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LV. Mcrypt Encryption FunctionsIntroduzione
This is an interface to the mcrypt library, which supports a wide
variety of block algorithms such as DES, TripleDES, Blowfish
(default), 3-WAY, SAFER-SK64, SAFER-SK128, TWOFISH, TEA, RC2 and
GOST in CBC, OFB, CFB and ECB cipher modes. Additionally, it
supports RC6 and IDEA which are considered "non-free".
Requisiti
These functions work using mcrypt.
To use it, download libmcrypt-x.x.tar.gz from http://mcrypt.sourceforge.net/ and follow the included installation
instructions. Windows users will find all the needed compiled mcrypt
binaries at http://ftp.emini.dk/pub/php/win32/mcrypt/.
If you linked against libmcrypt 2.4.x or higher, the following additional
block algorithms are supported: CAST, LOKI97, RIJNDAEL, SAFERPLUS,
SERPENT and the following stream ciphers: ENIGMA (crypt), PANAMA, RC4 and
WAKE. With libmcrypt 2.4.x or higher another cipher mode is also
available; nOFB.
Installazione
You need to compile PHP with the --with-mcrypt[=DIR] parameter to enable this
extension. DIR is the mcrypt install directory. Make sure you compile
libmcrypt with the option
--disable-posix-threads.
Configurazione di Runtime
Il comportamento di queste funzioni č influenzato dalle impostazioni di php.ini.
Tabella 1. Mcrypt configuration options | Name | Default | Changeable |
|---|
| mcrypt.algorithms_dir | NULL | PHP_INI_ALL | | mcrypt.modes_dir | NULL | PHP_INI_ALL |
For further details and definition of the PHP_INI_* constants see
ini_set().
Tipi di risorseQuesta estensione non definisce alcun tipo di risorsa. Costanti predefinite
Queste costanti sono definite da questa estensione e
sono disponibili solo se l'estensione č stata compilata
nel PHP o se č stata caricata dinamicamente a runtime.
Mcrypt can operate in four block cipher modes (CBC, OFB, CFB, and
ECB). If linked against libmcrypt-2.4.x or higher the functions can also operate
in the block cipher mode nOFB and in STREAM mode. Below you find a list
with all supported encryption modes together with the constants that are
defines for the encryption mode. For a more complete reference and
discussion see Applied Cryptography by Schneier (ISBN 0-471-11709-9).
MCRYPT_MODE_ECB (electronic codebook) is suitable for random data,
such as encrypting other keys. Since data there is short and random,
the disadvantages of ECB have a favorable negative effect.
MCRYPT_MODE_CBC (cipher block chaining) is especially suitable for
encrypting files where the security is increased over ECB
significantly.
MCRYPT_MODE_CFB (cipher feedback) is the best mode for encrypting byte
streams where single bytes must be encrypted.
MCRYPT_MODE_OFB (output feedback, in 8bit) is comparable to CFB, but
can be used in applications where error propagation cannot
be tolerated. It's insecure (because it operates in 8bit
mode) so it is not recommended to use it.
MCRYPT_MODE_NOFB (output feedback, in nbit) is comparable to OFB, but
more secure because it operates on the block size of the algorithm.
MCRYPT_MODE_STREAM is an extra mode to include some stream algorithms
like WAKE or RC4.
Some other mode and random device constants:
Mcrypt ciphers
Here is a list of ciphers which are currently supported by the mcrypt
extension. For a complete list of supported ciphers, see the defines at
the end of mcrypt.h. The general rule with the
mcrypt-2.2.x API is that you can access the cipher from PHP with
MCRYPT_ciphername. With the libmcrypt-2.4.x and libmcrypt-2.5.x API these constants also work,
but it is possible to specify the name of the cipher as a string with a
call to mcrypt_module_open().
