The following script works fine. The zip is encrypted, txt file created, and immediately decrypted successfully, and the new zip is created successfully.
However, if I run the decrypt portion only subsequently, it fails to decrypt the txt file. It returns an empty $original_plaintext variable and the final zip has size 0. The $key and $iv are not changed for the second run. Security is not the issue - I just need a scrambled text file and then need to be able to decrypt it later.
$key = "sometext";
$iv = "someothertext";
$cipher = "aes-128-gcm";
$tag = NULL;
$fileRoot = "sql_2018_11_10";
if (in_array($cipher, openssl_get_cipher_methods())) {
// Encrypt
$plaintext = file_get_contents("tmp/$fileRoot.zip");
$ciphertext = openssl_encrypt($plaintext, $cipher, $key, $options=0, $iv, $tag);
file_put_contents("tmp/enc_$fileRoot.txt", $ciphertext);
// Decrypt
$ciphertext = file_get_contents("tmp/enc_$fileRoot.txt");
$original_plaintext = openssl_decrypt($ciphertext, $cipher, $key, $options=0, $iv, $tag);
file_put_contents("tmp/uenc_$fileRoot.zip", $original_plaintext);
}
Related
I have this PHP Code for encryption and decryption. This is using OpenSSL
<?php
//$key should have been previously generated in a cryptographically safe way, like
openssl_random_pseudo_bytes
$plaintext = "message to be encrypted";
$cipher = "aes-128-gcm";
if (in_array($cipher, openssl_get_cipher_methods()))
{
$ivlen = openssl_cipher_iv_length($cipher);
$iv = openssl_random_pseudo_bytes($ivlen);
$ciphertext = openssl_encrypt($plaintext, $cipher, $key, $options=0, $iv, $tag);
//store $cipher, $iv, and $tag for decryption later
$original_plaintext = openssl_decrypt($ciphertext, $cipher, $key, $options=0, $iv, $tag);
echo $original_plaintext."\n";
}
?>
When you run this on your browser and refresh the page the encryption changes. So I want to know how do I use a check like if statement to see if the user input plain text matches the encrypted text.
i'm having some trouble decrypting a string that was encrypted using openssl. I don't have access to change the encryption code, but i do have read access:
Encrypt code (unable to modify)
<?php
$key = hex2bin("24a5d2b96b9aee2fb515c94fb36da508");
$encryptTxt = openssl_encrypt(
"txt to encrypt",
'AES-128-ECB',
$key
);
?>
link
Here is how I have attempted to decrypt:
decrypt.php
$ciphertext = $_GET['un'];
$cipher = "aes-128-ecb";
$key = hex2bin("24a5d2b96b9aee2fb515c94fb36da508");
$original_plaintext = openssl_decrypt($ciphertext, $cipher, $key);
echo "text= " . $original_plaintext;
The decrypted text is not returned on the decrypt page
SOLVED: I updated decrypt.php to the following and it returned the decrypted text
$ciphertext = $_GET['un'];
$ciphertext = hex2bin($ciphertext);
$ciphertext = base64_encode($ciphertext);
$cipher = "aes-128-ecb";
$key = hex2bin("24a5d2b96b9aee2fb515c94fb36da508");
$original_plaintext = openssl_decrypt($ciphertext, $cipher, $key);
echo "text= " . $original_plaintext;
I'm having problem with decrypting
I have
$key="Gwu078980";
$cipher="aes-128-gcm";
$iv=md5($cipher);
$text="yaw0";
$tag="";
echo $encrypted=openssl_encrypt($text, $cipher, $key, 0, $iv, $tag);
echo $de_ciphertext=openssl_decrypt($encrypted, $cipher, $key, 0, $iv, $tag);
Output
ELRmWQ==
yaw0
So the raw text is yaw0 and the encrypted is ELRmWQ== and the decrypted is yaw0 so perfect.
But when I manually copy the encrypted text and use it as
$encrypted ="ELRmWQ==";
And I run the decryption
the decryption returns null.
Thanks in advance for anyone to help me out.
Your openssl_encrypt message modifies $tag by reference since you're using aes-128-gcm.
