800-57 Part 1 Rev. 5

    Recommendation for Key Management: Part 1

    It adds lifecycle, governance, protection, and transition context that primitive tutorials rarely cover.

    • NIST recommendation
    • Practitioner
    • Free
    • Landing page, full text, and PDF
    Availability and source notes
    Text support
    The publication provides the authoritative written material.
    Status
    Final publication
    Reuse
    NIST terms; cite the landing page and do not imply validation or endorsement.
  5. OWASP Cheat Sheet Series

    Cryptographic Storage Cheat Sheet

    A concise checkpoint for threat modeling, algorithm choice, randomness, storage, and key handling.

    • Practitioner guidance
    • Intermediate
    • Free
    • Web text
    Availability and source notes
    Text support
    The cheat sheet is fully available as web text.
    Status
    Maintained community guidance
    Reuse
    Project terms; link to the current cheat sheet.

Students and researchers

Theory and proofs

Textbooks for definitions, security games, reductions, number theory, and modern constructions.

  1. Mike Rosulek

    The Joy of Cryptography

    The most approachable first source for formal definitions, security games, and game-hopping proofs.

    • Online textbook
    • Undergraduate
    • Free to read online
    • Web text, animations, and exercises
    Availability and source notes
    Text support
    The website is the current text; older PDFs elsewhere may not match it.
    Status
    Current online edition
    Reuse
    CC BY-NC-ND 4.0; link and cite without adapting its text, figures, or exercises.
  2. Dan Boneh and Victor Shoup

    A Graduate Course in Applied Cryptography

    A comprehensive modern reference spanning core primitives, elliptic curves, lattices, protocols, threshold cryptography, and MPC.

    • Graduate textbook
    • Advanced
    • Free author draft
    • PDF and exercises
    Availability and source notes
    Text support
    The complete author-distributed book is available as a PDF.
    Status
    Version 0.6 draft, January 2023
    Reuse
    Author terms; link to the canonical book page and PDF.
  3. Boaz Barak

    An Intensive Introduction to Cryptography

    It extends a rigorous core into zero knowledge, MPC, FHE, quantum topics, obfuscation, anonymity, and ethics.

    • Course text
    • Advanced
    • Free
    • Web text and exercises
    Availability and source notes
    Text support
    The evolving course text is fully readable online.
    Status
    Work in progress
    Reuse
    CC BY-NC-ND 4.0; link and cite without adapting the material.
  4. Victor Shoup

    A Computational Introduction to Number Theory and Algebra

    A strong foundation for the algebra and number-theoretic algorithms used throughout public-key cryptography.

    • Mathematics textbook
    • Intermediate to advanced
    • Free for personal study
    • PDF
    Availability and source notes
    Text support
    The author-distributed book is the complete text.
    Status
    Stable author resource
    Reuse
    Author terms; link to the canonical book page.
  5. Mihir Bellare and Phillip Rogaway

    Introduction to Modern Cryptography

    A historically important game-based treatment whose older algorithm examples should be checked against current standards.

    • Course notes
    • Advanced
    • Free
    • PDF
    Availability and source notes
    Text support
    The course notes provide the complete written material.
    Status
    Foundational legacy notes
    Reuse
    Author terms; link to the original PDF.

Technical leads and security teams

Post-quantum transition

Standards, migration planning, and technical introductions to post-quantum cryptography.

  1. Alfred Menezes

    Post-Quantum Cryptography Explained

    A non-mathematical orientation to the threat, standardization story, deployment choices, and migration problem.

    • Practitioner course
    • Intermediate
    • Free
    • Video and slides
    Availability and source notes
    Text support
    Slides provide a text route; caption availability varies by lecture.
    Status
    Maintained author course
    Reuse
    Author terms; link to the original course material.
  2. Alfred Menezes

    Kyber and Dilithium

    A bridge from lattice foundations and the NTT to the standardized ML-KEM and ML-DSA families.

    • Advanced applied course
    • Advanced
    • Free
    • Video, slides, and notes
    Availability and source notes
    Text support
    Slides and lecture notes support the videos; captions can vary.
    Status
    Maintained author course
    Reuse
    Author terms; link to the original course material.
  3. NIST

    Post-Quantum Cryptography project

    The primary place to confirm the status of ML-KEM, ML-DSA, SLH-DSA, future standards, and official updates.