MCRYPT_3DES MCRYPT_ARCFOUR_IV (libmcrypt > 2.4.x only) MCRYPT_ARCFOUR (libmcrypt > 2.4.x only) MCRYPT_BLOWFISH MCRYPT_CAST_128 MCRYPT_CAST_256 MCRYPT_CRYPT MCRYPT_DES MCRYPT_DES_COMPAT (libmcrypt 2.2.x only) MCRYPT_ENIGMA (libmcrypt > 2.4.x only, alias for MCRYPT_CRYPT) MCRYPT_GOST MCRYPT_IDEA (non-free) MCRYPT_LOKI97 (libmcrypt > 2.4.x only) MCRYPT_MARS (libmcrypt > 2.4.x only, non-free) MCRYPT_PANAMA (libmcrypt > 2.4.x only) MCRYPT_RIJNDAEL_128 (libmcrypt > 2.4.x only) MCRYPT_RIJNDAEL_192 (libmcrypt > 2.4.x only) MCRYPT_RIJNDAEL_256 (libmcrypt > 2.4.x only) MCRYPT_RC2 MCRYPT_RC4 (libmcrypt 2.2.x only) MCRYPT_RC6 (libmcrypt > 2.4.x only) MCRYPT_RC6_128 (libmcrypt 2.2.x only) MCRYPT_RC6_192 (libmcrypt 2.2.x only) MCRYPT_RC6_256 (libmcrypt 2.2.x only) MCRYPT_SAFER64 MCRYPT_SAFER128 MCRYPT_SAFERPLUS (libmcrypt > 2.4.x only) MCRYPT_SERPENT(libmcrypt > 2.4.x only) MCRYPT_SERPENT_128 (libmcrypt 2.2.x only) MCRYPT_SERPENT_192 (libmcrypt 2.2.x only) MCRYPT_SERPENT_256 (libmcrypt 2.2.x only) MCRYPT_SKIPJACK (libmcrypt > 2.4.x only) MCRYPT_TEAN (libmcrypt 2.2.x only) MCRYPT_THREEWAY MCRYPT_TRIPLEDES (libmcrypt > 2.4.x only) MCRYPT_TWOFISH (for older mcrypt 2.x versions, or mcrypt > 2.4.x ) MCRYPT_TWOFISH128 (TWOFISHxxx are available in newer 2.x versions, but not in the 2.4.x versions) MCRYPT_TWOFISH192 MCRYPT_TWOFISH256 MCRYPT_WAKE (libmcrypt > 2.4.x only) MCRYPT_XTEA (libmcrypt > 2.4.x only)
You must (in CFB and OFB mode) or can (in CBC mode) supply an
initialization vector (IV) to the respective cipher function. The
IV must be unique and must be the same when
decrypting/encrypting. With data which is stored encrypted, you
can take the output of a function of the index under which the
data is stored (e.g. the MD5 key of the filename).
Alternatively, you can transmit the IV together with the encrypted
data (see chapter 9.3 of Applied Cryptography by Schneier (ISBN 0-471-11709-9) for a
discussion of this topic).
Esempi
Mcrypt can be used to encrypt and decrypt using the above
mentioned ciphers. If you linked against libmcrypt-2.2.x, the
four important mcrypt commands (mcrypt_cfb(),
mcrypt_cbc(), mcrypt_ecb(),
and mcrypt_ofb()) can operate in both modes
which are named MCRYPT_ENCRYPT and MCRYPT_DECRYPT, respectively.
Esempio 1. Encrypt an input value with TripleDES under 2.2.x in ECB mode |
<?php
$key = "this is a secret key";
$input = "Let us meet at 9 o'clock at the secret place.";
$encrypted_data = mcrypt_ecb (MCRYPT_3DES, $key, $input, MCRYPT_ENCRYPT);
?>
|
|
This example will give you the encrypted data as a string in
$encrypted_data.
If you linked against libmcrypt 2.4.x or 2.5.x, these functions are still
available, but it is recommended that you use the advanced functions.
Esempio 2. Encrypt an input value with TripleDES under 2.4.x and higher in ECB mode |
<?php
$key = "this is a secret key";
$input = "Let us meet at 9 o'clock at the secret place.";
$td = mcrypt_module_open('tripledes', '', 'ecb', '');
$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
mcrypt_generic_init($td, $key, $iv);
$encrypted_data = mcrypt_generic($td, $input);
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
?>
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This example will give you the encrypted data as a string in
$encrypted_data. For a full example see
mcrypt_module_open().
 add a note
User Contributed Notes
Mcrypt Encryption Functions
dzelko at hotmail dot com
14-May-2004 06:11
Windows IIS Users - Problems installing/using mcrypt and other extensions
::
I've noticed a lot of users complaining in forums that they have difficult time getting mcrypt extension to function/ finding or installing working .dlls when using IIS:
::
Easy solution that works well for me: (IIS 6 on Win 2003 Svr and IIS on XP Pro) #customized install later for increased security#
1. Install current stable php version using windows installer #gets php up and running quickly#
2. Download Windows Binary Package
3. Extract Package Library to PHP folder installer generates - overwrite all
4. Edit php.ini as appropriate. (specifically for mcrypt uncomment mcrypt=php_mcrypt.dll)
::
No mo' problems.
Deek Starr
21-Apr-2004 09:16
As per the issue with decrypting (mdecrypt_generic) on iss in windows. My finding as that the new 2004 version works but the 2002 does not.
