Class Crypt_DES

Pure-PHP implementation of DES.

Package: Crypt\DES
Copyright: MMVII Jim Wigginton
License: MIT License
Author: Jim Wigginton <terrafrost@php.net>
Version: 0.1.0
Located at vendors/phpseclib/Crypt/DES.php

Methods summary

`public Crypt_DES`	# `Crypt_DES( optional $mode = CRYPT_MODE_DES_CBC )` Default Constructor. Default Constructor. Determines whether or not the mcrypt extension should be used. $mode should only, at present, be CRYPT_DES_MODE_ECB or CRYPT_DES_MODE_CBC. If not explictly set, CRYPT_DES_MODE_CBC will be used. Parameters `$mode` `optional` Integer $mode Returns `Crypt_DES`
`public`	# `setKey( String $key )` Sets the key. Sets the key. Keys can be of any length. DES, itself, uses 64-bit keys (eg. strlen($key) == 8), however, we only use the first eight, if $key has more then eight characters in it, and pad $key with the null byte if it is less then eight characters long. DES also requires that every eighth bit be a parity bit, however, we'll ignore that. If the key is not explicitly set, it'll be assumed to be all zero's. Parameters `$key` `String` $key
`public`	# `setPassword( String $password, optional $method = 'pbkdf2' )` Sets the password. Sets the password. Depending on what $method is set to, setPassword()'s (optional) parameters are as follows: pbkdf2: $hash, $salt, $count Parameters `$password` `String` $password `$method` `optional` String $method
`public`	# `setIV( String $iv )` Sets the initialization vector. (optional) Sets the initialization vector. (optional) SetIV is not required when CRYPT_DES_MODE_ECB is being used. If not explictly set, it'll be assumed to be all zero's. Parameters `$iv` `String` $iv
`public`	# `_generate_xor( Integer $length, String & $iv )` Generate CTR XOR encryption key Generate CTR XOR encryption key Encrypt the output of this and XOR it against the ciphertext / plaintext to get the plaintext / ciphertext in CTR mode. Parameters `$length` `Integer` $length `$iv` `String` $iv See `Crypt_DES::decrypt()` `Crypt_DES::encrypt()`
`public`	# `encrypt( String $plaintext )` Encrypts a message. Encrypts a message. $plaintext will be padded with up to 8 additional bytes. Other DES implementations may or may not pad in the same manner. Other common approaches to padding and the reasons why it's necessary are discussed in the following URL: http://www.di-mgt.com.au/cryptopad.html An alternative to padding is to, separately, send the length of the file. This is what SSH, in fact, does. strlen($plaintext) will still need to be a multiple of 8, however, arbitrary values can be added to make it that length. Parameters `$plaintext` `String` $plaintext See `Crypt_DES::decrypt()`
`public`	# `decrypt( String $ciphertext )` Decrypts a message. Decrypts a message. If strlen($ciphertext) is not a multiple of 8, null bytes will be added to the end of the string until it is. Parameters `$ciphertext` `String` $ciphertext See `Crypt_DES::encrypt()`
`public`	# `enableContinuousBuffer( )` Treat consecutive "packets" as if they are a continuous buffer. Treat consecutive "packets" as if they are a continuous buffer. Say you have a 16-byte plaintext $plaintext. Using the default behavior, the two following code snippets will yield different outputs: echo $des->encrypt(substr($plaintext, 0, 8)); echo $des->encrypt(substr($plaintext, 8, 8)); echo $des->encrypt($plaintext); The solution is to enable the continuous buffer. Although this will resolve the above discrepancy, it creates another, as demonstrated with the following: $des->encrypt(substr($plaintext, 0, 8)); echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8))); echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8))); 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_DES() 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. See `Crypt_DES::disableContinuousBuffer()`
`public`	# `disableContinuousBuffer( )` Treat consecutive packets as if they are a discontinuous buffer. Treat consecutive packets as if they are a discontinuous buffer. The default behavior. See `Crypt_DES::enableContinuousBuffer()`
`public`	# `enablePadding( )` Pad "packets". Pad "packets". DES works by encrypting eight bytes at a time. If you ever need to encrypt or decrypt something that's not a multiple of eight, it becomes necessary to pad the input so that it's length is a multiple of eight. Padding is enabled by default. Sometimes, however, it is undesirable to pad strings. Such is the case in SSH1, 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) See `Crypt_DES::disablePadding()`
`public`	# `disablePadding( )` Do not pad packets. Do not pad packets. See `Crypt_DES::enablePadding()`
`public`	# `_pad( mixed $text )` Pads a string Pads a string Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize (8). 8 - (strlen($text) & 7) bytes are added, each of which is equal to chr(8 - (strlen($text) & 7) 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. See `Crypt_DES::_unpad()`
`public`	# `_unpad( mixed $text )` Unpads a string 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. See `Crypt_DES::_pad()`
`public String`	# `_processBlock( String $block, Integer $mode )` Encrypts or decrypts a 64-bit block Encrypts or decrypts a 64-bit block $mode should be either CRYPT_DES_ENCRYPT or CRYPT_DES_DECRYPT. See Feistel.png to get a general idea of what this function does. Parameters `$block` `String` $block `$mode` `Integer` $mode Returns `String`
`public Array`	# `_prepareKey( String $key )` Creates the key schedule. Creates the key schedule. Parameters `$key` `String` $key Returns `Array`
`public String`	# `_string_shift( String & $string, optional $index = 1 )` String Shift String Shift Inspired by array_shift Parameters `$string` `String` $string `$index` `optional` Integer $index Returns `String`

