php服務(wù)端與客戶端交互、提供開放api時(shí)，通常需要對(duì)敏感的部分api數(shù)據(jù)傳輸進(jìn)行數(shù)據(jù)加密，這時(shí)候rsa非對(duì)稱加密就能派上用處了，下面通過一個(gè)例子來說明如何用php來實(shí)現(xiàn)數(shù)據(jù)的加密解密

1、加密解密的第一步是生成公鑰、私鑰對(duì)，私鑰加密的內(nèi)容能通過公鑰解密（反過來亦可以）

下載開源RSA密鑰生成工具openssl（通常Linux系統(tǒng)都自帶該程序），解壓縮至獨(dú)立的文件夾，進(jìn)入其中的bin目錄，執(zhí)行以下命令：

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

第一條命令生成原始 RSA私鑰文件 rsa_private_key.pem，第二條命令將原始 RSA私鑰轉(zhuǎn)換為 pkcs8格式，第三條生成RSA公鑰 rsa_public_key.pem
從上面看出通過私鑰能生成對(duì)應(yīng)的公鑰，因此我們將私鑰private_key.pem用在服務(wù)器端，公鑰發(fā)放給android跟ios等前端

2、php中用生成的公鑰、私鑰進(jìn)行加密解密，直接上代碼

<?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(gè)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(gè)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(shí)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";