PHP rsa加密解密使用方法

php服务端与客户端交互、提供开放api时，通常需要对敏感的部分api数据传输进行数据加密，这时候rsa非对称加密就能派上用处了，下面通过一个例子来说明如何用php来实现数据的加密解密

1、加密解密的第一步是生成公钥、私钥对，私钥加密的内容能通过公钥解密（反过来亦可以）

下载开源rsa密钥生成工具openssl（通常linux系统都自带该程序），解压缩至独立的文件夹，进入其中的bin目录，执行以下命令：

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

第一条命令生成原始 rsa私钥文件 rsa_private_key.pem，第二条命令将原始 rsa私钥转换为 pkcs8格式，第三条生成rsa公钥 rsa_public_key.pem
从上面看出通过私钥能生成对应的公钥，因此我们将私钥private_key.pem用在服务器端，公钥发放给android跟ios等前端

2、php中用生成的公钥、私钥进行加密解密，直接上代码

<?php
$private_key = '-----begin rsa private key-----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-----end rsa private key-----';

$public_key = '-----begin public key-----
migfma0gcsqgsib3dqebaquaa4gnadcbiqkbgqc3//sr2txw0wrc2dysx8vnglqt
3y7ldu9+lbli6e1ks5lfc5jltgf7kbtskchbm3ouehwqp1zj85ije59af5gib2kl
bd6h4wrbbha2xe1sq21ykja/gqx7/iria3zqfxgv/qekygox+xalvoolzqdwh76o
2n1vp1d+td3amhsk7qidaqab
-----end public key-----';

//echo $private_key;
$pi_key = openssl_pkey_get_private($private_key);//这个函数可用来判断私钥是否是可用的，可用返回资源id resource id
$pu_key = openssl_pkey_get_public($public_key);//这个函数可用来判断公钥是否是可用的
print_r($pi_key);echo "\n";
print_r($pu_key);echo "\n";


$data = "aassssasssddd";//原始数据
$encrypted = ""; 
$decrypted = ""; 

echo "source data:",$data,"\n";

echo "private key encrypt:\n";

openssl_private_encrypt($data,$encrypted,$pi_key);//私钥加密
$encrypted = base64_encode($encrypted);//加密后的内容通常含有特殊字符，需要编码转换下，在网络间通过url传输时要注意base64编码是否是url安全的
echo $encrypted,"\n";

echo "public key decrypt:\n";

openssl_public_decrypt(base64_decode($encrypted),$decrypted,$pu_key);//私钥加密的内容通过公钥可用解密出来
echo $decrypted,"\n";

echo "---------------------------------------\n";
echo "public key encrypt:\n";

openssl_public_encrypt($data,$encrypted,$pu_key);//公钥加密
$encrypted = base64_encode($encrypted);
echo $encrypted,"\n";

echo "private key decrypt:\n";
openssl_private_decrypt(base64_decode($encrypted),$decrypted,$pi_key);//私钥解密
echo $decrypted,"\n";