The specific applications of cryptography are as follows:

Definition of cryptography

Cryptography is the technical science that studies the preparation and deciphering of codes. The study of the objective laws of password changes, which is applied to compiling codes to keep communication secrets, is called cryptography; the application to deciphering codes to obtain communication intelligence is called deciphering, and is generally called cryptography.

Password deciphering

Code deciphering is gradually produced and developed with the use of passwords. In 1412, the encyclopedia compiled by the Persian Kalakachandi contained methods for deciphering simple substitution ciphers. By the end of the 16th century, some European countries had full-time codebreakers to decipher intercepted secret messages.

Cryptocracking technology has made considerable progress. "Cryptozoology and Decryption Techniques" written by the Prussian Kassky in 1863, and "Military Cryptozoology" written by the Frenchman Kerkhov in 1883 have made some discussions and discussions on the theory and methods of cryptography. Discuss. In 1949, American Shannon published the article "Communication Theory of Secret Systems", which applied the principles of information theory to analyze some basic issues in cryptography.

Classical cryptography

Before modern times, cryptography only considered the confidentiality of information: how to convert understandable information into incomprehensible information, and make it easier to understand. The person with the secret information can reply in reverse, but the interceptor or eavesdropper who lacks the secret information cannot decipher it.

In recent decades, this field has expanded to include various technologies such as identity authentication (or authentication), information integrity checking, digital signatures, interactive proofs, and secure multi-party computation.