After Learning a few simple and a few complex encryption algorithms I have come up with one of my own it took a lot of time to figure it out. I wanted to see if any one of you is able to decrypt a message encrypted using it to check security as I am planning to use it in a software of mine for software display.

The following message has been encrypted using a 7 letter key. I want to see if anyone even slightly interested in cryptography is able to decrypt it even if you are not in Exun.

Ciphertext:

ABD4D2D699C7E3D6D083EBE8E594CCC6D9D799B4
D9C7D7DCE2EDD5D884C683B5E8DCE9D1D383DADE
E8D5D8D7C4E0ECE0E3D7CED7DBE8DE94C7CED3DA
DEE2E8C9DDD7A0

Key:
*******

If anyone is able to solve this or if you have any queries please post a message in the comments section.