Class Crypt_RC4

Pure-PHP implementation of RC4.

Package: Crypt\RC4
Copyright: MMVII Jim Wigginton
License: MIT License
Author: Jim Wigginton <terrafrost@php.net>
Version: 0.1.0
Located at vendors/phpseclib/Crypt/RC4.php

Methods summary

`public Crypt_RC4`	# `Crypt_RC4( )` Default Constructor. Default Constructor. Determines whether or not the mcrypt extension should be used. Returns `Crypt_RC4`
`public`	# `setKey( String $key )` Sets the key. Sets the key. Keys can be between 1 and 256 bytes long. If they are longer then 256 bytes, the first 256 bytes will be used. If no key is explicitly set, it'll be assumed to be a single null byte. Parameters `$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, $dkLen Parameters `$password` `String` $password `$method` `optional` String $method
`public`	# `setIV( String $iv )` Dummy function. Dummy function. Some protocols, such as WEP, prepend an "initialization vector" to the key, effectively creating a new key [1]. If you need to use an initialization vector in this manner, feel free to prepend it to the key, yourself, before calling setKey(). [1] WEP's initialization vectors (IV's) are used in a somewhat insecure way. Since, in that protocol, the IV's are relatively easy to predict, an attack described by Scott Fluhrer, Itsik Mantin, and Adi Shamir can be used to quickly guess at the rest of the key. The following links elaborate: http://www.rsa.com/rsalabs/node.asp?id=2009 http://en.wikipedia.org/wiki/Related_key_attack Parameters `$iv` `String` $iv See `Crypt_RC4::setKey()`
`public`	# `encrypt( String $plaintext )` Encrypts a message. Encrypts a message. Parameters `$plaintext` `String` $plaintext See `Crypt_RC4::_crypt()`
`public`	# `decrypt( String $ciphertext )` Decrypts a message. Decrypts a message. $this->decrypt($this->encrypt($plaintext)) == $this->encrypt($this->encrypt($plaintext)). Atleast if the continuous buffer is disabled. Parameters `$ciphertext` `String` $ciphertext See `Crypt_RC4::_crypt()`
`public`	# `_crypt( String $text, Integer $mode )` Encrypts or decrypts a message. Encrypts or decrypts a message. Parameters `$text` `String` $text `$mode` `Integer` $mode See `Crypt_RC4::encrypt()` `Crypt_RC4::decrypt()`
`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 $rc4->encrypt(substr($plaintext, 0, 8)); echo $rc4->encrypt(substr($plaintext, 8, 8)); echo $rc4->encrypt($plaintext); The solution is to enable the continuous buffer. Although this will resolve the above discrepancy, it creates another, as demonstrated with the following: $rc4->encrypt(substr($plaintext, 0, 8)); echo $rc4->decrypt($des->encrypt(substr($plaintext, 8, 8))); echo $rc4->decrypt($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_RC4::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_RC4::enableContinuousBuffer()`
`public`	# `enablePadding( )` Dummy function. Dummy function. Since RC4 is a stream cipher and not a block cipher, no padding is necessary. The only reason this function is included is so that you can switch between a block cipher and a stream cipher transparently. See `Crypt_RC4::disablePadding()`
`public`	# `disablePadding( )` Dummy function. Dummy function. See `Crypt_RC4::enablePadding()`
`public`	# `__destruct( )` Class destructor. Class destructor. Will be called, automatically, if you're using PHP5. If you're using PHP4, call it yourself. Only really needs to be called if mcrypt is being used.
`public`	# `_closeMCrypt( )` Properly close the MCrypt objects. Properly close the MCrypt objects.

Magic methods summary

Properties summary

`public String`	`$key`	# The Key The Key See `Crypt_RC4::setKey()`
`public Array`	`$encryptStream`	# The Key Stream for encryption The Key Stream for encryption If CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT, this will be equal to the mcrypt object See `Crypt_RC4::setKey()`
`public Array`	`$decryptStream`	# The Key Stream for decryption The Key Stream for decryption If CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT, this will be equal to the mcrypt object See `Crypt_RC4::setKey()`
`public Integer`	`$encryptIndex`	# The $i and $j indexes for encryption The $i and $j indexes for encryption See `Crypt_RC4::_crypt()`
`public Integer`	`$decryptIndex`	# The $i and $j indexes for decryption The $i and $j indexes for decryption See `Crypt_RC4::_crypt()`
`public Integer`	`$mode`	# The Encryption Algorithm The Encryption Algorithm Only used if CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT. Only possible values are MCRYPT_RC4 or MCRYPT_ARCFOUR. See `Crypt_RC4::Crypt_RC4()`
`public Boolean`	`$continuousBuffer`	# Continuous Buffer status Continuous Buffer status See `Crypt_RC4::enableContinuousBuffer()`