php rsa加密解密实例

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

1. $private_key = '-----BEGIN RSA PRIVATE KEY-----  
2. MIICXQIBAAKBgQC3//sR2tXw0wrC2DySx8vNGlqt3Y7ldU9+LBLI6e1KS5lfc5jl  
3. TGF7KBTSkCHBM3ouEHWqp1ZJ85iJe59aF5gIB2klBd6h4wrbbHA2XE1sq21ykja/  
4. Gqx7/IRia3zQfxGv/qEkyGOx+XALVoOlZqDwh76o2n1vP1D+tD3amHsK7QIDAQAB  
5. AoGBAKH14bMitESqD4PYwODWmy7rrrvyFPEnJJTECLjvKB7IkrVxVDkp1XiJnGKH  
6. 2h5syHQ5qslPSGYJ1M/XkDnGINwaLVHVD3BoKKgKg1bZn7ao5pXT+herqxaVwWs6  
7. ga63yVSIC8jcODxiuvxJnUMQRLaqoF6aUb/2VWc2T5MDmxLhAkEA3pwGpvXgLiWL  
8. 3h7QLYZLrLrbFRuRN4CYl4UYaAKokkAvZly04Glle8ycgOc2DzL4eiL4l/+x/gaq  
9. deJU/cHLRQJBANOZY0mEoVkwhU4bScSdnfM6usQowYBEwHYYh/OTv1a3SqcCE1f+  
10. qbAclCqeNiHajCcDmgYJ53LfIgyv0wCS54kCQAXaPkaHclRkQlAdqUV5IWYyJ25f  
11. oiq+Y8SgCCs73qixrU1YpJy9yKA/meG9smsl4Oh9IOIGI+zUygh9YdSmEq0CQQC2  
12. 4G3IP2G3lNDRdZIm5NZ7PfnmyRabxk/UgVUWdk47IwTZHFkdhxKfC8QepUhBsAHL  
13. QjifGXY4eJKUBm3FpDGJAkAFwUxYssiJjvrHwnHFbg0rFkvvY63OSmnRxiL4X6EY  
14. yI9lblCsyfpl25l7l5zmJrAHn45zAiOoBrWqpM5edu7c  
15. -----END RSA PRIVATE KEY-----';  
16.   
17. $public_key = '-----BEGIN PUBLIC KEY-----  
18. MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC3//sR2tXw0wrC2DySx8vNGlqt  
19. 3Y7ldU9+LBLI6e1KS5lfc5jlTGF7KBTSkCHBM3ouEHWqp1ZJ85iJe59aF5gIB2kl  
20. Bd6h4wrbbHA2XE1sq21ykja/Gqx7/IRia3zQfxGv/qEkyGOx+XALVoOlZqDwh76o  
21. 2n1vP1D+tD3amHsK7QIDAQAB  
22. -----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($pi_key);echo "\n"; echo "
";
print_r($pu_key);echo "\n"; echo "
";
echo "

$data='php ras加密算法';
$encrypted = "";
$decrypted = "";

echo "加密的源数据:".$data."\n"; echo "
";
echo "private key encrypt:\n"; echo "
";
openssl_private_encrypt($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 '私钥加密后：'.$encrypted."\n"; echo "
";echo "
";

echo "public key decrypt:\n"; echo "
";
openssl_public_decrypt(base64_decode($encrypted),$decrypted,$pu_key);//私钥加密的内容通过公钥可用解密出来
echo '公钥解密后：'.$decrypted."\n"; echo "
";
echo "

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

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