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<title>Encrypts plaintext with given parameters</title>
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<h1 class="refname">mcrypt_encrypt</h1>
<p class="verinfo">(PHP 4 >= 4.0.2, PHP 5)</p><p class="refpurpose"><span class="refname">mcrypt_encrypt</span> — <span class="dc-title">Encrypts plaintext with given parameters</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.mcrypt-encrypt-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">string</span> <span class="methodname"><strong>mcrypt_encrypt</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$cipher</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$key</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$data</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$mode</code></span>
[, <span class="methodparam"><span class="type">string</span> <code class="parameter">$iv</code></span>
] )</div>
<p class="para rdfs-comment">
Encrypts the data and returns it.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.mcrypt-encrypt-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">cipher</code></em></span>
<dd>
<p class="para">One of the <strong><code>MCRYPT_ciphername</code></strong> constants, or the name of the algorithm as string.</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">key</code></em></span>
<dd>
<p class="para">
The key with which the data will be encrypted. If it's smaller than
the required keysize, it is padded with '<em>\0</em>'. It is
better not to use ASCII strings for keys.
</p>
<p class="para">
It is recommended to use the mhash functions to create a key from a
string.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">data</code></em></span>
<dd>
<p class="para">
The data that will be encrypted with the given <em><code class="parameter">cipher</code></em>
and <em><code class="parameter">mode</code></em>. If the size of the data is not n * blocksize,
the data will be padded with '<em>\0</em>'.
</p>
<p class="para">
The returned crypttext can be larger than the size of the data that was
given by <em><code class="parameter">data</code></em>.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">mode</code></em></span>
<dd>
<p class="para">One of the <strong><code>MCRYPT_MODE_modename</code></strong> constants, or one of the following strings: "ecb", "cbc", "cfb", "ofb", "nofb" or "stream".</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">iv</code></em></span>
<dd>
<p class="para">Used for the initialization in CBC, CFB, OFB modes, and in some algorithms in STREAM mode. If you do not supply an IV, while it is needed for an algorithm, the function issues a warning and uses an IV with all its bytes set to "<em>\0</em>".</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.mcrypt-encrypt-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns the encrypted data, as a string.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.mcrypt-encrypt-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-843">
<p><strong>Example #1 <span class="function"><strong>mcrypt_encrypt()</strong></span> Example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /> </span><span style="color: #FF8000"># --- ENCRYPTION ---<br /><br /> # the key should be random binary, use scrypt, bcrypt or PBKDF2 to<br /> # convert a string into a key<br /> # key is specified using hexadecimal<br /> </span><span style="color: #0000BB">$key </span><span style="color: #007700">= </span><span style="color: #0000BB">pack</span><span style="color: #007700">(</span><span style="color: #DD0000">'H*'</span><span style="color: #007700">, </span><span style="color: #DD0000">"bcb04b7e103a0cd8b54763051cef08bc55abe029fdebae5e1d417e2ffb2a00a3"</span><span style="color: #007700">);<br /> <br /> </span><span style="color: #FF8000"># show key size use either 16, 24 or 32 byte keys for AES-128, 192<br /> # and 256 respectively<br /> </span><span style="color: #0000BB">$key_size </span><span style="color: #007700">= </span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$key</span><span style="color: #007700">);<br /> echo </span><span style="color: #DD0000">"Key size: " </span><span style="color: #007700">. </span><span style="color: #0000BB">$key_size </span><span style="color: #007700">. </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /> <br /> </span><span style="color: #0000BB">$plaintext </span><span style="color: #007700">= </span><span style="color: #DD0000">"This string was AES-256 / CBC / ZeroBytePadding encrypted."