openssl_pkey_get_public

(PHP 4 >= 4.2.0, PHP 5)

openssl_pkey_get_public — 証明書から公開鍵を抽出し、使用できるようにする

説明

resource openssl_pkey_get_public ( mixed $certificate )

openssl_get_publickey() は公開鍵を certificate から抽出し、他の関数で使用できるよう準備します。

パラメータ

certificate

certificate は以下のいずれかです。

an X.509 証明書リソース
file://path/to/file.pem 形式の文字列。このファイルは、PEM エンコードされた証明書/秘密鍵である必要があります（両方を含むことも可能です）。
PEM フォーマットの秘密鍵。

返り値

成功した場合に正のキーリソース ID、エラー時に FALSE を返します。

openssl_pkey_new

openssl_pkey_get_private

Last updated: Fri, 30 Jan 2009

add a note User Contributed Notes
openssl_pkey_get_public

thelen dot shar at gmail dot com
25-Jan-2009 10:08


Found it difficult to get my head around this due to lack of documentation.



But the process I followed for all this was:

Generate private key:

openssl genrsa -des3 -out private.pem 1024



Generate public key:

openssl rsa -in private.pem -out public.pem -outform PEM -pubout



Then in PHP:

$passphrase = 'somestring';

$key_private = openssl_get_privatekey(file_get_contents('private.pem'), $passphrase);

$key_public = openssl_get_publickey(file_get_contents('public.pem'));



Probably not the best way of doing it, but a lot simpler than the other examples on the site. I was having trouble getting the pubkey, it wasn't exactly specified very well, and I had made a mistake in generating it so it wasn't working for that reason as well.

VaD
06-Jun-2008 08:36


Small error in this code:



$pub_key = openssl_pkey_get_public(file_get_contents('./cert.crt'));

$keyData = openssl_pkey_get_details($pub_key);

file_put_contents('./key.pub', $keyData['key']);

07-May-2007 10:40


you can get (and save to file) public key using openssl_pkey_get_details(resource $key ) function:



<?php

$pub_key = openssl_pkey_get_public(file_get_contents('./cert.crt'));

$keyData = openssl_pkey_get_details($pub_key);

fule_put_contents('./key.pub', $keyData['key']);

?>

dankybastard at hotmail
09-Feb-2005 06:52


You must also use the string representation of the certificate to get the public key resource:



$dn = array();  // use defaults

$res_privkey = openssl_pkey_new();

$res_csr = openssl_csr_new($dn, $res_privkey);

$res_cert = openssl_csr_sign($res_csr, null, $res_privkey, $ndays);



openssl_x509_export($res_cert, $str_cert);



$res_pubkey = openssl_pkey_get_public($str_cert);

09-Aug-2004 09:44


This documentation notes it can take a PEM-formatted private key, but as per bug #25614, this is not possible in any form. The function simply returns a FALSE.



The only thing you can get public keys out of are X.509 certificates.



Furthermore, there is NO way to export a public key into a PEM-encoded form.

add a note

openssl_pkey_new

openssl_pkey_get_private

Last updated: Fri, 30 Jan 2009