Cryptography (not cryptology, which contains cryptography and cryptanalysis) is a study of encryption from a mathematical point of view. It is also used for secret communication, which allows the world to see an encrypted message in case someone is listening, and does not let them know the real word. Only the intended recipient can read it. As you mentioned, you can also “register” things using a similar scheme, but where “pre-decrypt” (my term) is something, and other people who link your cryptographic key can show that you’ve signed something.
So, cryptography is used almost exclusively in security areas. You can only restrict those authorized to access secret data. This is useful for sending messages, ensuring that only paid customers can install the software and be responsible (at least trying to prevent people from “joking” with their phone.
It can also provide some security in other ways. Some “dark networks,” especially Freenet, do not censor information. Each user stores the data on their computer, so their removal will not eliminate data from the network. After downloading the report, it can be almost impossible to erase it. In the case of illegal content, you can place it on a computer without knowledge. However, since it is encrypted, the judge should not be guilty of keeping the data on the computer because not only is it impossible to prove that your computer is hosting illegal content, but even if it can, it can. Do not access unless you intentionally try to decrypt it through other illicit routes.
With Bitcoin, you can also find cryptographic applications in:
Tahoe-LAFS (and other encrypted file storage systems)
PGP / GPG (plain text encryption so you can send emails to people without other people reading the message)
Finally, I will say that unique passwords can be a growing trend. I have a keychain that, to connect to the program, every time I need a new password. Only 64,000 random passwords will be verified as “I am,” so the attacker will not be able to access the passwords, but will not be able to steal the password that he uses and reuses. Once applied, it can no longer be used.
Uses of Cryptography
The crux point of what you have learned so far is that cryptography is the art of storing and writing information in such a way that it only reveals itself to those who need to see it. Hide from everyone else. Before the information age, cryptography was only used to guarantee the secrecy of the information. Encryption has been used to ensure the confidentiality of spy communications, military leaders, and diplomats. Egyptian hieroglyphics, scythe passwords used by Spanish Spartans, plaster and various physical auxiliary devices were used throughout history through modern times. These devices underwent other changes when computers and electronic devices appeared, which contributed significantly to cryptanalysis.