I'm using WinXP Server 2003 - ISS 6.0 with:
libmcrypt.dll 19-Jan-2004 02:27 163k
http://ftp.emini.dk/pub/php/win32/mcrypt/libmcrypt.dll
php_mycrypt.dll 14-Jan-2004 5:34 36.8k
From the v4.3.6 windows zip distribution of php.
http://www.php.net/get/php-4.3.6-Win32.zip/from/a/mirror
My assumption is that the new IIS 6 should use the new libmcrypt where IIS <= 5 should use the older version.
[ Hope that helps ]
dmichel at earthlink dot net
14-Apr-2004 04:34
Jonathon Freeman
17-Mar-2004 07:00
If you're a Windows user you might be having trouble getting Mcrypt up and going. This is what I did, and it worked perfectly:
1. Download the latest binaries from http://ftp.proventum.net/pub/php/win32/misc/mcrypt/. At the the time of this writing, the link at the top of this page doesn't have everything you need.
2. Unzip the file, then follow the instructions in README.txt.
3. Restart Apache, and viola!
Hope that helps someone...
robert at peakepro dot com
02-Mar-2004 08:59
I have ammended the mcrypt_check_sanity() function. This is a bug fix: the function was reinitializing the IV, which is unacceptable. Here is the complete, fixed version. Note that 'stream' mode is not tested.
<?PHP
function mcrypt_check_sanity() {
$modes = mcrypt_list_modes();
$algorithms = mcrypt_list_algorithms();
foreach ($algorithms as $cipher) {
if(mcrypt_module_self_test($cipher)) {
print $cipher." ok.<br />\n";
} else {
print $cipher." not ok.<br />\n";
}
foreach ($modes as $mode) {
if($mode == 'stream') {
$result = "not tested";
} else if(mcrypt_test_module_mode($cipher,$mode)) {
$result = "ok";
} else {
$result = "not ok";
}
print $cipher." in mode ".$mode." ".$result."<br />\n";
mcrypt_module_close($td);
}
}
}
function mcrypt_test_module_mode($module,$mode) {
$key = 'this is a very long key, even too long for the cipher';
$plain_text = 'very important data';
$td = mcrypt_module_open($module, '',$mode, '');
$key = substr($key, 0, mcrypt_enc_get_key_size($td));
$iv_size = mcrypt_enc_get_iv_size($td);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
if (mcrypt_generic_init($td, $key, $iv) != -1) {
$c_t = mcrypt_generic($td, $plain_text);
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
$td = mcrypt_module_open($module, '', $mode, '');
$key = substr($key, 0, mcrypt_enc_get_key_size($td));
mcrypt_generic_init($td, $key, $iv);
$p_t = trim(mdecrypt_generic($td, $c_t)); mcrypt_generic_end($td);
mcrypt_module_close($td);
}
if (strncmp($p_t, $plain_text, strlen($plain_text)) == 0) {
return TRUE;
} else {
return FALSE;
}
}
mcrypt_check_sanity();
?>
Apologies for any confusion the previous version may have caused. The only working mode listed was ecb, since it does not use an IV.
robert at peakepro dot com
15-Feb-2004 03:17
I found this nested loop very useful for checking the sanity of my libmcrypt install. It turned out many of the modules weren't working in certain modes. Hopefully this will save someone some frustration:
<?php
function mcrypt_check_sanity() {
$modes = mcrypt_list_modes();
$algorithms = mcrypt_list_algorithms();
foreach ($algorithms as $cipher) {
if(mcrypt_module_self_test($cipher)) {
print $cipher." ok.<br />\n";
} else {
print $cipher." not ok.<br />\n";
}
foreach ($modes as $mode) {
if(mcrypt_test_module_mode($cipher,$mode)) {
$result = "ok";
} else {
$result = "not ok";
}
print $cipher." in mode ".$mode." ".$result."<br />\n";
mcrypt_module_close($td);
}
}
}
function mcrypt_test_module_mode($module,$mode) {
$key = 'this is a very long key, even too long for the cipher';
$plain_text = 'very important data';
$td = mcrypt_module_open($module, '',$mode, '');
$key = substr($key, 0, mcrypt_enc_get_key_size($td));
$iv_size = mcrypt_enc_get_iv_size($td);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
if (mcrypt_generic_init($td, $key, $iv) != -1) {
$c_t = mcrypt_generic($td, $plain_text);
mcrypt_generic_end($td);
mcrypt_module_close($td);
$td = mcrypt_module_open($module, '', $mode, '');
$key = substr($key, 0, mcrypt_enc_get_key_size($td));
$iv_size = mcrypt_enc_get_iv_size($td);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
mcrypt_generic_init($td, $key, $iv);
$p_t = mdecrypt_generic($td, $c_t);
mcrypt_generic_end($td);
mcrypt_module_close($td);
}
if (strncmp($p_t, $plain_text, strlen($plain_text)) == 0) {
return TRUE;
} else {
return FALSE;
}
}
?>
mp at ecetra dot com
02-Feb-2004 11:35
i rebuilded php from sources today, the distribution was redhat el es 3. first i missed libltdl as mentioned in comment from groundzero, but the redhat has propably changed the rpm content, cause i needed libtool (libtool-lib was already installed, but was not enough). second '--disable-posix-threads' was not required: i am wondering why everybody ask for this, because i never used it and it always worked fine.
