When the PHP server interacts with the client and provides an open API, it is usually necessary to encrypt the sensitive part of the API data transmission. At this time, RSA asymmetric encryption can come in handy. Here is an example to illustrate how to use PHP. Realize data encryption and decryption

1. The first step in encryption and decryption is to generate a public key and private key pair. The content encrypted by the private key can be decrypted by the public key (and vice versa)

Download the open source RSA key Generate the tool openssl (usually Linux systems come with this program), unzip it to a separate folder, enter the bin directory, and execute the following command:

openssl genrsa -out rsa_private_key.pem 1024
openssl pkcs8 -topk8 -inform PEM -in rsa_private_key.pem -outform PEM -nocrypt -out private_key.pem
openssl rsa -in rsa_private_key.pem -pubout -out rsa_public_key.pem

The first command generates the original RSA private key file rsa_private_key.pem, the second The first command converts the original RSA private key to pkcs8 format, and the third command generates the RSA public key rsa_public_key.pem
From the above, it can be seen that the corresponding public key can be generated through the private key, so we use the private key private_key.pem on the server side. The public key is issued to front-ends such as android and ios

2. Use the generated public key and private key in php for encryption and decryption, and directly upload the code

<?php
$private_key = &#39;-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----&#39;;
 
$public_key = &#39;-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC3//sR2tXw0wrC2DySx8vNGlqt
3Y7ldU9+LBLI6e1KS5lfc5jlTGF7KBTSkCHBM3ouEHWqp1ZJ85iJe59aF5gIB2kl
Bd6h4wrbbHA2XE1sq21ykja/Gqx7/IRia3zQfxGv/qEkyGOx+XALVoOlZqDwh76o
2n1vP1D+tD3amHsK7QIDAQAB
-----END PUBLIC KEY-----&#39;;
 
//echo $private_key;
$pi_key =  openssl_pkey_get_private($private_key);//這個函數(shù)可用來判斷私鑰是否是可用的，可用返回資源id Resource id
$pu_key = openssl_pkey_get_public($public_key);//這個函數(shù)可用來判斷公鑰是否是可用的
print_r($pi_key);echo "\n";
print_r($pu_key);echo "\n";
 
 
$data = "aassssasssddd";//原始數(shù)據(jù)
$encrypted = ""; 
$decrypted = ""; 
 
echo "source data:",$data,"\n";
 
echo "private key encrypt:\n";
 
openssl_private_encrypt($data,$encrypted,$pi_key);//私鑰加密
$encrypted = base64_encode($encrypted);//加密后的內(nèi)容通常含有特殊字符，需要編碼轉(zhuǎn)換下，在網(wǎng)絡(luò)間通過url傳輸時要注意base64編碼是否是url安全的
echo $encrypted,"\n";
 
echo "public key decrypt:\n";
 
openssl_public_decrypt(base64_decode($encrypted),$decrypted,$pu_key);//私鑰加密的內(nèi)容通過公鑰可用解密出來
echo $decrypted,"\n";
 
echo "---------------------------------------\n";
echo "public key encrypt:\n";
 
openssl_public_encrypt($data,$encrypted,$pu_key);//公鑰加密
$encrypted = base64_encode($encrypted);
echo $encrypted,"\n";
 
echo "private key decrypt:\n";
openssl_private_decrypt(base64_decode($encrypted),$decrypted,$pi_key);//私鑰解密
echo $decrypted,"\n";