Encrypt and Decrypt a String C#

Well most of the beginner and intermediate programmers like to play with cryptography. This is the part that took me to some trouble in my life. A good encryption and decryption code is easily findable in the Internet and even on The Code Project. Why another? I didn't find a suitable reason behind that one. And when I found some, I mixed them up and this is the result. I just wanted to share the result.
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Awesome teacher

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so awesome wish you all the best

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So nice