    • Standards hub
    • Practitioner to advanced
    • Free
    • Web text, publications, presentations, and events
    Availability and source notes
    Text support
    Use the written status pages and publication links as the primary sources.
    Status
    Current standards project
    Reuse
    NIST terms; cite landing pages and do not imply validation or endorsement.
  4. Daniele Micciancio, UC San Diego

    Lattice cryptography resource index

    A strong route from foundational lattice problems into learning with errors and lattice-based constructions.

    • Study index
    • Advanced
    • Free
    • Papers, notes, books, and courses
    Availability and source notes
    Text support
    A curated text index; each linked resource has its own format and terms.
    Status
    Author-maintained resource index
    Reuse
    Author and linked-source terms; use as a directory, not material to republish.
  5. NIST Cybersecurity White Paper 39

    Considerations for Achieving Crypto Agility

    It keeps the migration path focused on inventory, policy, observability, and replaceability rather than algorithm selection alone.

    • Migration guidance
    • Practitioner
    • Free
    • Landing page, full text, and PDF
    Availability and source notes
    Text support
    The publication is the authoritative written material.
    Status
    Final updated publication
    Reuse
    NIST terms; cite the landing page and do not imply endorsement.

Advanced students and researchers

Research directions

Advanced courses and entry points for zero knowledge, secure computation, side channels, and current papers.

  1. MIT OpenCourseWare 6.5630

    Advanced Topics in Cryptography

    A coherent path through interactive proofs, PCPs, Fiat-Shamir, zero knowledge, BARGs, and SNARGs.

    • Graduate course
    • Advanced
    • Free
    • Video, transcripts, notes, and assignments
    Availability and source notes
    Text support
    Lecture pages provide downloadable text or transcript resources where listed.
    Status
    Fall 2023 OCW course
    Reuse
    MIT OpenCourseWare terms; link only from this ad-supported site.
  2. Berkeley RDI

    Zero-Knowledge Proofs MOOC

    A focused modern route from proof systems to the concepts used in current zero-knowledge protocols.

    • Specialization course
    • Advanced
    • Free
    • Video, notes, and exercises
    Availability and source notes
    Text support
    Course notes and exercises accompany the videos; caption availability varies.
    Status
    Maintained learning program
    Reuse
    Publisher terms; link to the course and original material.
  3. David Evans, Vladimir Kolesnikov, and Mike Rosulek

    A Pragmatic Introduction to Secure Multi-Party Computation

    A practical specialization in secure computation after the reader already understands core cryptographic definitions.

    • Specialist textbook
    • Advanced
    • Free author-distributed text
    • Web and PDF
    Availability and source notes
    Text support
    The complete book is available in written form.
    Status
    Stable author resource
    Reuse
    Author terms; link to the canonical book page and PDF.
  4. MIT OpenCourseWare 6.858

    Side-Channel Attacks

    A necessary reminder that sound mathematics can still fail through side-channel leakage such as timing, cache behavior, and power consumption.

    • Focused university lecture
    • Advanced
    • Free
    • Video and official transcript
    Availability and source notes
    Text support
    The lecture page provides an official transcript.
    Status
    Fall 2014 OCW lecture
    Reuse
    MIT OpenCourseWare terms; link only from this ad-supported site.
  5. International Association for Cryptologic Research

    Cryptology ePrint Archive

    The best route into current research once the reader can distinguish a preprint from a reviewed or final publication.

    • Research archive
    • Advanced
    • Free
    • Research papers
    Availability and source notes
    Text support
    Papers are the primary text; formats and accessibility vary by author submission.
    Status
    Current preprint archive; entries may precede peer review
    Reuse
    Author and paper-specific terms; link to records and verify final versions.

Source policy

How this library is maintained

We prefer author, university, standards-body, and maintained project pages. Selection does not imply endorsement. We link to the original material instead of copying transcripts, slides, chapters, exercises, flags, or solutions.

iTunes U ended in 2021, so current university pages replace its former listings. Commercial marketplaces are omitted because pricing, access, and transcript availability change frequently.

Confirm current parameters in the NIST Cryptographic Standards and Guidelines. Review our security boundaries before using browser tools with sensitive material.

External links reviewed . Found a moved source or inaccurate note? Send a correction without including secrets.