Comparison and selection of PHP encryption algorithm and hash algorithm

Comparison and Selection of PHP Encryption Algorithms and Hash Algorithms

Overview
When performing data protection, PHP provides many encryption algorithms and hash algorithms to Ensure data security. This article will compare several common encryption algorithms and hashing algorithms, and discuss how to choose and use them in actual projects.

1. Encryption algorithm

1. Symmetric encryption algorithm
   Symmetric encryption algorithm uses the same key for encryption and decryption. In PHP, the most commonly used symmetric encryption algorithm is AES (Advanced Encryption Standard).

Sample code:

$plaintext = "Hello, World!";
$key = "This is a secret key.";
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length("aes-256-cbc"));

$ciphertext = openssl_encrypt($plaintext, "aes-256-cbc", $key, 0, $iv);

$deciphertext = openssl_decrypt($ciphertext, "aes-256-cbc", $key, 0, $iv);

2. Asymmetric encryption algorithm
   Asymmetric encryption algorithm uses a pair of keys, the public key is used for encryption, and the private key is used for decryption . In PHP, the most commonly used asymmetric encryption algorithm is RSA.

Sample code:

$plaintext = "Hello, World!";
openssl_public_encrypt($plaintext, $ciphertext, $publicKey);
openssl_private_decrypt($ciphertext, $deciphertext, $privateKey);

2. Hash algorithm

The hash algorithm is an algorithm that maps data of any length to a fixed-length digest. The hashing algorithm is one-way, that is, the original data cannot be deduced from the digest.

1. MD5
   MD5 is a widely used hash algorithm, but due to its insufficient security, it is not recommended for storing sensitive information such as passwords.

Sample code:

$plaintext = "Hello, World!";
$hash = md5($plaintext);

2. SHA
   SHA (Secure Hash Algorithm) is the collective name for a series of hash algorithms, including SHA-1, SHA-256, SHA-512 etc. SHA-1 has been deprecated in some applications with higher security requirements, and it is recommended to use the more powerful SHA-256 or SHA-512.

Sample code:

$plaintext = "Hello, World!";
$hash = hash("sha256", $plaintext);

3. Comparison and selection

1. Security
   When choosing encryption algorithms and hashing algorithms, the primary consideration The best is its safety. The symmetric encryption algorithm AES and the asymmetric encryption algorithm RSA are currently widely recognized and used algorithms, and have high security. MD5 has been proven to be flawed in terms of security and is no longer recommended.
2. Performance
   Symmetric encryption algorithms have higher performance than asymmetric encryption algorithms. AES is a fast symmetric encryption algorithm suitable for encryption and decryption of large amounts of data. Due to its complexity, RSA has lower performance and is suitable for encryption and decryption of small amounts of data.
3. Purpose
   Symmetric encryption algorithms are suitable for encryption during data transmission and storage, while asymmetric encryption algorithms are suitable for scenarios such as digital signatures and key exchanges. Hashing algorithms are suitable for verifying data integrity and searching data faster.

In summary, for most application scenarios, it is recommended to choose AES as the encryption algorithm and SHA-256 or SHA-512 as the hash algorithm. When choosing the key length, you should choose 256 bits or 512 bits depending on your security needs.

Conclusion
In PHP, the security and integrity of data can be effectively protected through encryption algorithms and hash algorithms. When selecting an algorithm, safety, performance, and usage should be considered comprehensively, and used flexibly in actual projects.

Reference source:

1. PHP Manual: https://www.php.net/manual/en/
2. OWASP Cryptographic Storage Cheat Sheet: https:/ /cheatsheetseries.owasp.org/cheatsheets/Cryptographic_Storage_Cheat_Sheet.html

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