Cipher is a symbol compiled according to a specific law, which is used to transform the information of both parties in communication. In other words, a password is a sequence of symbols that hides the real content. It is to change the information expressed by an open and standard information code into an information code that can't be read by other people except the communication parties through a transformation method. This unique information code is a password. ?
Cryptography is a science with a long history. Ciphers were used to transmit secret messages in the war between ancient Greece and the Persian Empire. In modern and modern wars, the transmission of information and the command of war are inseparable from passwords, and so is the diplomatic struggle. Passwords are generally used for confidentiality in information communication transmission and storage.
With the development of computer and information technology, the development of cryptographic technology is also very rapid, and its application fields are constantly expanding. Passwords are not only used for information encryption, but also for data information signature and security authentication. In this way, the application of cryptography is no longer limited to serving military and diplomatic struggles, but also widely used in social and economic activities.
Nowadays, there has been a trend of socialization and personalization of password application in the world. For example, cryptographic technology can be applied to e-commerce to identify the identities and commercial credits of both parties in online transactions and prevent "hackers" and fraud in online e-commerce.
When it is applied to VAT invoices, it can prevent counterfeiting and tampering, put an end to all kinds of acts of stealing, leaking, escaping and cheating the state tax by using VAT invoices, and greatly facilitate tax inspection; When it is applied to the identification of bank checks, it can greatly reduce the financial crime of using fake checks for financial fraud; When applied to personal mobile communication, it greatly enhances the confidentiality of communication information and so on.
According to Reuters, a batch of documents declassified by the British Security Service showed the work of British intelligence services to the world for the first time. Deciphering the "password in the skirt" is one of the famous ones.