one-time pad

noun

: a random-number additive or mixed keying sequence to be used for a single coded message and then destroyed

Word History

Etymology

probably from its original form's being a pad of keys whose sheets were torn off and discarded after a single use

First Known Use

1953, in the meaning defined above

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now