Modern encryption is based on digital “keys”. OpenKeychain stores and manages your keys, and those of the people you communicate with, on your Android. It also helps you find others’ keys online, and interchange keys by touching devices. But its most frequent use is in using those keys to encrypt and decrypt messages.
★ Integration with other Apps:
• K-9 Mail
• and many more…
★ Open Source: OpenKeychain is designed to be trustworthy. It’s Free Software with no secrets; anyone can examine and validate every bit of it (Source code available at https://github.com/open-keychain/open-keychain)
★ Independent Security Audit: The auditing company Cure53 performed an intensive security audit of OpenKeychain. The security experts summarize their final result with "[...] none of the spotted issues were considered to be of a critical severity in terms of security implications. The latter is a significant and impressive result for an app of this complexity and relevance."
★ Permissions: Because OpenKeychain is Free Software, anyone can validate that the permissions are indeed only required for the listed features.
• In-app purchases: Donate to the developers
• Identity: Pre-fill name and email addresses
• Contacts: Connect keys to your contacts (only offline)
• Photos/Media/Files: Import/export keys from SD card
• Camera: Scan QR Codes to add other people's keys
• Others: Internet permission to retrieve keys, NFC permission to use YubiKeys
Starting with Android 6, permissions are requested when required in-app!