怎样对邮件正文分段加密及解密解决思路

怎样对邮件正文分段加密及解密
--------php 源码-------------

PHP code

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->$mailcont = "邮件正文………超过1024字节………邮件正文";    $crtpath = "/usr/nc-home/webpost/mailbox/d00/1/y/u/yushuai.niu/.user/certkey/wxd.crt";    exec("chmod 777 {$crtpath}");    $fp = fopen($crtpath, "r");    $crt = fread($fp, 8192);    fclose($fp);    $pubKey = openssl_get_publickey($crt);    //从证书中解析公钥    $keyData = openssl_pkey_get_details($pubKey);    $blocks = str_split($mailcont, 1000);    foreach ($blocks as $block) {    //公钥加密    if (!openssl_public_encrypt($block, $chrtext, $keyData['key'])) {    echo "<br>" . openssl_error_string() . "<br>";    }    $chrtext .= $chrtext;    }    echo "chrtext-->>>$chrtext<br>";    $keypath = "/usr/nc-home/webpost/mailbox/d00/1/y/u/yushuai.niu/.user/secretkey/wxd.key";    exec("chmod 777 {$keypath}");    $fp = fopen($keypath, "r");    $key = fread($fp, 8192);    fclose($fp);    $cipher = openssl_pkey_get_private($key);    openssl_private_decrypt($chrtext, $dcyCont, $cipher);    echo "dcyCont-->>>$dcyCont<br>";

-------------------错误响应----------------
error:0906D06C:PEM routines:PEM_read_bio:no start line

error:0406D06E:rsa routines:RSA_padding_add_PKCS1_type_2:data too large for key size

chrtext-->>>叔??騈蕈50后帞 氧(蘗因T繥r'Um淤?/閥f貸f?,?? %vY筊諬?粁`樇昀?煲? ?枹??妎5傊([email protected]?)Q耂o瑂駾鉌t饧k[F0鴎叔??騈蕈50后帞 氧(蘗因T繥r'Um淤?/閥f貸f?,?? %vY筊諬?粁`樇昀?煲? ?枹??妎5傊([email protected]?)Q耂o瑂駾鉌t饧k[F0鴎
dcyCont-->>>
--------------------
证书及私钥 绝对正确，只是openssl_public_encrypt()函数貌似不能循环加密？求解！！！


------解决方案--------------------
文件太大了,把要加密的内容弄成一部分一部分进行加密
------解决方案--------------------
str_split($mailcont, 100); 你有可能把中文字符串给拆开了！
------解决方案--------------------
加密是大事，但是别的邮件服务商不会解你的密吧。纠结中。加还是不加