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File: src/Discretion/SimpleCrypto.php

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File: src/Discretion/SimpleCrypto.php
Role: Class source
Content type: text/plain
Description: Class source
Class: Discretion
Show contact forms and deliver encrypted mail
Author: By
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Date: 4 months ago
Size: 3,126 bytes
 

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<?php
declare(strict_types=1);
namespace
ParagonIE\Discretion;

use
ParagonIE\ConstantTime\Base64UrlSafe;
use
ParagonIE\Discretion\Data\HiddenString;

/**
 * Class SimpleCrypto
 *
 * This class just encrypts data using XChaCha20-Poly1305, provided by libsodium.
 * By default, we opt for Base64url encoding on our ciphertext messages.
 *
 * Requires: ext/mbstring, paragonie/sodium_compat
 * Recommended: ext/sodium 2.0.7+, libsodium 1.0.15+
 *
 * @package ParagonIE\Discretion
 */
class SimpleCrypto
{
    const
MIN_CIPHERTEXT_LENGTH = 40;

   
/**
     * Decrypt a message with XChaCha20-Poly1305.
     *
     * @param string $ciphertext
     * @param HiddenString $key
     * @return HiddenString
     * @throws \Exception
     * @throws \InvalidArgumentException
     */
   
public static function decrypt(string $ciphertext, HiddenString $key): HiddenString
   
{
       
/** @var string $realCiphertext */
       
$realCiphertext = Base64UrlSafe::decode($ciphertext);
        if (!\
is_string($realCiphertext)) {
            throw new \
InvalidArgumentException('Invalid encoding');
        }
        return static::
decryptRaw($realCiphertext, $key);
    }

   
/**
     * Base64url-encoded encrypted message.
     *
     * @param HiddenString $message
     * @param HiddenString $key
     * @return string
     * @throws \SodiumException
     * @throws \TypeError
     */
   
public static function encrypt(HiddenString $message, HiddenString $key): string
   
{
        return
Base64UrlSafe::encode(
            static::
encryptRaw($message, $key)
        );
    }

   
/**
     * Decrypt a message with XChaCha20-Poly1305.
     *
     * @param string $ciphertext
     * @param HiddenString $key
     * @return HiddenString
     * @throws \Exception
     * @throws \InvalidArgumentException
     */
   
public static function decryptRaw(string $ciphertext, HiddenString $key): HiddenString
   
{
        if (\
mb_strlen($ciphertext, '8bit') < static::MIN_CIPHERTEXT_LENGTH) {
            throw new \
InvalidArgumentException('Ciphertext is too short.');
        }
       
$nonce = \mb_substr($ciphertext, 0, 24, '8bit');
       
$message = \mb_substr($ciphertext, 24, null, '8bit');

       
$plaintext = \ParagonIE_Sodium_Compat::crypto_aead_xchacha20poly1305_ietf_decrypt(
           
$message,
           
$nonce,
           
$nonce,
           
$key->getString()
        );
        if (!\
is_string($plaintext)) {
            throw new \
Exception('Decryption failed');
        }
        return new
HiddenString($plaintext);
    }

   
/**
     * Encrypt a message with XChaCha20-Poly1305.
     *
     * @param HiddenString $message
     * @param HiddenString $key
     * @return string
     * @throws \SodiumException
     * @throws \TypeError
     */
   
public static function encryptRaw(HiddenString $message, HiddenString $key): string
   
{
       
$nonce = \random_bytes(24);
        return
$nonce . \ParagonIE_Sodium_Compat::crypto_aead_xchacha20poly1305_ietf_encrypt(
               
$message->getString(),
               
$nonce,
               
$nonce,
               
$key->getString()
            );
    }
}

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