> For the complete documentation index, see [llms.txt](https://libsodium.gitbook.io/doc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://libsodium.gitbook.io/doc/public-key_cryptography.md).

# Public-key cryptography

*Public-key cryptography* refers to cryptographic systems that require two different keys, linked together by some one-way mathematical relationship, which depends on the algorithm used. The private key cannot be recovered from the public key.