mcrypt_encrypt

Encrypts plaintext with given parameters

&warn.deprecated.function-7-1-0.removed-7-2-0;
&reftitle.description; ``string``false```mcrypt_encrypt` `string` `cipher` `string` `key` `string` `data` `string` `mode` `string` `iv`

Encrypts the data and returns it.

&reftitle.parameters;

`cipher`

- &mcrypt.parameter.cipher;

`key`

- The key with which the data will be encrypted. If the provided key size is not supported by the cipher, the function will emit a warning and return &false;

`data`

- The data that will be encrypted with the given `cipher` and `mode`. If the size of the data is not n * blocksize, the data will be padded with '`\0`'.

  The returned crypttext can be larger than the size of the data that was given by `data`.

`mode`

- &mcrypt.parameter.mode;

`iv`

- &mcrypt.parameter.iv.strict;
&reftitle.returnvalues;

Returns the encrypted data as a string &return.falseforfailure;.

&reftitle.examples;

### `mcrypt_encrypt` Example

    <?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";
    ?>

&example.outputs;

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

&reftitle.seealso;

- `mcrypt_decrypt`
- `mcrypt_module_open`