Just let's crypt

Famous and well known crypt libraries

https://bouncycastle.org/

https://www.gnutls.org/

https://git.lysator.liu.se/nettle/nettle

https://www.wolfssl.com/

https://www.cs.auckland.ac.nz/~pgut001/cryptlib/

https://gnupg.org/software/libgcrypt/

https://firefox-source-docs.mozilla.org/security/nss/index.html

https://nacl.cr.yp.to/box.html

NSA presents itself as a more official organization

https://code.nsa.gov/

https://ghidra-sre.org/

https://github.com/NationalSecurityAgency

https://github.com/orgs/NationalSecurityAgency/repositories

http://nationalsecurityagency.github.io/