Information
It was found that the first few bytes of the keystream in RC4 were strongly non-random and leaked information about the key. This is countered here in RC4 Drop by dropping the inital part of the key stream and increasing security.
How to use:
Firstly, input a key. This will be used in the algorithm to encrypt your plaintext. Alternatively, the generate key button will do so for you.
Then, input some plaintext; what you want to encrypt. An output will appear in the bottom boxes with the base64 and hexadecimal versions of your ciphertext along with execution time.
Conversely, to decrypt, simply add the base64 ciphertext into the top input box along with key to decrypt with.