That parameter is required for openssl_decrypt aswell (when using AEAD - Authenticated Encryption and Decryption) and is probably an empty string in your case when you omit the openssl_encrypt call.
See Example 1 in the docs:
The comment about storing $cipher, $iv, and $tag is the important part:
<?php
//$key should have been previously generated in a cryptographically safe way, like openssl_random_pseudo_bytes
$plaintext = "message to be encrypted";
$cipher = "aes-128-gcm";
if (in_array($cipher, openssl_get_cipher_methods()))
{
$ivlen = openssl_cipher_iv_length($cipher);
$iv = openssl_random_pseudo_bytes($ivlen);
$ciphertext = openssl_encrypt($plaintext, $cipher, $key, $options=0, $iv, $tag);
//store $cipher, $iv, and $tag for decryption later
$original_plaintext = openssl_decrypt($ciphertext, $cipher, $key, $options=0, $iv, $tag);
echo $original_plaintext."\n";
}
?>
I want to encrypt html data before saving in Database.
this is a sample html text:
<p>test data in normal text</p> <p><b>test data in bold text</b></p> <p><i>test data in italics text</i></p> <p><b><i>test data in bold and italics text</i></b><br></p>
Can anyone help me to find a solution.
use can use OpenSSL encrypt
$plaintext = "message to be encrypted";
$cipher = "aes-128-gcm";
if (in_array($cipher, openssl_get_cipher_methods()))
{
$ivlen = openssl_cipher_iv_length($cipher);
$iv = openssl_random_pseudo_bytes($ivlen);
$ciphertext = openssl_encrypt($plaintext, $cipher, $key, $options=0, $iv, $tag);
//store $cipher, $iv, and $tag for decryption later
$original_plaintext = openssl_decrypt($ciphertext, $cipher, $key, $options=0, $iv, $tag);
echo $original_plaintext."\n";
}
check following link for more detail
http://php.net/manual/en/function.openssl-encrypt.php
I am trying to encrypt/decrypt files in PHP. So far I am successful with .txt files but when it comes to .pdf and .doc or .docx my code fails, i.e. it gives absurd results. Can anyone suggest modification/alternative in my code? Thanks in advance!
Here's the encryption function
function encryptData($value)
{
$key = "Mary has one cat";
$text = $value;
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $text, MCRYPT_MODE_ECB, $iv);
return $crypttext;
}
Here's the decryption function
function decryptData($value)
{
$key = "Mary has one cat";
$crypttext = $value;
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$decrypttext = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $crypttext, MCRYPT_MODE_ECB, $iv);
return trim($decrypttext);
}
I used this blog to help me encrypt/decrypt pdf files on my local machine using openssl_encrypt because mcrypt is deprecated in php7.
First, you get the file contents of the pdf:
$msg = file_get_contents('example.pdf');
Then I called the encryption function written in the blog post:
$msg_encrypted = my_encrypt($msg, $key);
Then I open the file I want to write to and write the new encrypted msg:
$file = fopen('example.pdf', 'wb');
fwrite($file, $msg_encrypted);
fclose($file);
For reference, in case that blog goes down, here are the encryption and decryption functions from the blog:
$key = 'bRuD5WYw5wd0rdHR9yLlM6wt2vteuiniQBqE70nAuhU=';
function my_encrypt($data, $key) {
// Remove the base64 encoding from our key
$encryption_key = base64_decode($key);
// Generate an initialization vector
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length('aes-256-cbc'));
// Encrypt the data using AES 256 encryption in CBC mode using our encryption key and initialization vector.
$encrypted = openssl_encrypt($data, 'aes-256-cbc', $encryption_key, 0, $iv);
// The $iv is just as important as the key for decrypting, so save it with our encrypted data using a unique separator (::)
return base64_encode($encrypted . '::' . $iv);
}
function my_decrypt($data, $key) {
// Remove the base64 encoding from our key
$encryption_key = base64_decode($key);
// To decrypt, split the encrypted data from our IV - our unique separator used was "::"
list($encrypted_data, $iv) = explode('::', base64_decode($data), 2);
return openssl_decrypt($encrypted_data, 'aes-256-cbc', $encryption_key, 0, $iv);
}