Vernam Cipher

Vernam Cipher

By Jeff Isaak

Vernam CipherVernam CipherVernam CipherVernam Cipher

Using this app, you can create and share secret keys that you can then use to encrypt and decrypt messages utilizing the Vernam Cipher. This implementation acts as a one time pad because it discards the a half of the key used to encrypt/decrypt messages.

Source code is available at

Changelog (from v1.1 onwards):

Version 1.10

- Upgraded Android SDK and Gradle versions.

- Updated the 'about' text.

Version 1.9:

- Fixed a couple of bugs that were causing crashes

Version 1.8

- Added a message to the consumer indicating their password protected secret keys are broken (terribly sorry everyone)

Version 1.7

- Fixed a bug that was inflicting secret key importing to fail.

- Fixed a bug that was causing password-protected secret keys to fail.

Version 1.6

- Fixed a bug that was causing the variety of bytes remaining in a password-protected secret key to be misrepresented

- Added the display of the cipher textual content when decrypting a message.

- Added the power to view a secret key (long press on a secret key within the record, then select 'View secret key').

Verison 1.5

- Fixed a bug that caused the app to crash when decryption was attempted with no secret keys generated

Version 1.4

- Fixed a bug that triggered the app to crash on startup for model new installations

Version 1.3

- Added ability to share encrypted messages as text or as a file - this opens up new sharing options

- Miscellaneous code cleanup

- Added a link to my donation page (yes, shameless self-promotion)

Version 1.2

- Fixed an error connecting to

Version 1.1

- Fixed a somewhat crippling Nougat bug

- Expanded the error message when knowledge fetching fails