e-Nigma
Purpose

The e-Nigma is to protect content files (in particular, documents classified against access by third parties). The protection is realized through encryption the contents of a file with 128 bit key of RC4 algorithm, produced with the password entered by the user. In practical terms for the lack of familiarity with the 128 bit key does not allow know the content previously encrypted file. RC4 is a widely used algorithm symmetric key encryption developed by RSA Data Security Inc.. The algorithm uses a key to encrypt and decrypt information and requires a relatively small surcharge calculation.

Requirements

Microsoft Windows 95/98, Windows NT and higher derivatives (Windows 2000, XP, Vista). Internet Explorer 5.5 or higher with 128 bit encryption strength or higher, Windows Mobile 5.0. or higher.

Functionality

The e-Nigma is integrated in Windows Explorer shell and the email program. Setting the mouse cursor to any file and click the right mouse button causes display the context menu with the command: Encrypt for files with an extension other than ".enigma" or Decrypt - for files with the extension ".enigma".

Rys. 5. Pocket PC version.

Rys. 6. Pocket PC version - integration with explorer.

Fig. 1. Windows Explorer context menu.

Fig. 2. Integration with mail program.

Fig. 3. File decryption.

Fig. 4. View of program main window.

Description

User selects a file to encrypt or deciphering. Enter the password confirmation. The password is hashing with MD5 algorithm. Next from the output which obtained from hash programm generate symmetric key with a length of 128 bits or 40 bits - set by the user. At the end of the content of the file is encrypted by chunks using symmetric key RC4 algorithm. The resulting file is the same size as the source. The source file after successful encryption is deleted - see deleting the source file. To restore the contents of an encrypted file you need to know the password used for encryption. Ignorance of terms - Prevents the reproduction of the content of the file. Passwords are not stored in the system.

Strength of encryption

An important issue for safety length of encrypted information is used keys (eg 128 bits). The keys are longer, the harder it is to decrypt the information. It is widely agreed that:

  • for asymmetric keys: 512 - is too low, 768 - a relatively safe, 1024 - Strong safety.
  • for symmetric keys : 40 - is too little, 56 - a relatively safely, 128 - strong safety.

Violations of the key method of brute force (check the possible keys in order):

  • 40 bit key, took 3 hours the network computers.
  • breaking 56 bit key (in the RC5 algorithm) took 250 days in one of the projects distributed.net . The experiment was carried out by a network of computers, whose performance 26 tysięcom was equivalent to a Pentium-class computers 200.
  • breaking 128 bit key would take 1 trillion x 1 trillion years (with a single supercomputer).
Technical Data

Encryption Algorithm: RC4.
Key Length: 128 bits.
Delete the original file: once blurring the public content.
Reducing the length of the file: no limits.

Documentation.

Platform WIN32 PC:
e-Nigma setup (version: 1.0.4, size: 700 KB).
Please send direct comments to the following address: artur.majuch @ e-msoft.com

Platform Windows Mobile 5.0:
e-Nigma setup (version: 1.0.4, size: 100 KB).
See movie

In preparation

The principles of distribution.

Trademarks

Microsoft, Windows - are registered trademarks of Microsoft Corporation.

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