The simplest way to understand encryption, is to think of a decoder wheel. One character becomes another, so the output on the other side of the function becomes garbled and cannot be read, unless we have our own wheel. Modern encryption though, is some more complex than that, because simple decoder wheels can be broken fairly easily, and you need to share the same decoder wheel on both sides. If you do so, nothing prevents someone having a decoder wheel to encode a message just like you would, which would allow any of the recipients to fake messages like originating from you.
Modern encryption uses “non invertible” or asymmetric functions, and also introduces “private” and “public” keys. What this basically means, is that there is only one way to use the system. The private key encrypts, and the public one is used to decrypt. It doesn’t mean that the public key cannot be used to encrypt, but it will look different.
With this nifty trick, not only is our message private, but we can also know for sure who is generating a message.
Then we put it on a chain, and we have the equivalent of sealing it in amber forever.
Secrets become truth.