Digital signature in Layman's terms

The incredible thing, but all the cryptography consists of three types of cryptographic transmutations only:

• Hash, when you create a fingerprint for something digital.

• Symmetric cryptography, when you have the same key for encryption and description.

• Asymmetric cryptography, when you have one key for encryption and another for decryption; mathematic tells here, that one key cannot be used to encrypt something and then decrypt.

All we have around us is just a creative usage of these three transmutations. A digital signature is not an exception. In fact, it is a pure asymmetric cryptography implementation. It is used to confirm your authorship of something digital. What is inside?

When you use it, first, you create 2 keys. One you keep for yourself (secret), and the other you give to everyone (public). To prove to everyone your authorship, you encrypt your message with your own private secret key that no one knows. No one has it. Only you can use this key. This is the key point here.

If anyone receives your encrypted message, he may try to decrypt it with a key s/he found on Google. Would that help? No. He will get gibberish. S/he may try to guess a key, but that would not help too. The only key in the whole universe that will make from your encrypted message a readable text is a key you published ("the second from your pair", your public key, a key everyone knows is yours). If it is applied and works, meaning a message is understandable now, a recipient may determine authorship. "The first from your pair" is known only to one person, "the second from you pair" is available for everyone and only it can be used to decrypt your message. If it fits, then a message is yours.