lib/3rdParty/phpseclib/Crypt/Rijndael.php

Properties

Description

Pure-PHP implementation of Rijndael.

Does not use mcrypt, even when available, for reasons that are explained below. PHP versions 4 and 5 If {@link Crypt_Rijndael::setBlockLength() setBlockLength()} isn't called, it'll be assumed to be 128 bits. If {@link Crypt_Rijndael::setKeyLength() setKeyLength()} isn't called, it'll be calculated from {@link Crypt_Rijndael::setKey() setKey()}. ie. if the key is 128-bits, the key length will be 128-bits. If it's 136-bits it'll be null-padded to 160-bits and 160 bits will be the key length until {@link Crypt_Rijndael::setKey() setKey()} is called, again, at which point, it'll be recalculated. Not all Rijndael implementations may support 160-bits or 224-bits as the block length / key length. mcrypt, for example, does not. AES, itself, only supports block lengths of 128 and key lengths of 128, 192, and 256. {@link http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=10 Rijndael-ammended.pdf#page=10} defines the algorithm for block lengths of 192 and 256 but not for block lengths / key lengths of 160 and 224. Indeed, 160 and 224 are first defined as valid key / block lengths in {@link http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf#page=44 Rijndael-ammended.pdf#page=44}: Extensions: Other block and Cipher Key lengths. {@internal The variable names are the same as those in {@link http://www.csrc.nist.gov/publications/fips/fips197/fips-197.pdf#page=10 fips-197.pdf#page=10}.}} Here's a short example of how to use this library: setKey('abcdefghijklmnop'); $size = 10 * 1024; $plaintext = ''; for ($i = 0; $i < $size; $i++) { $plaintext.= 'a'; } echo $rijndael->decrypt($rijndael->encrypt($plaintext)); ?> LICENSE: Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Constants

  CRYPT_RIJNDAEL_MODE_CTR = -1

Encrypt / decrypt using the Counter mode.
Set to -1 since that's what Crypt/Random.php uses to index the CTR mode.

  CRYPT_RIJNDAEL_MODE_ECB = 1

Encrypt / decrypt using the Electronic Code Book mode.


  CRYPT_RIJNDAEL_MODE_CBC = 2

Encrypt / decrypt using the Code Book Chaining mode.


  CRYPT_RIJNDAEL_MODE_CFB = 3

Encrypt / decrypt using the Cipher Feedback mode.


  CRYPT_RIJNDAEL_MODE_OFB = 4

Encrypt / decrypt using the Cipher Feedback mode.


  CRYPT_RIJNDAEL_MODE_INTERNAL = 1

Toggles the internal implementation


  CRYPT_RIJNDAEL_MODE_MCRYPT = 2

Toggles the mcrypt implementation


Classes

Crypt_Rijndael

Properties

 
 
public  
 
No 
No 

Description

Pure-PHP implementation of Rijndael.

Methods

Crypt_Rijndael, _decryptBlock, _encryptBlock, _generate_xor, _invSubWord, _pad, _setup, _string_shift, _subWord, _unpad, decrypt, disableContinuousBuffer, disablePadding, enableContinuousBuffer, enablePadding, encrypt, setBlockLength, setIV, setKey, setKeyLength,

Crypt_Rijndael(   $mode = CRYPT_RIJNDAEL_MODE_CBC, ) : \Crypt_Rijndael

Description

Default Constructor.
Determines whether or not the mcrypt extension should be used. $mode should only, at present, be CRYPT_RIJNDAEL_MODE_ECB or CRYPT_RIJNDAEL_MODE_CBC. If not explictly set, CRYPT_RIJNDAEL_MODE_CBC will be used.

Arguments

Name Type Description Default
$mode n/a CRYPT_RIJNDAEL_MODE_CBC

Return value

Type Description
\Crypt_Rijndael

Tags

Name Description
access public

_decryptBlock( String   $in, ) : String

Description

Decrypts a block

Arguments

Name Type Description Default
$in String

Return value

Type Description
String

Tags

Name Description
access private

_encryptBlock( String   $in, ) : String

Description

Encrypts a block

Arguments

Name Type Description Default
$in String

Return value

Type Description
String

Tags

Name Description
access private

_generate_xor( Integer   $length, String   $iv, ) : n/a

Description

Generate CTR XOR encryption key
Encrypt the output of this and XOR it against the ciphertext / plaintext to get the plaintext / ciphertext in CTR mode.

