About this app

CryptxHDx (for tablets) is a convenient, simple-to-use proprietary text encryption platform that utilizes its own SQLite database for data archiving.

Data ciphering logic uses AES, the Advanced Encryption Standard, which is a 128-bit symmetric-key text encryption specification that was approved by the U.S. National Institute of Standards and Technology in 2002, and is used by the U.S. government and other institutions worldwide.

App features:
* 128-bit AES encryption using:
- SecureRandom() with 'SHA1PRNG' salt
- SecretKeyFactory() with 'PBEWithSHAAnd128BitAES-CBC-BC'
- Cipher() with 'AES/CBC/PKCS7Padding'
* User-supplied cipher key(s) up to 12 characters long
* No-limit recursive encryption
* Any character set (language) can be encrypted*
* No app restrictions to data manipulation size
* SQLite database for archiving (with search and sort)
* 'Share' and Clipboard-paste for forwarding
* Scrollable real-time 'on screen' Event Log
* Built-in Help file
* Note: This free version permits only 5 'folders' in the database

By using other Android apps, your encrypted data can be posted on the Web or transmitted to other Android devices around the globe. The destination receivers would use their own CryptxHDx app (see note below) and your previously-disclosed encryption key(s) to decipher the forwarded message.

If you don't distribute your cipher texts, then you can save them in a SQLite database on your own Android tablet. The information is stored in 'folders' where it can later be individually retrieved and decrypted to reveal your old confidential notes. (A maximum of 5 'folders' are permitted with this free app.)

NOTES: If you discover you need more than 5 'folders', download the app: CryptxHD. The tablet-targeted CryptxHD and CryptxHDx apps, and the smartphone-targeted Cryptxphile and Crypt2phile apps may all be used to decrypt any AES+ data file. Be aware that Triple-DES strings can not be decrypted by the AES algorithm, and vice versa.

Caveat: Mix together enough mathematicians, cryptographers, CPU's, and research time in a computer lab and you'll discover any encrypted text on planet Earth can be deciphered. Therefore, don't expect to find an "uncrackability" guarantee with this app! But by combining an off-the-shelf encryption algorithm with multiple private keys and unlimited recursion, hackers will be repulsed from even attempting to brute-force-attack your ciphered texts.

* Note1: the Unicode characters x2500-x256C are reserved for data encoding!

Note2: This app uses the "menu" button...which is likely missing on the newer models of tablets and smartphones! Check which your device manufacturer (via a Google search) to find out how this button is now simulated.

New features

Make the app's cipher logic compatible with Android operating system Lollipop (v 5).