From RSA Security's website:
"RC4 is a stream cipher designed by Rivest for RSA Data Security (now RSA Security). It is a variable key-size stream cipher with byte-oriented operations. The algorithm is based on the use of a random permutation. Analysis shows that the period of the cipher is overwhelmingly likely to be greater than 10^100. Eight to sixteen machine operations are required per output byte, and the cipher can be expected to run very quickly in software. Independent analysts have scrutinized the algorithm and it is considered secure."

This implementation encodes the byte stream to be encrypted "in-place".

Example:
Byte[] Key = new Byte[5] { 12, 34, 22, 12, 32 };
Byte[] B = new Byte[10] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
// Examine B array before and after this next call.
RC4(ref B, Key);
// Examine B array before and after this next call.
RC4(ref B, Key);

This litle snippet shows how to store passwords and then check inputed passwords if they are correct.

(In this snippet we use som pseduo code for the database connection).

This snippet generates a secure hash string using VB.NET

Generates an 88 character secure hash string for the passed in strings.

This could be used for any type of simple hash checking. It could also be used to store a "password" that had to be verified. This code is completely managed.

MySQL 5.x Stored Routines, PHP Session Values, a little CSS oh my! Complex to set up but easy to impliment. Geared toward security, simplicity (of use) and convenience.