Arguments

Name Type Description Default
$length Integer
$iv String

Return value

Type Description
n/a n/a

Tags

Name Description
see
see
access public

_invSubWord(   $word, ) : n/a

Description

Performs inverse S-Box substitutions

Arguments

Name Type Description Default
$word n/a

Return value

Type Description
n/a n/a

Tags

Name Description
access private

_pad(   $text, ) : n/a

Description

Pads a string
Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize. $block_size - (strlen($text) % $block_size) bytes are added, each of which is equal to chr($block_size - (strlen($text) % $block_size) If padding is disabled and $text is not a multiple of the blocksize, the string will be padded regardless and padding will, hence forth, be enabled.

Arguments

Name Type Description Default
$text n/a

Return value

Type Description
n/a n/a

Tags

Name Description
see
access private

_setup( ) : n/a

Description

Setup Rijndael
Validates all the variables and calculates $Nr - the number of rounds that need to be performed - and $w - the key key schedule.

Return value

Type Description
n/a n/a

Tags

Name Description
access private

_string_shift( String   $string,   $index = 1, ) : String

Description

String Shift
Inspired by array_shift

Arguments

Name Type Description Default
$string String
$index n/a 1

Return value

Type Description
String

Tags

Name Description
access private

_subWord(   $word, ) : n/a

Description

Performs S-Box substitutions

Arguments

Name Type Description Default
$word n/a

Return value

Type Description
n/a n/a

Tags

Name Description
access private

_unpad(   $text, ) : n/a

Description

Unpads a string.
If padding is enabled and the reported padding length is invalid the encryption key will be assumed to be wrong and false will be returned.

Arguments

Name Type Description Default
$text n/a

Return value

Type Description
n/a n/a

Tags

Name Description
see
access private

decrypt( String   $ciphertext, ) : n/a

Description

Decrypts a message.
If strlen($ciphertext) is not a multiple of the block size, null bytes will be added to the end of the string until it is.

Arguments

Name Type Description Default
$ciphertext String

Return value

Type Description
n/a n/a

Tags

Name Description
see
access public

disableContinuousBuffer( ) : n/a

Description

Treat consecutive packets as if they are a discontinuous buffer.
The default behavior.

Return value

Type Description
n/a n/a

Tags

Name Description
see
access public

disablePadding( ) : n/a

Description

Do not pad packets.

Return value

Type Description
n/a n/a

Tags

Name Description
see
access public

enableContinuousBuffer( ) : n/a

Description

Treat consecutive "packets" as if they are a continuous buffer.
Say you have a 32-byte plaintext $plaintext. Using the default behavior, the two following code snippets will yield different outputs: echo $rijndael->encrypt(substr($plaintext, 0, 16)); echo $rijndael->encrypt(substr($plaintext, 16, 16)); echo $rijndael->encrypt($plaintext); The solution is to enable the continuous buffer. Although this will resolve the above discrepancy, it creates another, as demonstrated with the following: $rijndael->encrypt(substr($plaintext, 0, 16)); echo $rijndael->decrypt($des->encrypt(substr($plaintext, 16, 16))); echo $rijndael->decrypt($des->encrypt(substr($plaintext, 16, 16))); With the continuous buffer disabled, these would yield the same output. With it enabled, they yield different outputs. The reason is due to the fact that the initialization vector's change after every encryption / decryption round when the continuous buffer is enabled. When it's disabled, they remain constant. Put another way, when the continuous buffer is enabled, the state of the Crypt_Rijndael() object changes after each encryption / decryption round, whereas otherwise, it'd remain constant. For this reason, it's recommended that continuous buffers not be used. They do offer better security and are, in fact, sometimes required (SSH uses them), however, they are also less intuitive and more likely to cause you problems.