kr,
-misk
groundzero at zuavra dot net
09-Jan-2004 11:08
If you've ever compiled PHP from source (any version) you may be familiar with the [in]famous MCRYPT_BLOWFISH_128 compilation error that appears when you attempt to compile --with-mcrypt. It occurs often on Debian but not only there. The problem: during compilation, the PHP configure script always assumes that libmcrypt has been built in conjunction with libltdl. Whenever that is not the case, PHP compilation will fail later saying certain headers (such as the above blowfish example) are missing from mcrypt.h (which is misleading, they're not supposed to be there nor looked after if libltdl was properly involved). Solution: make sure your libmcrypt was linked against libltdl before you even start configuring PHP. You can check by running 'ldd lybmcrypt.so' and verifying that libltdl appears in the output. libltdl can be found in libltld[3][-dev] on Debian or in libtool-libs on Red Hat.
simms
03-Oct-2003 08:03
DEBIAN users: avoid mcrypt installation headaches.
to add mcrypt support to an existing php installation, get root and run
apt-get install php4-mcrypt
restart your webserver, and voilą.
steve@itemfront dot ltd dot uk
29-Sep-2003 11:17
Just spent a while getting mcrypt support working with php. Used libmcrypt version 2.5.7 with php 4.3.3. Out of the box it just won't work. Configure as follows:
libmcrypt:
./configure --disable-posix-threads --enable-dynamic-loading
php: ( as you can see, it's built for a SunONE server, but that's the easy bit to configure! )
./configure --with-nsapi=/usr/iplanet/servers --enable-sigchld --with-ldap --with-zlib-dir=/usr/lib --with-mcrypt=<srcdir>/libmcrypt-2.5.7
hth, steve
herowekker at hotmail dot com
31-Jul-2003 11:55
mcrypt_ecb with base64_decode gave some problems, i found out that it had to be chopped to work:
chop(mcrypt_ecb(MCRYPT_BLOWFISH,$key,base64_decode
($input),MCRYPT_DECRYPT));
paul at xmill dot com
05-Nov-2002 04:25
The statement that use of the 'generic' functions is 'recommended' in 2.4+ should probably be 'required'. Having like many others struggled with a "mcrypt module initialization failed" error even when phpinfo() showed mcrypt installed and all its algorithms loaded, I found that:
$key = mcrypt_ecb (MCRYPT_3DES, $magic, $input, MCRYPT_ENCRYPT);
fails, but
$td = mcrypt_module_open (MCRYPT_TripleDES, "", MCRYPT_MODE_ECB, "");
$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size ($td), MCRYPT_RAND);
mcrypt_generic_init ($td, $magic, $iv);
$key = mcrypt_generic ($td, $input);
mcrypt_generic_end ($td);
works fine. You can't leave out the creation of the IV to the right length, even though ECB doesn't use it (happily, because I want it repeatable).
scott at boothcreek dot com
28-Mar-2002 07:28
If you are using ECB mode to encrypt it does not seem to use the iv (initialization vector) for much of anything, given the same key it will always decrypt it no matter what the iv is. If you use CBC mode you must decrypt with the same iv that you encrypted with.
If you use a different iv before decrypting, your decrypt will not work. IMHO it seems better to use CBC mode than ECB as ECB will always encrypt to the same cipher text given the same plain text (leaving you open to know plaintext attacks). CBC uses the random iv which means text encrypts to different things. You probably could get the same effect from using random keys in ECB mode.
Read that in the Schneier book - Applied Cryptography (ISBN 0-471-11709-9) This book is a must for anyone seriously using any type of encryption.
pawelNOSPAM at rsc dot pl
03-Aug-2001 12:37
If you compiled mcrypt and php without problem, but phpinfo() shows there are no supported ciphers and modes, try to change mode to 755 on libdirs (/usr/local/libmcrypt, /usr/local/libcrypt).
mountie at paygate dot net
10-Feb-2000 11:21
the encrypted result data maybe binary data and It make errors in sql query.
so use the base64_encode/base64_decode function with mcrypt()
try below
base64_encode(mcrypt_ecb(MCRYPT_BLOWFISH,$key,$input,MCRYPT_ENCRYPT));
mcrypt_ecb(MCRYPT_BLOWFISH,$key,base64_decode($input),MCRYPT_DECRYPT);
nsayer at quack dot kfu dot com
30-Jun-1999 01:31
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