What are the more common data encryption algorithms?

Comparison of several commonly used data encryption algorithms

Several symmetric encryption algorithms: AES, DES, 3DES

DES is a high-speed packet data encryption technology that divides data into small data blocks of fixed length and then encrypts each data block. 3DES is an encryption algorithm based on DES. By encrypting the same data block three times and using different keys, the strength of the ciphertext is improved. This encryption algorithm is suitable for scenarios where large amounts of data need to be encrypted because it is faster.

Compared with DES and 3DES algorithms, the AES algorithm has higher speed and resource efficiency, and also provides a higher level of security, so it is widely recognized as the next generation encryption standard.

Several asymmetric encryption algorithms: RSA, DSA, ECC

RSA and DSA have similar security and performance, while ECC has significant advantages in processing speed, bandwidth, storage space, etc.

Several linear hashing algorithms (signature algorithms): MD5, SHA1, HMAC

These algorithms only generate a string of irreversible ciphertext, which is used to verify whether the data has been modified during the transmission process. Since the same generation algorithm will only generate a unique ciphertext for the same plaintext, if the ciphertext generated by the same algorithm is different, it proves that the transmission data has been modified. Usually during data transmission, the use of MD5 and SHA1 algorithms requires both parties sending and receiving data to know the key generation algorithm before transmission. The difference is that the HMAC algorithm needs to generate a key. The sender uses this key to digest the data (generates ciphertext). The receiver then uses this key to digest the received data and determines the generated ciphertexts are the same. Therefore, the HMAC algorithm provides higher security and confidentiality.

For the selection of various encryption algorithms:

Due to the complexity of key management in symmetric encryption algorithms, key management directly determines security. Therefore, for small data volumes, consider using asymmetric encryption algorithms.

In the actual operation process, the usual method is to use an asymmetric encryption algorithm to manage the key of a symmetric algorithm, and use a symmetric encryption algorithm to encrypt data. This approach combines the advantages of two types of encryption algorithms, which can not only achieve faster encryption speed, but also facilitate and secure key management.

If the encryption algorithm is selected, how many bits of the key will be used? Generally speaking, the longer the key, the slower it runs. It should be selected according to the security level we actually need. Generally speaking, RSA recommends using 1024-bit numbers, ECC recommends using 160-bit numbers, and AES uses 128-bit numbers. That’s it.

Summarize what encryption algorithm technologies are available in PHP

1. MD5 encryption

string md5 ( string $str [, bool $raw_output = false ] )

2. Crype encryption

string crypt ( string $str [, string $salt ] )

crypt() Returns a hashed string based on the standard UNIX DES algorithm or another alternative algorithm available on the system.

3. Sha1 encryption

string sha1 ( string $str [, bool $raw_output = false ] )

4. URL encryption

string urlencode (string $str)

5. base64

string base64_encode ( string $data )

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