</span><span style="color: #007700">;<br /><br /> </span><span style="color: #FF8000"># create a random IV to use with CBC encoding<br /> </span><span style="color: #0000BB">$iv_size </span><span style="color: #007700">= </span><span style="color: #0000BB">mcrypt_get_iv_size</span><span style="color: #007700">(</span><span style="color: #0000BB">MCRYPT_RIJNDAEL_128</span><span style="color: #007700">, </span><span style="color: #0000BB">MCRYPT_MODE_CBC</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$iv </span><span style="color: #007700">= </span><span style="color: #0000BB">mcrypt_create_iv</span><span style="color: #007700">(</span><span style="color: #0000BB">$iv_size</span><span style="color: #007700">, </span><span style="color: #0000BB">MCRYPT_RAND</span><span style="color: #007700">);<br /> <br /> </span><span style="color: #FF8000"># creates a cipher text compatible with AES (Rijndael block size = 128)<br /> # to keep the text confidential <br /> # only suitable for encoded input that never ends with value 00h<br /> # (because of default zero padding)<br /> </span><span style="color: #0000BB">$ciphertext </span><span style="color: #007700">= </span><span style="color: #0000BB">mcrypt_encrypt</span><span style="color: #007700">(</span><span style="color: #0000BB">MCRYPT_RIJNDAEL_128</span><span style="color: #007700">, </span><span style="color: #0000BB">$key</span><span style="color: #007700">,<br /> </span><span style="color: #0000BB">$plaintext</span><span style="color: #007700">, </span><span style="color: #0000BB">MCRYPT_MODE_CBC</span><span style="color: #007700">, </span><span style="color: #0000BB">$iv</span><span style="color: #007700">);<br /><br /> </span><span style="color: #FF8000"># prepend the IV for it to be available for decryption<br /> </span><span style="color: #0000BB">$ciphertext </span><span style="color: #007700">= </span><span style="color: #0000BB">$iv </span><span style="color: #007700">. </span><span style="color: #0000BB">$ciphertext</span><span style="color: #007700">;<br /> <br /> </span><span style="color: #FF8000"># encode the resulting cipher text so it can be represented by a string<br /> </span><span style="color: #0000BB">$ciphertext_base64 </span><span style="color: #007700">= </span><span style="color: #0000BB">base64_encode</span><span style="color: #007700">(</span><span style="color: #0000BB">$ciphertext</span><span style="color: #007700">);<br /><br /> echo </span><span style="color: #0000BB">$ciphertext_base64 </span><span style="color: #007700">. </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br /> </span><span style="color: #FF8000"># === WARNING ===<br /><br /> # Resulting cipher text has no integrity or authenticity added<br /> # and is not protected against padding oracle attacks.<br /> <br /> # --- DECRYPTION ---<br /> <br /> </span><span style="color: #0000BB">$ciphertext_dec </span><span style="color: #007700">= </span><span style="color: #0000BB">base64_decode</span><span style="color: #007700">(</span><span style="color: #0000BB">$ciphertext_base64</span><span style="color: #007700">);<br /> <br /> </span><span style="color: #FF8000"># retrieves the IV, iv_size should be created using mcrypt_get_iv_size()<br /> </span><span style="color: #0000BB">$iv_dec </span><span style="color: #007700">= </span><span style="color: #0000BB">substr</span><span style="color: #007700">(</span><span style="color: #0000BB">$ciphertext_dec</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">$iv_size</span><span style="color: #007700">);<br /> <br /> </span><span style="color: #FF8000"># retrieves the cipher text (everything except the $iv_size in the front)<br /> </span><span style="color: #0000BB">$ciphertext_dec </span><span style="color: #007700">= </span><span style="color: #0000BB">substr</span><span style="color: #007700">(</span><span style="color: #0000BB">$ciphertext_dec</span><span style="color: #007700">, </span><span style="color: #0000BB">$iv_size</span><span style="color: #007700">);<br /><br /> </span><span style="color: #FF8000"># may remove 00h valued characters from end of plain text<br /> </span><span style="color: #0000BB">$plaintext_dec </span><span style="color: #007700">= </span><span style="color: #0000BB">mcrypt_decrypt</span><span style="color: #007700">(</span><span style="color: #0000BB">MCRYPT_RIJNDAEL_128</span><span style="color: #007700">, </span><span style="color: #0000BB">$key</span><span style="color: #007700">,<br /> </span><span style="color: #0000BB">$ciphertext_dec</span><span style="color: #007700">, </span><span style="color: #0000BB">MCRYPT_MODE_CBC</span><span style="color: #007700">, </span><span style="color: #0000BB">$iv_dec</span><span style="color: #007700">);<br /> <br /> echo </span><span style="color: #0000BB">$plaintext_dec </span><span style="color: #007700">. </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
Key size: 32
ENJW8mS2KaJoNB5E5CoSAAu0xARgsR1bdzFWpEn+poYw45q+73az5kYi4j+0haevext1dGrcW8Qi59txfCBV8BBj3bzRP3dFCp3CPQSJ8eU=
This string was AES-256 / CBC / ZeroBytePadding encrypted.
</pre></div>
</div>
</div>
</p>
<p class="para">
See also <span class="function"><a href="function.mcrypt-module-open.html" class="function">mcrypt_module_open()</a></span> for a more advanced API
and an example.
</p>
</div>
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