Encrypted communication in PHP

With the popularization of network communications, people are paying more and more attention to information security issues, especially during the data transmission process between the web server and the client. In order to prevent security issues such as theft and tampering of sensitive information, encryption technology is needed to achieve secure transmission of data. As a popular web programming language, PHP supports a variety of encryption algorithms. This article will give a brief introduction to encrypted communication in PHP.

1. Overview of Encryption Algorithm

Encryption algorithm is a process of converting plaintext into ciphertext through certain rules or transformations. In the encryption algorithm, the plaintext is the original, readable data, while the ciphertext is the unreadable data after encryption. Except that the ciphertext is more secure, the rest is the same as the plaintext, and the ciphertext can be transmitted and stored more securely on the network. Common encryption algorithms include DES, AES, RSA, etc.

2. Encrypted communication in PHP

In the security system of PHP, different functions can be used to implement encrypted communication. We can encrypt the data on the server side and then perform it on the client side. Processing, here are several encryption functions commonly used in PHP:

1. md5 algorithm: a commonly used hash algorithm, which can encrypt plaintext into 128-bit ciphertext and is irreversible.
2. sha1 algorithm: Another commonly used hash algorithm, it can encrypt plaintext into 160-bit ciphertext, which is also irreversible.
3. base64 function: This function can convert binary data into ASCII readable characters and is used to send non-text data.
4. openssl_encrypt/openssl_decrypt function: These two functions can use the openssl library to encrypt and decrypt data, supporting multiple encryption algorithms (such as DES, AES, RSA, etc.) and encryption modes (such as ECB, CBC, etc.) .

We can choose the appropriate encryption algorithm for processing according to our needs to ensure the security of the data. We can also use the SSL secure socket layer protocol during the data transmission process to transmit data through https. SSL Provides a method of securely transmitting data like in a safe, while ensuring that the data stored and transmitted is encrypted and digitally signed.

3. Implementation of encrypted communication

In order to achieve encrypted communication, we need to consider the following aspects: data encryption, data decryption, key management and security inspection. The following code takes the OpenSSL algorithm as an example to briefly demonstrate how to use HTTPS for encrypted communication in PHP:

1. Generate certificate:

// 生成证书：
openssl req -new -x509 -days 365 -nodes -out server.crt -keyout server.key

2. PHP code implementation ：

// HTTPS通讯
$timeout = 5;
$url = "https://localhost/test.php";
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
//设置证书
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);//跳过证书验证
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, true);//检查证书中是否设置域名,初始化操作
curl_setopt($ch, CURLOPT_SSLCERTTYPE, 'PEM');//设置证书类型
curl_setopt($ch, CURLOPT_SSLCERT, 'server.crt');//设置证书文件
curl_setopt($ch, CURLOPT_SSLKEYTYPE, 'PEM');//设置证书类型，需要与上面的证书格式一样
curl_setopt($ch, CURLOPT_SSLKEY, 'server.key');//设置证书文件，需要与上面的证书格式一样
//提交参数
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, 'name=Lily&age=18');
$result = curl_exec($ch);
curl_close($ch);
if ($result) {
    echo $result;
}

Encrypted communication is one of the effective measures to ensure network security. We can achieve data confidentiality, integrity and authentication by selecting appropriate encryption algorithms and encryption modes during data transmission. . In PHP, we can choose appropriate encryption functions according to different needs, build secure web applications, and provide users with secure services.

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