Knowledgebase

Encryption and decryption are the most commonly used data conversion methods in communication. The basic process of encryption is to apply encryption algorithms and keys to encrypt plaintext (unencrypted original text), convert it into ciphertext, and send it; The basic process of decryption is to receive the ciphertext, apply the corresponding algorithm and the same key to decrypt the ciphertext, and convert it into plaintext;
The two parties involved in encryption and decryption encrypt or decrypt based on prior basic agreements (including encryption algorithms) and the given key, while a third party is unaware of the agreement. Even if they know the ciphertext and key, it is difficult to decrypt and understand the content of the communication. Below, we will introduce the most common encryption and decryption methods.
1. Base64 bit encryption (capable of encryption and decryption)
The simplest encryption method, without a key, allows others to directly decrypt your ciphertext. It can only be used for deception and is generally not used alone because it is not very useful. It can be mixed with other encryption methods as an external packaging.
2. MD5 encryption (irreversible encryption)
The full name of MD5 is Message Digest Algorithm 5. 128 bit length. Currently, MD5 is an irreversible algorithm. It has high security. It can encrypt any string into a unique fixed length code. (Tip: Why is the MD5 encryption algorithm irreversible? In theory, if there is an encryption method, there will be a decryption method. Because MD5 encryption is a lossy encryption method, for example, if a piece of data is' 123 ', when I encrypt it, I directly treat 1 and 3 as' a', and after encryption, it becomes' a2a '. Therefore, when decrypting, there are four combinations of' 323 '', '121', '123', and '321'. With a large amount of data, the original data cannot be found. Of course, the encrypted ciphertext in this way does not need to be decrypted, and the original ciphertext can be sent directly when needed. It's just that I can't see the original content of the ciphertext.)
3. SHA1 encryption (irreversible encryption)
The full name of SHA1 is Secure Hash Algorithm. SHA1 is based on MD5, and the encrypted data has a longer length. It generates a hash value of 160 bits for inputs with a length less than 264. 32 bits more than MD5. Therefore, SHA1 is more secure than MD5, but its computation speed is slower than MD5. The usage method is actually the same as MD5.
4. AES encryption (requires a key to decrypt)
AES encryption is symmetric key encryption, and both encryption and decryption use the same decryption rule. The AES encryption process operates on a 4 × 4 byte matrix, also known as the "state". Because the key and encryption block need to be iterated, replaced, and combined multiple times on the matrix, there are certain requirements for encryption speed and the number of bytes of the key. The minimum supported AES key length is 128, 192, and 256, and the encryption block group length is 128 bits. This encryption mode has a biggest weakness: the first party must inform the second party of the encryption rules, otherwise it cannot be decrypted. Saving and transmitting keys has become the most headache inducing issue.
5. RSA encryption (public key encryption, private key decryption)
It is currently the most important encryption algorithm! The cornerstone of computer communication security ensures that encrypted data will not be cracked. You can imagine the consequences of credit card transactions being hacked. Communication between Party A and Party B. Party B generates a public key and a private key, and Party A obtains the public key and encrypts the information (the public key is public and can be obtained by anyone). Party A encrypts the information using the public key, and only the private key can crack the encrypted information. Therefore, as long as the private key is not leaked, the security of the information can be guaranteed.
The above is the complete content of the "Introduction to Several Common Encryption and Decryption Methods" shared for everyone. If users encounter problems that cannot be solved, they can seek help through the customer service of the DNSHE official website. For website users who choose DNSHE SSL certificates, DNSHE can provide free one-on-one SSL certificate technology deployment support, eliminating worries