Nonce
A value used only once within the scope a cryptographic construction requires. Some schemes need only uniqueness and others unpredictability; reusing an AES-GCM nonce with the same key breaks both confidentiality and authenticity.
- Defined in
- NIST glossary: nonce
Covered in
AEAD records: AES-GCM nonces, associated data and key limits
Build an encrypted record whose tag binds ciphertext to the intended tenant, record, purpose and format, keep nonces unique within each key’s usage limit, and verify the design with actual AES-GCM.
Configure HTTP security headers from a tested baseline
Send the response headers that make browsers enforce HTTPS, run only your own scripts, refuse hostile framing and keep cookies on one host, then prove they appear on every kind of response.
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A sourced quick reference for October 2026: which algorithm and parameters to use for encryption, hashing, passwords, MACs, signatures, key agreement, key derivation, randomness and TLS, the matching APIs in Node.js, Python, Java, Go and .NET, and where post-quantum migration stands.
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The four smart-contract attack classes beyond reentrancy: price-oracle manipulation, flash-loan amplification, upgradeable-proxy storage collisions and uninitialized implementations, and signature replay, each with vulnerable and fixed Solidity, Foundry tests and verified incidents.
WEP: RC4 key reuse and weak IVs
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Configure CORS and CSP around the browser capabilities you need
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All 10 pages that cover Nonce in the library
Practice: AES-GCM nonce reuse lab: Fix a nonce allocator that breaks after restart · CORS policy lab: Grant CORS to the right origins only · CSP builder lab: Build a strict Content-Security-Policy · Insecure randomness lab: Generate unguessable API keys