NfnxybEz

1- secret_key
2- plain_text 
3     
4- pseudo_key = SHA(plain_text) + secret_key
5- initialization_vector = SHA(plain_text)
6- encrypted_message = SHA(plain_text) + Encrypt_AES-256-cfb(pseudo_key, plain_text) 
7     
8plain_text: Decrypt_AES-256-cfb(SHA_part_of_encrypted_message + secret_key, remaining_of_encrypted_message) 
9     
10- secret_key
11- plain_text 
12     
13- R = randomNumber (e.g. Rand(0000-FFFF))
14- pseudo_key = SHA(plain_text + R) + secret_key
15- initialization_vector = SHA(plain_text + R)
16- encrypted_message = SHA(plain_text + R) + Encrypt_AES-256-cfb(pseudo_key, plain_text) 
17     
18- plain_text: Decrypt_AES-256-cfb(SHA_part_of_encrypted_message + secret_key, remaining_of_encrypted_message), with SHA_part as IV