Choose a guide by the question you need to answer: how cryptography works, how to protect a file or message, how to review an implementation, or how to interpret quantum-security and policy claims. Each resource connects the explanation to a practical decision or a worked example.
Foundations and data protection
Cryptography Explained: Encryption, Hashes, Signatures, and Keys
Match cryptographic tools to confidentiality, integrity and authentication, and understand how keys and protocols bring them together.
Data Security: Protect Files, Recovery, and Disposal
Map important information, control access, protect storage and transfers, test recovery, and choose a documented disposal process.
Secret Code Machines: Randomness, One-Time Pads, and Security Claims
Understand what makes a code machine secure, why one-time pads require careful key handling, and how to assess claims of unbreakable encryption.
Communication and implementations
Email Encryption: Choose a Method and Verify Delivery
Choose a supported email-encryption workflow, verify the recipient, and test messages, attachments and recovery before sending sensitive information.
Secure Messaging: Choose a Channel and Verify the Recipient
Choose a channel, verify the recipient, and account for copies, backups and access after delivery.
XML Encryption: Protect Fields and Review Integrations
Trace encrypted XML fields, distinguish encryption from signature verification, and review the configuration of a maintained integration.
IBM Z Encryption: Coverage, Keys, and Recovery Planning
Map encryption layers on IBM Z, understand z/OS data-set key dependencies, and plan a staged deployment with recovery evidence.
Quantum security and cryptographic operations
Quantum Cryptography: QKD, Eavesdropping Tests, and Post-Quantum Security
Understand how quantum key distribution works, what its security assumptions mean, and how it differs from post-quantum cryptography.
Quantum Key Infrastructure: Evaluate QKD, PKI, and Migration
Evaluate quantum key distribution as a complete network service, including authentication, trusted nodes, key delivery, outages and post-quantum alternatives.
10 Ways AI is Changing Encryption Tech
Explore AI assistance for cryptographic inventory, key hygiene, configuration review and post-quantum planning, with human verification.
History and policy
U.S. Encryption Policy: History and How to Check Export Rules
Understand the historical encryption-policy debate and organize the facts needed to find current U.S. export-control guidance.
How the pieces connect
Encryption protects confidentiality; hashes summarize bytes; signatures connect signed content to a key; and key management controls how those keys are generated, used, recovered and retired. Trustworthy identity checks and sound software make these tools useful together.
For implementation topics beyond encryption, explore Programming.