Available for Linux, OS X and Windows. More details can be found on https://www.primx.eu/en/encryption-software/zed-en/
ALGORITHMS: AES (128 to 256 bits) and RSA (1024 to 4096 bits).
TECHNOLOGIES: PKCS#1, PKCS#5, PKCS#11, X509, Microsoft CSP, LDAP technologies, PKIx compatible.
 PKCS#1 RSA Cryptography Standard https://en.wikipedia.org/wiki/PKCS_1
 PKCS#5 Password-based Encryption Standard https://en.wikipedia.org/wiki/PBKDF2
 PKCS#11 Cryptographic Token Interface https://en.wikipedia.org/wiki/PKCS_11
 X509 https://en.wikipedia.org/wiki/X.509 (ITU) standard defining the format of public key certificates.
 Does CSP stand for https://en.wikipedia.org/wiki/Credential_service_provider , Cloud service provide https://mymatetech.net/what-is-microsoft-csp-ab5b80519e79 or something else?
 LDAP https://en.wikipedia.org/wiki/Lightweight_Directory_Access_Protocol
 Does PKIx stand for https://en.wikipedia.org/wiki/X.509#PKIX_Working_Group ?

SYSTEMS: Available for Windows 11 to Windows 7, Linux (various distributions) and Mac OS.
LANGUAGES: Available in 7 languages.
ZED! mobile app for iOS and Android.

A password manager. It's a lot like pass ("the standard unix password manager") - which I have been using up 'til now - but it uses age instead of GPG to do the heavy lifting. Written in Ruby

We use rigorous formal methods to develop trustworthy software systems—systems that come with provable security, safety and reliability guarantees.

From https://www.schneier.com/blog/archives/2021/09/check-what-information-your-browser-leaks.html
https://dnsleaktest.com/ offers a similar service.

Critical review of some of the design choices made in the cryptographic tool 'age'.
There are other interesting articles, such as the three-part series
https://neilmadden.blog/2018/11/14/public-key-authenticated-encryption-and-why-you-want-it-part-i/
https://neilmadden.blog/2018/11/26/public-key-authenticated-encryption-and-why-you-want-it-part-ii/
https://neilmadden.blog/2018/12/14/public-key-authenticated-encryption-and-why-you-want-it-part-iii/
and
https://neilmadden.blog/2016/09/13/critical-thinking-for-software-engineers

Phishing-resistant two-factor authentication (2FA) devices that help protect high-value users
Works with popular devices, browsers, and a growing set of apps that support FIDO standards
Built with a hardware chip (with firmware engineered by Google) to verify integrity of the key
Sold on https://store.google.com/product/titan_security_key?hl=de for €35

Need to encode, transmit, or store encrypted or signed data? saltpack is a streamlined, modern solution, designed with simplicity in mind. It is easy to implement & integrate. We've made few crypto decisions and instead leave almost all of the heavy lifting to the NaCl library.

saltpack is a binary message format, encoded using the MessagePack format. Messages are broken up into reasonable (1MB) chunks, over which regular NaCl operations are performed. We have taken pains to address many of the shortcomings of current message formats: (1) only authenticated data is output; (2) repudiable authentication is used wherever possible; (3) chunks cannot be reordered or combined with other transmissions; (4) the public keys of senders and recipients can be hidden; and (5) message truncation is detectable.

Implementations in Go and Python are available at https://saltpack.org/implementations  The format is used by https://keybase.io/

ITL BULLETIN FOR FEBRUARY 2015
NIST SPECIAL PUBLICATION 800-88 REVISION 1,
GUIDELINES FOR MEDIA SANITIZATION
http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-88r1.pdf

Bitmessage is a P2P communications protocol used to send encrypted messages to another person or to many subscribers. It is decentralized and trustless, meaning that you need-not inherently trust any entities like root certificate authorities. It uses strong authentication which means that the sender of a message cannot be spoofed, and it aims to hide "non-content" data, like the sender and receiver of messages, from passive eavesdroppers like those running warrantless wiretapping programs. If Bitmessage is completely new to you, you may wish to start by reading the whitepaper https://bitmessage.org/bitmessage.pdf

Not sure how up to date it is, version 0.6.1 is dated 2016-08-21, the latest one  0.6.3.2 was released 2018-02-14
https://github.com/Bitmessage/PyBitmessage/releases/

According to https://www.reddit.com/r/bitmessage/comments/cjxk9s/current_status_of_pybitmessage/ (2019-07-30) development is on-going.
This can also be seen on github, e.g. https://github.com/Bitmessage/PyBitmessage/issues/1712#issuecomment-830636842
One of the difficulties seems to be the transition from Python2 to Python3.

Uses proof-of-work.

Found on https://karl-voit.at/2014/04/10/bitmessage/