Tree Substitution Cipher

Generation Algorithm:

1. Generate random tree. Tree nodes contain ID, Neighbours and Data (an integer)
2. Key is root's ID

To encrypt:

1. Write data in nodes in BFS order with sorting by IDs
2. Encrypted is dict where key is ID and value is Node's data

To decrypt:

1. Write data in nodes by ids
2. Read in BFS order with sorting by IDs

For encryption and decryption example see main.py