Return value

Type Description
n/a n/a

Tags

Name Description
see
access public

enablePadding( ) : n/a

Description

Pad "packets".
Rijndael works by encrypting between sixteen and thirty-two bytes at a time, provided that number is also a multiple of four. If you ever need to encrypt or decrypt something that isn't of the proper length, it becomes necessary to pad the input so that it is of the proper length. Padding is enabled by default. Sometimes, however, it is undesirable to pad strings. Such is the case in SSH, where "packets" are padded with random bytes before being encrypted. Unpad these packets and you risk stripping away characters that shouldn't be stripped away. (SSH knows how many bytes are added because the length is transmitted separately)

Return value

Type Description
n/a n/a

Tags

Name Description
see
access public

encrypt( String   $plaintext, ) : n/a

Description

Encrypts a message.
$plaintext will be padded with additional bytes such that it's length is a multiple of the block size. Other Rjindael implementations may or may not pad in the same manner. Other common approaches to padding and the reasons why it's necessary are discussed in the following URL: {@link http://www.di-mgt.com.au/cryptopad.html http://www.di-mgt.com.au/cryptopad.html} An alternative to padding is to, separately, send the length of the file. This is what SSH, in fact, does. strlen($plaintext) will still need to be a multiple of 8, however, arbitrary values can be added to make it that length.

Arguments

Name Type Description Default
$plaintext String

Return value

Type Description
n/a n/a

Tags

Name Description
see
access public

setBlockLength( Integer   $length, ) : n/a

Description

Sets the block length
Valid block lengths are 128, 160, 192, 224, and 256. If the length is less than 128, it will be rounded up to 128. If the length is greater then 128 and invalid, it will be rounded down to the closest valid amount.

Arguments

Name Type Description Default
$length Integer

Return value

Type Description
n/a n/a

Tags

Name Description
access public

setIV( String   $iv, ) : n/a

Description

Sets the initialization vector. (optional)
SetIV is not required when CRYPT_RIJNDAEL_MODE_ECB is being used. If not explictly set, it'll be assumed to be all zero's.

Arguments

Name Type Description Default
$iv String

Return value

Type Description
n/a n/a

Tags

Name Description
access public

setKey( String   $key, ) : n/a

Description

Sets the key.
Keys can be of any length. Rijndael, itself, requires the use of a key that's between 128-bits and 256-bits long and whose length is a multiple of 32. If the key is less than 256-bits and the key length isn't set, we round the length up to the closest valid key length, padding $key with null bytes. If the key is more than 256-bits, we trim the excess bits. If the key is not explicitly set, it'll be assumed to be all null bytes.

Arguments

Name Type Description Default
$key String

Return value

Type Description
n/a n/a

Tags

Name Description
access public

setKeyLength( Integer   $length, ) : n/a

Description

Sets the key length
Valid key lengths are 128, 160, 192, 224, and 256. If the length is less than 128, it will be rounded up to 128. If the length is greater then 128 and invalid, it will be rounded down to the closest valid amount.

Arguments

Name Type Description Default
$length Integer

Return value

Type Description
n/a n/a

Tags

Name Description
access public

Properties

$c, $changed, $continuousBuffer, $debuffer, $decryptIV, $dt0, $dt1, $dt2, $dt3, $dw, $enbuffer, $encryptIV, $explicit_key_length, $iv, $key, $mode, $paddable, $padding, $t0, $t1, $t2, $t3, $w,

Array  public  $c =

Shift offsets


Boolean  public  $changed = true

Does the key schedule need to be (re)calculated?


Boolean  public  $continuousBuffer = false

Continuous Buffer status


String  public  $debuffer = array('ciphertext' => '')

Decryption buffer for CTR, OFB and CFB modes


String  public  $decryptIV = ''

A "sliding" Initialization Vector


Array  public  $dt0 =

Precomputed invMixColumns table


Array  public  $dt1 =

Precomputed invMixColumns table


Array  public  $dt2 =

Precomputed invMixColumns table


Array  public  $dt3 =

Precomputed invMixColumns table


Array  public  $dw =

The Inverse Key Schedule


String  public  $enbuffer = array('encrypted' => '', 'xor' => '')

Encryption buffer for CTR, OFB and CFB modes


String  public  $encryptIV = ''

A "sliding" Initialization Vector


Boolean  public  $explicit_key_length = false

Has the key length explicitly been set or should it be derived from the key, itself?


String  public  $iv = ''

The Initialization Vector


String  public  $key = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"

The Key


Integer  public  $mode =

The Encryption Mode


Boolean  public  $paddable = false

Is the mode one that is paddable?


Boolean  public  $padding = true

Padding status


Array  public  $t0 =

Precomputed mixColumns table


Array  public  $t1 =

Precomputed mixColumns table


Array  public  $t2 =

Precomputed mixColumns table


Array  public  $t3 =

Precomputed mixColumns table


Array  public  $w =

The Key Schedule


Documentation was generated by phpDocumentor 2.0.1 .

Namespaces

  • global

    Packages