Kean's Coder

Kean's Coder is an intuitive and user-friendly application that provides a simple way of encrypting and decrypting text messages in a secure manner.
Fit for scenarios that involve sharing highly sensitive information, Kean's Coder creates a private communication environment that stands little chances of being invaded by prying eyes.
The program is intended for email messages mostly, but can be used in a wider array of situations, such as IM conversations, LAN chat and virtually anywhere you require to carry out an encrypted communication session.
The coding process is based on a user-defined key, which the program can also generate one for you, with the observation that only numeric characters are accepted.
It can also produce a list of keys based on a calendar for one, two, three or six months in case the intended recipient will be out of town, for instance.
Other than this, all that remains to be done is to enter the message and press the ‘Encode’ button, which results in an encrypted sequence of strings that can be exported to a text file or attached directly to an email (works with Outlook only).
Keep in mind that the recipient needs the encryption key you used for the coding of the message in order to decrypt it. Also, the decryption can only be performed with Kean's Coder, so the receiver is required to have the program installed as well.
We were not able to tell what type of algorithm Kean's Coder uses, but considering that the same key is used for both the encryption and the decryption process, it appears to be based on a symmetric-key schema, which is known to be susceptible to some types of attacks.