RC4 File Encrypt Decrypt Program

This final RC4 Basics video will discuss File encryption / decryption using RC4. The RC4 algorithm is symmetric ( the encryption and decryption keys are the same ) and thus we can encrypt a file using a secret key and the receiver of the file will decrypt it using the same key. This works because ( A xor B ) xor A = B . What this means is if the same keystream is Xor'ed with the plain text twice, then the text remains unaltered. Thus this provides a way for decrypting the cipher text very easily. In this video we will look at a simple Rc4 file encryptor which takes a key as input and encrypts the file.
Please download this file, before you view the presentation

Enable Javascript or Download Flash Playe if you see this!

Links:

1. RC4 Basics on Wikipedia

2. RSA Basics from RSA Labs

Vivek Ramachandran is a security evangelist and has been working in computer security related fields for the past 7 years. In 2007, Vivek spoke at world renowned conferences Defcon (WEP Cloaking Exposed) and Toorcon (The Caffe Latte Attack). The discovery of the Caffe Latte Attack was covered by CBS5 news, BBC online, Network World etc news agencies.In 2006, Vivek was announced as one of winners of the Microsoft Security Shootout contest held in India among 65,000 participants. He has also been a recipient of a Team Achievement at Cisco Systems for his work on 802.1x and Port Security modules on the Catalyst 6500 switches. Currently he spends all of his time maintaining Security- Freak.Net , SecurityTube.Net and is the founder of an online startup (currently in stealth mode). Vivek, is a Bachelor in Electronics and Communications Engineering from the prestigious Indian Institute of Technology, Guwahati.You can contact him at vivek[at]securitytube.net