(PHP 4 >= 4.2.0, PHP 5)
openssl_x509_export — Exports a certificate as a string
openssl_x509_export() stores x509 into a string named by output in a PEM encoded format.
参见密钥/证书参数以获取有效值列表。
On success, this will hold the PEM.
The optional parameter notext affects the verbosity of the output; if it is FALSE, then additional human-readable information is included in the output. The default value of notext is TRUE.
成功时返回 TRUE， 或者在失败时返回 FALSE.