Magic methods summary

Properties summary

`public Array`	`$keys`	# The Key Schedule The Key Schedule See `Crypt_DES::setKey()`
`public Integer`	`$mode`	# The Encryption Mode The Encryption Mode See `Crypt_DES::Crypt_DES()`
`public Boolean`	`$continuousBuffer`	# Continuous Buffer status Continuous Buffer status See `Crypt_DES::enableContinuousBuffer()`
`public Boolean`	`$padding`	# Padding status Padding status See `Crypt_DES::enablePadding()`
`public String`	`$iv`	# The Initialization Vector The Initialization Vector See `Crypt_DES::setIV()`
`public String`	`$encryptIV`	# A "sliding" Initialization Vector A "sliding" Initialization Vector See `Crypt_DES::enableContinuousBuffer()`
`public String`	`$decryptIV`	# A "sliding" Initialization Vector A "sliding" Initialization Vector See `Crypt_DES::enableContinuousBuffer()`
`public String`	`$enmcrypt`	# mcrypt resource for encryption mcrypt resource for encryption The mcrypt resource can be recreated every time something needs to be created or it can be created just once. Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode. See `Crypt_DES::encrypt()`
`public String`	`$demcrypt`	# mcrypt resource for decryption mcrypt resource for decryption The mcrypt resource can be recreated every time something needs to be created or it can be created just once. Since mcrypt operates in continuous mode, by default, it'll need to be recreated when in non-continuous mode. See `Crypt_DES::decrypt()`
`public Boolean`	`$enchanged`	# Does the enmcrypt resource need to be (re)initialized? Does the enmcrypt resource need to be (re)initialized? See `Crypt_DES::setKey()` `Crypt_DES::setIV()`
`public Boolean`	`$dechanged`	# Does the demcrypt resource need to be (re)initialized? Does the demcrypt resource need to be (re)initialized? See `Crypt_DES::setKey()` `Crypt_DES::setIV()`
`public Boolean`	`$paddable`	# Is the mode one that is paddable? Is the mode one that is paddable? See `Crypt_DES::Crypt_DES()`
`public String`	`$enbuffer`	# Encryption buffer for CTR, OFB and CFB modes Encryption buffer for CTR, OFB and CFB modes See `Crypt_DES::encrypt()`
`public String`	`$debuffer`	# Decryption buffer for CTR, OFB and CFB modes Decryption buffer for CTR, OFB and CFB modes See `Crypt_DES::decrypt()`
`public String`	`$ecb`	# mcrypt resource for CFB mode mcrypt resource for CFB mode See `Crypt_DES::encrypt()` `Crypt_DES::decrypt()`