PHP - Function openssl_public_decrypt()

Quiz

Definition and Usage

The openssl_public_decrypt() function will decrypt the data with the public key.

Description

Using function openssl_public_decrypt() will decrypt the data that was encrypted using openssl_private_encrypt().

Syntax

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

Parameters

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 Values

PHP openssl_public_decrypt() function returns TRUE on success or FALSE on failure.

PHP Version

This function will work from PHP Version greater than 5.0.0.

Example 1

To encrypt data using openssl_private_encrypt() and decrypt using openssl_public_decrypt():

<?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 TuorialsPoint';
   $isvalid = openssl_private_encrypt ($data, $crypted , file_get_contents('C:/xampp/htdocs/modules/openssl/privatekey.pem'),OPENSSL_PKCS1_PADDING);	
   echo "Data encryption : ".$crypted;
   echo ">br/<>br/&lt";
	
   //Save Public Key
   $dn = array(
      "countryName" => "IN",
      "stateOrProvinceName" => "Karnataka",
      "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;
   }
?>

This will produce the following result:

Data encryption : kG7)xy{N3x

Example 2
To encrypt file content using openssl_private_encrypt() and decrypt using  openssl_public_decrypt():
<?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/&lt";
	
   //Save Public Key
   $dn = array(
      "countryName" => "IN",
      "stateOrProvinceName" => "Karnataka",
      "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;
   }
?>

This will produce the following result:
Data encryption : V*+@4CXimM6 ,?F,+q @gN6ci~1wm}}5Ix H*A8 U7~F}4DVMZC 'C-7f

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


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