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 hears it and does not let them know the real word. Only the recipient can read it. As you mentioned, you can also “register” things using a similar scheme, but when there is something “decrypt” (my term) and other people linking your cryptographic key can show that you have signed something.
Therefore, 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 paying customers can install the software and be responsible for it (at least try to prevent people from making “jokes” with the 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 deleting it will not delete the data from the network. After downloading the report, it may be almost impossible to delete it. In the case of illegal content, you can place it on a computer without your knowledge. However, since it is encrypted, the judge should not be guilty of keeping the data on the computer, as not only is it impossible to prove that your computer hosts illegal content, but it can even. Do not access it unless you intentionally try to decrypt it by other illicit routes.
With Bitcoin, you can also find cryptographic applications at:
Tahoe-LAFS (and other encrypted file storage systems)
PGP / GPG (plain text encryption so you can send emails to people without others 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 such as “I am” will be verified, so the attacker will not be able to access the passwords, but will not be able to steal the password they use and reuse. Once applied, it will no longer be usable.
Uses of cryptography
The crucial point of what you’ve learned so far is that cryptography is the art of storing and writing information in a way that is only revealed to those who need to see it. Hide from everyone else. Before the information age, cryptography was only used to ensure the secrecy of information. Encryption has been used to ensure the confidentiality of spy communications, military leaders and diplomats. Egyptian hieroglyphics, sickle passwords used by Spanish Spartans, chalk, 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.