Autocrypt is described as 'set of guidelines for developers to achieve convenient end-to-end-encryption of e-mails. It specifies how e-mail programs negotiate encryption capabilities using regular e-mails' and is an app in the Security & Privacy category. There are more than 25 alternatives to Autocrypt for a variety of platforms, including Windows, Mac, Linux, Android and OpenPGP. The best alternative is GnuPG, which is both free and Open Source. Other great apps like Autocrypt are GPG4Win (Free, Open Source), AES Crypt (Free, Open Source), Encrypto (Free) and Axcrypt (Freemium).
GnuPG allows to encrypt and sign your data and communication, features a versatile key management system as well as access modules for all kinds of public key directories. GnuPG, also known as GPG, is a command line tool with features for easy integration with other applications.
Gpg4win enables users to securely transport emails and files with the help of encryption and digital signatures. Encryption protects the contents against an unwanted party reading it. Digital signatures make sure that it was not modified and comes from a specific sender.
AES Crypt is an advanced file encryption utility that integrates with the Windows shell or runs from the Linux command prompt to provide a simple, yet powerful, tool for encrypting files using the Advanced Encryption Standard (AES).
Encrypto lets you encrypt files before sending them to friends or coworkers. Just drop a file into Encrypto, set a password, and then send it however you normally would — but this time with added security. It’s free for both Mac and Windows.
Password-encryption of files and folders. The program is written in Java and therefore platform-independent and runs on nearly every system without installation, but requires a Java Runtime Environment - that is already installed in most cases.
It offers an automatic and easy to use solution with end-to-end protection for all written digital communications over the Internet. It have been designed to provide extremely easy and automatic encryption by default for e-mail.