This function DOES return TRUE if the key has a passphrase, you just need to set up the data in such a way that the function can understand it. It is not documented here.
This error message led me to the solution:
PHP Warning: openssl_x509_check_private_key(): key array must be of the form array(0 => key, 1 => phrase)
So this works:
$certFile = file_get_contents('cert.crt');
$keyFile = file_get_contents('cert.key');
$keyPassphrase = "password1234";
$keyCheckData = array(0=>$keyFile,1=>$keyPassphrase);
$result = openssl_x509_check_private_key($certFile,$keyCheckData);
openssl_x509_check_private_key
(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
openssl_x509_check_private_key — 检查私钥是否对应于证书
说明
检查给定的私钥 key 是否和证书 cert 对应。
警告
这个函数不会检查密钥key是否真的是私钥。
它只是比较了和密钥匹配的公共材料 (比如，RSA密钥的指数和模量) 和/或密钥参数(比如，EC密钥的参数)。
这也意味着，比如，提供给key赋一个公钥值，该函数可能返回 true.
参数
-
cert -
证书。
-
key -
私钥。
返回值
如果给定的私钥 key 和证书 cert对应， 返回true 否则返回 false .
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User Contributed Notes 2 notes
tomsie at toms dot ie ¶
6 years ago
jared at enhancesoft dot com ¶
9 years ago
This function will return FALSE if the private key requires a pass phrase.
