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openssl_private_decrypt

(PHP 4 >= 4.0.6, PHP 5, PHP 7, PHP 8)

openssl_private_decrypt — Decrypts data with private key

Description

function openssl_private_decrypt(
    string $data,
    #[\SensitiveParameter]string &$decrypted_data,
    #[\SensitiveParameter]OpenSSLAsymmetricKey|OpenSSLCertificate|array|string $private_key,
    int $padding = OPENSSL_PKCS1_PADDING,
    ?string $digest_algo = null
): bool

openssl_private_decrypt() decrypts data that was previously encrypted via openssl_public_encrypt() and stores the result into decrypted_data.

You can use this function e.g. to decrypt data which is supposed to only be available to you.

Parameters

data
decrypted_data
private_key: private_key must be the private key that corresponds to the public key that was used to encrypt the data.
padding: padding can be one of OPENSSL_PKCS1_PADDING, OPENSSL_SSLV23_PADDING, OPENSSL_PKCS1_OAEP_PADDING, OPENSSL_NO_PADDING.
digest_algo: The digest algorithm for OAEP padding, or null to use the default algorithm.

Return Values

Returns true on success or false on failure.

Changelog

Version	Description
8.5.0	The optional parameter `digest_algo` has been added.
8.0.0	`private_key` accepts an OpenSSLAsymmetricKey or OpenSSLCertificate instance now; previously, a resource of type `OpenSSL key` or `OpenSSL X.509` was accepted.

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User Contributed Notes 1 note

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wfredkNOSPAM at L5DevelopmentNOSPAM dot com ¶

24 years ago

Encrypt using public key, decrypt using private key.

Use this to store stuff in your database: Unless someone
has your private key, the database contents are useless.

Also, use this for sending to a specific individual:  Get
their public key, encrypt the message, only they can use
their private key to decode it.

<?php
echo "Source: $source";
$fp=fopen("/path/to/certificate.crt","r");
$pub_key=fread($fp,8192);
fclose($fp);
openssl_get_publickey($pub_key);
/*
 * NOTE:  Here you use the $pub_key value (converted, I guess)
 */
openssl_public_encrypt($source,$crypttext,$pub_key);
echo "String crypted: $crypttext";

$fp=fopen("/path/to/private.key","r");
$priv_key=fread($fp,8192);
fclose($fp);
// $passphrase is required if your key is encoded (suggested)
$res = openssl_get_privatekey($priv_key,$passphrase);
/*
 * NOTE:  Here you use the returned resource value
 */
openssl_private_decrypt($crypttext,$newsource,$res);
echo "String decrypt : $newsource";
?>