php服務(wù)端與客戶端互動、提供開放api時，通常需要對敏感的部分api資料傳輸進行資料加密，這時候rsa非對稱加密就能派上用處了，下面透過一個例子來說明如何用php來實作資料的加密解密

1、加密解密的第一步是產(chǎn)生公鑰、私鑰對，私鑰加密的內(nèi)容能透過公鑰解密（反過來亦可）

下載開源RSA金鑰產(chǎn)生工具openssl（通常Linux系統(tǒng)都會自備該程式），解壓縮至獨立的資料夾，進入其中的bin目錄，執(zhí)行下列指令：

openssl genrsa -out rsa_private_key.pem 1024
openssl pkcsform -top88in 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
up條指令將原始RSA私鑰轉(zhuǎn)換為pkcs8格式，第三條產(chǎn)生RSA公鑰rsa_public_key.pem

從上方看出透過私鑰產(chǎn)生對應(yīng)的公鑰，因此我們將私鑰private_key.pem用在伺服器端，公鑰發(fā)放給android跟ios等前端

2、php中用產(chǎn)生的公鑰、私鑰加密解密，直接上程式碼

<?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";