mcrypt_encrypt

PHP 4 >= 4.0.2, PHP 5, PHP 7 < 7.2.0, PECL mcrypt >= 1.0.0

mcrypt_encrypt - Encrypts plaintext with given parameters

Code Examples

Example #1 mcrypt_encrypt Example

Result: Key size: 32 ENJW8mS2KaJoNB5E5CoSAAu0xARgsR1bdzFWpEn+poYw45q+73az5kYi4j+0haevext1dGrcW8Qi59txfCBV8BBj3bzRP3dFCp3CPQSJ8eU= This string was AES-256 / CBC / ZeroBytePadding encrypted.

<?php
    # --- ENCRYPTION ---
    # the key should be random binary, use scrypt, bcrypt or PBKDF2 to
    # convert a string into a key
    # key is specified using hexadecimal
    $key = pack('H*', "bcb04b7e103a0cd8b54763051cef08bc55abe029fdebae5e1d417e2ffb2a00a3");
    # show key size use either 16, 24 or 32 byte keys for AES-128, 192
    # and 256 respectively
    $key_size =  strlen($key);
    echo "Key size: " . $key_size . "\n";
    $plaintext = "This string was AES-256 / CBC / ZeroBytePadding encrypted.";
    # create a random IV to use with CBC encoding
    $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
    $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
    # creates a cipher text compatible with AES (Rijndael block size = 128)
    # to keep the text confidential 
    # only suitable for encoded input that never ends with value 00h
    # (because of default zero padding)
    $ciphertext = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key,
                                 $plaintext, MCRYPT_MODE_CBC, $iv);
    # prepend the IV for it to be available for decryption
    $ciphertext = $iv . $ciphertext;
    # encode the resulting cipher text so it can be represented by a string
    $ciphertext_base64 = base64_encode($ciphertext);
    echo  $ciphertext_base64 . "\n";
    # === WARNING ===
    # Resulting cipher text has no integrity or authenticity added
    # and is not protected against padding oracle attacks.
    # --- DECRYPTION ---
    $ciphertext_dec = base64_decode($ciphertext_base64);
    # retrieves the IV, iv_size should be created using mcrypt_get_iv_size()
    $iv_dec = substr($ciphertext_dec, 0, $iv_size);
    # retrieves the cipher text (everything except the $iv_size in the front)
    $ciphertext_dec = substr($ciphertext_dec, $iv_size);
    # may remove 00h valued characters from end of plain text
    $plaintext_dec = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key,
                                    $ciphertext_dec, MCRYPT_MODE_CBC, $iv_dec);
    echo  $plaintext_dec . "\n";

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mcrypt_encrypt

Example #1 mcrypt_encrypt Example

Function mcrypt_encrypt:

Mcrypt Functions

Most used PHP functions