PHP SSL Certificate Get Keysize



<?php
$x509_certificate_pem='-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----';
 
$public_key_res = openssl_pkey_get_public($x509_certificate_pem);
if (($error_string = openssl_error_string())!==false)
{
    error_log("OPENSSL ERR: ".$error_string);
}
else
{
    $public_key_arr = openssl_pkey_get_details($public_key_res);
    $keysize = isset($public_key_arr['bits'])? $public_key_arr['bits'] : 0;
    $key_type = 'unknown';
    $key_type = $public_key_arr['type']==OPENSSL_KEYTYPE_RSA ? 'RSA' : $key_type;
    $key_type = $public_key_arr['type']==OPENSSL_KEYTYPE_DSA ? 'DSA' : $key_type;
    $key_type = $public_key_arr['type']==OPENSSL_KEYTYPE_DH ?  'DH'  : $key_type;
    echo $key_type.' / '.$keysize ."\n";
}
?>

output:
RSA / 2048