RSA非对称加密算法，如果是公钥加密，就得用私钥解密，反过来也一样，私钥加密的就用公钥解密，以下是相关实现函数

<?php

class Rsa
{
    private $PriKye;
    private $PubKey;
    public function __construct()
    {
        $this->PriKye = $this->_getRsaPriKey();
        $this->PubKey = $this->_getRsaPubKey();
    }

    /**
     * RSA私钥加密
     * @param string $private_key 私钥
     * @param string $data 要加密的字符串
     * @return string $encrypted 返回加密后的字符串
     * @author mosishu
     */
    public function privateEncrypt( $data)
    {
        $encrypted = '';
        $pi_key = openssl_pkey_get_private($this->PriKye);//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
        //最大允许加密长度为117，得分段加密
        $plainData = str_split($data, 100);//生成密钥位数 1024 bit key
        foreach ($plainData as $chunk) {
            $partialEncrypted = '';
            $encryptionOk = openssl_private_encrypt($chunk, $partialEncrypted, $pi_key);//私钥加密
            if ($encryptionOk === false) {
                return false;
            }
            $encrypted .= $partialEncrypted;
        }

        $encrypted = base64_encode($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
        return $encrypted;
    }


    /**
     * RSA公钥解密(私钥加密的内容通过公钥可以解密出来)
     * @param string $public_key 公钥
     * @param string $data 私钥加密后的字符串
     * @return string $decrypted 返回解密后的字符串
     * @author mosishu
     */
    public function publicDecrypt($data)
    {
        $decrypted = '';
        $pu_key = openssl_pkey_get_public($this->PubKey);//这个函数可用来判断公钥是否是可用的
        $plainData = str_split(base64_decode($data), 128);//生成密钥位数 1024 bit key
        foreach ($plainData as $chunk) {
            $str = '';
            $decryptionOk = openssl_public_decrypt($chunk, $str, $pu_key);//公钥解密
            if ($decryptionOk === false) {
                return false;
            }
            $decrypted .= $str;
        }
        return $decrypted;
    }
 /**
     * 获取Rsa私钥
     *
     * @return string
     */
    private function _getRsaPriKey ()
    {$rsaPriKey = <<<EOF
-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----
EOF;
        return $rsaPriKey;
    }

    private function _getRsaPubKey()
    {
        $rsaPubKey = <<<EOF
-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQClJRR/aFU2/WFGJa3kFmzd8tuR
vZjyiMBDpACbROuaPfUkfyudVc9UExeercoNa20q3cIqZoDgAEpvShqMiXBqzkwH
rzGqJKeZP/gFoJaNLdnC175PmBqsXit8H6QE8PNnuJk4bSQWz6leAwi9EcEpeaQO
m1CJBADBE10bio71kQIDAQAB
-----END PUBLIC KEY-----
EOF;
        return $rsaPubKey;


    }


}

这是一个私匙 加密 公匙 解密的类 ，调用

$ps = new Rsa();
$str = '我是谁，我在哪';
echo $ps->privateEncrypt($str);

结果：

F9ijWmD5EOjUbu3dHKMCoDZlITt0YaNeEEcBlENpQggtRtqnVZKqfe0DdUZzB6bQGt8bMl0eV13Ss/2e8XBDBfJ4ZK08oCYrwvbemyy4x/43HfJTgbJmoDJyKUZYu3CfL83oZrNAB2U59vEOG5DXcZlV0sHCBZdSXgAlkqU88fM=

下面解密：

$ps = new Rsa();
$str = '我是谁，我在哪';

echo $ps->publicDecrypt($ps->privateEncrypt($str));

结果：

image.png

同理、公匙加密 私匙 解密也是同样的道理，下面附上源码：

<?php

class Rsa
{
    private $PriKye;
    private $PubKey;
    public function __construct()
    {
        $this->PriKye = $this->_getRsaPriKey();
        $this->PubKey = $this->_getRsaPubKey();
    }

    /**
     * RSA私钥加密
     * @param string $private_key 私钥
     * @param string $data 要加密的字符串
     * @return string $encrypted 返回加密后的字符串
     * @author mosishu
     */
    public function privateEncrypt( $data)
    {
        $encrypted = '';
        $pi_key = openssl_pkey_get_private($this->PriKye);//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
        //最大允许加密长度为117，得分段加密
        $plainData = str_split($data, 100);//生成密钥位数 1024 bit key
        foreach ($plainData as $chunk) {
            $partialEncrypted = '';
            $encryptionOk = openssl_private_encrypt($chunk, $partialEncrypted, $pi_key);//私钥加密
            if ($encryptionOk === false) {
                return false;
            }
            $encrypted .= $partialEncrypted;
        }

        $encrypted = base64_encode($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
        return $encrypted;
    }


    /**
     * RSA公钥解密(私钥加密的内容通过公钥可以解密出来)
     * @param string $public_key 公钥
     * @param string $data 私钥加密后的字符串
     * @return string $decrypted 返回解密后的字符串
     * @author mosishu
     */
    public function publicDecrypt($data)
    {
        $decrypted = '';
        $pu_key = openssl_pkey_get_public($this->PubKey);//这个函数可用来判断公钥是否是可用的
        $plainData = str_split(base64_decode($data), 128);//生成密钥位数 1024 bit key
        foreach ($plainData as $chunk) {
            $str = '';
            $decryptionOk = openssl_public_decrypt($chunk, $str, $pu_key);//公钥解密
            if ($decryptionOk === false) {
                return false;
            }
            $decrypted .= $str;
        }
        return $decrypted;
    }


    //RSA公钥加密
    public function publicEncrypt( $data)
    {
        $encrypted = '';
        $pu_key = openssl_pkey_get_public($this->PubKey);
        $plainData = str_split($data, 100);
        foreach ($plainData as $chunk) {
            $partialEncrypted = '';
            $encryptionOk = openssl_public_encrypt($chunk, $partialEncrypted, $pu_key);//公钥加密
            if ($encryptionOk === false) {
                return false;
            }
            $encrypted .= $partialEncrypted;
        }
        $encrypted = base64_encode($encrypted);
        return $encrypted;
    }


    //RSA私钥解密
    public function privateDecrypt( $data)
    {
        $decrypted = '';
        $pi_key = openssl_pkey_get_private($this->PriKye);
        $plainData = str_split(base64_decode($data), 128);
        foreach ($plainData as $chunk) {
            $str = '';
            $decryptionOk = openssl_private_decrypt($chunk, $str, $pi_key);//私钥解密
            if ($decryptionOk === false) {
                return false;
            }
            $decrypted .= $str;
        }
        return $decrypted;
    }

    /**
     * 获取Rsa私钥
     *
     * @return string
     */
    private function _getRsaPriKey ()
    {$rsaPriKey = <<<EOF
-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----
EOF;
        return $rsaPriKey;
    }

    private function _getRsaPubKey()
    {
        $rsaPubKey = <<<EOF
-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQClJRR/aFU2/WFGJa3kFmzd8tuR
vZjyiMBDpACbROuaPfUkfyudVc9UExeercoNa20q3cIqZoDgAEpvShqMiXBqzkwH
rzGqJKeZP/gFoJaNLdnC175PmBqsXit8H6QE8PNnuJk4bSQWz6leAwi9EcEpeaQO
m1CJBADBE10bio71kQIDAQAB
-----END PUBLIC KEY-----
EOF;
        return $rsaPubKey;


    }


}

可以到 http://web.chacuo.net/netrsakeypair这个网站，在线生成公钥和私钥