PHP | openssl_public_decrypt() Function

Hello folks! welcome back to a new edition of our tutorial on PHP. In this tutorial guide, we are going to be studying about the PHP openssl_public_decrypt() Function.

The openssl_public_decrypt() function is used to decrypt the data with public key.

This function decrypts the data that was encrypted using openssl_private_encrypt() function.

syntax

Following below is the syntax to use this function -

openssl_public_decrypt ( string $data , string &$decrypted , mixed $key [, int $padding = OPENSSL_PKCS1_PADDING ] ) : bool

READ: PHP | openssl_public_encrypt() Function

Parameter Details

Sr.No	Parameter	Description
1	data	The data encrypted using openssl_private_encrypt().
2	decrypted	It will have the data that is decrypted.
3	key	The public key.
4	padding	The padding you can apply are : OPENSSL_PKCS1_PADDING, OPENSSL_NO_PADDING.

Return Value

This PHP function returns true on success or false on failure.

PHP Version

This PHP function works from PHP version greater than 5.0.0.

Example1

The following example below illustrates the usage of the openssl_private_encrypt() and the openssl_public_decrypt() functions for the encryption and decryption of data -

<?php
   // Save Private Key
   $privkey = openssl_pkey_new();
   openssl_pkey_export_to_file($privkey, 'C:/xampp/htdocs/modules/openssl/privatekey.pem');
	
   // To encrpt data
   $data = 'Welcome To WebDesignTutorialz';
   $isvalid = openssl_private_encrypt ($data, $crypted , file_get_contents('C:/xampp/htdocs/modules/openssl/privatekey.pem'),OPENSSL_PKCS1_PADDING);	
   echo "Data encryption : ".$crypted;
   echo ">br/<>br/<";
	
   //Save Public Key
   $dn = array(
      "countryName" => "NG",
      "stateOrProvinceName" => "Rivers",
      "localityName" => "test1",
      "organizationName" => "test2",
      "organizationalUnitName" => "test3",
      "commonName" => "www.test.com",
      "emailAddress" => "xyz@test.com"
   );
   $cert = openssl_csr_new($dn, $privkey);
   $cert = openssl_csr_sign($cert, null, $privkey, 365);
   openssl_x509_export_to_file($cert, 'C:/xampp/htdocs/modules/openssl/publickey.pem');
		
   if ($isvalid) {	
      openssl_public_decrypt ($crypted, $decrypted , file_get_contents('C:/xampp/htdocs/modules/openssl/publickey.pem'),OPENSSL_PKCS1_PADDING);	
      echo "Data decryption : ".$decrypted;
   }
?>

Output

When the above code is executed, it will produce the following result -

Data encryption : k��G��7)xy{�N3Г�x<�J^�gd��Ψ�I?{��<�Ws3�mW$��h��(F;tJ�J�W��|�9L�vL��xF��f��,�(N�ΰ��n���Y%Oo,�2��Qh��G�|-��}���1�6Tm�qS�wb���[�i�-r�F��rQhZ��$�� ��U�pMC��Y�n�0,Z�CuG��8�h��@4f��7ؕ�w��;��d��ʈ��$�I^�Z��at��?�

Data decryption : Welcome To WebDesignTutorialz

Example2

The following example below illustrates the usage of the openssl_private_encrypt() and the openssl_public_decrypt() functions for encrypting and decrypting file content -

<?php
   // Save Private Key
   $privkey = openssl_pkey_new();
   openssl_pkey_export_to_file($privkey, 'C:/xampp/htdocs/modules/openssl/privatekey.pem');
	
   // To encrpt data
   $data = file_get_contents('C:/xampp/htdocs/modules/openssl/test.txt');
   $isvalid = openssl_private_encrypt ($data, $crypted , file_get_contents('C:/xampp/htdocs/modules/openssl/privatekey.pem'),OPENSSL_PKCS1_PADDING);	
   echo "Data encryption : ".$crypted;
   echo ">br/<>br/<";
	
   //Save Public Key
   $dn = array(
      "countryName" => "NG",
      "stateOrProvinceName" => "Rivers",
      "localityName" => "test1",
      "organizationName" => "test2",
      "organizationalUnitName" => "test3",
      "commonName" => "www.test.com",
      "emailAddress" => "xyz@test.com"
   );
   $cert = openssl_csr_new($dn, $privkey);
   $cert = openssl_csr_sign($cert, null, $privkey, 365);
   openssl_x509_export_to_file($cert, 'C:/xampp/htdocs/modules/openssl/publickey.pem');
		
   if ($isvalid) {	
      openssl_public_decrypt ($crypted, $decrypted , file_get_contents('C:/xampp/htdocs/modules/openssl/publickey.pem'),OPENSSL_PKCS1_PADDING);	
      echo "Data decryption : ".$decrypted;
   }
?>

Output

When the above code is executed, it will produce the following result -

Data encryption : ��V*�+@4CҺX�i�mM6� ��,?�F,��+�q ��@��g�N6c<*eh��:��5Z��&�&'+= �
��b��J�r ��aO�@gƝ��m�Gy�4W2�ҋ��%��pX@�k�DW�fEW��$j�>i��~��1���w�m}���}�����5I��x� ��H�*A8�� ��U�7~°��F�}4����DV�MZ��望C �'C��-�7�f�

Data decryption : This is data encryption test using openssl php module.

READ: PHP | openssl_private_encrypt() Function

Alright guys! This is where we are going to be rounding up for this tutorial post. In our next tutorial, we will be studying about the openssl_private_decrypt() Function.

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