kb/data/developer.mozilla.org/en-US/docs/Glossary/Nonce-0.md

title	chunk	source	category	tags	date_saved	instance
Nonce - Glossary | MDN	1/3	https://developer.mozilla.org/en-US/docs/Glossary/Nonce	reference	web, html, css, javascript, documentation	2026-05-05T05:38:51.919318+00:00	kb-cron

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1. Glossary
2. Nonce

Nonce

In cryptography and computer security, a nonceis an arbitrary number that is usedonly once in a cryptographic communication. The term is derived from "number used once" and is commonly employed to prevent replay attacks, ensure message freshness, and add randomness to cryptographic protocols. Nonces are frequently used in authentication protocols, encryption schemes, hashing, and digital signatures. They may be generated randomly or pseudo-randomly, or derived deterministically, depending on the application and security requirements. In web security, nonces are commonly used in mechanisms such as Content Security Policy (CSP) to allow specific scripts to execute while preventing cross-site scripting (XSS) attacks. In cryptographic protocols like TLS, nonces help ensure that each session is unique.

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• See also

See also

• Cryptographic nonce on Wikipedia
• Content Security Policy (CSP)
• Replay attack on Wikipedia
• Related glossary terms:
  • cryptography
  • encryption
  • hash
  • TLS
  • authentication