class RC2 extends Base (View source)

Pure-PHP implementation of RC2.

Constants

MODE_CTR

Encrypt / decrypt using the Counter mode.

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

MODE_ECB

Encrypt / decrypt using the Electronic Code Book mode.

MODE_CBC

Encrypt / decrypt using the Code Book Chaining mode.

MODE_CFB

Encrypt / decrypt using the Cipher Feedback mode.

MODE_CFB8

Encrypt / decrypt using the Cipher Feedback mode (8bit)

MODE_OFB

Encrypt / decrypt using the Output Feedback mode.

MODE_STREAM

Encrypt / decrypt using streaming mode.

ENGINE_INTERNAL

Base value for the internal implementation $engine switch

ENGINE_MCRYPT

Base value for the mcrypt implementation $engine switch

ENGINE_OPENSSL

Base value for the mcrypt implementation $engine switch

Properties

static bool $WHIRLPOOL_AVAILABLE Whirlpool available flag from  Base
int $mode The Encryption Mode from  Base
int $block_size Block Length of the cipher
string $key The Key
string $iv The Initialization Vector from  Base
string $encryptIV A "sliding" Initialization Vector from  Base
string $decryptIV A "sliding" Initialization Vector from  Base
bool $continuousBuffer Continuous Buffer status from  Base
array $enbuffer Encryption buffer for CTR, OFB and CFB modes from  Base
array $debuffer Decryption buffer for CTR, OFB and CFB modes from  Base
resource $enmcrypt mcrypt resource for encryption from  Base
resource $demcrypt mcrypt resource for decryption from  Base
bool $enchanged Does the enmcrypt resource need to be (re)initialized? from  Base
bool $dechanged Does the demcrypt resource need to be (re)initialized? from  Base
resource $ecb mcrypt resource for CFB mode from  Base
int $cfb_init_len Optimizing value while CFB-encrypting
bool $changed Does internal cipher state need to be (re)initialized? from  Base
bool $padding Padding status from  Base
bool $paddable Is the mode one that is paddable? from  Base
int $engine Holds which crypt engine internaly should be use, which will be determined automatically on __construct() from  Base
int $preferredEngine Holds the preferred crypt engine from  Base
string $cipher_name_mcrypt The mcrypt specific name of the cipher
string $cipher_name_openssl The openssl specific name of the cipher from  Base
string $cipher_name_openssl_ecb The openssl specific name of the cipher in ECB mode from  Base
string $password_default_salt The default salt used by setPassword() from  Base
callable $inline_crypt The name of the performance-optimized callback function from  Base
mixed $use_inline_crypt Holds whether performance-optimized $inline_crypt() can/should be used. from  Base
bool $openssl_emulate_ctr If OpenSSL can be used in ECB but not in CTR we can emulate CTR from  Base
mixed $openssl_options Determines what options are passed to openssl_encrypt/decrypt from  Base
bool $explicit_key_length Has the key length explicitly been set or should it be derived from the key, itself? from  Base
bool $skip_key_adjustment Don't truncate / null pad key
string $orig_key The Original (unpadded) Key
int $key_length Key Length (in bytes)
int $default_key_length The key length in bits.
int $current_key_length The key length in bits.
array $keys The Key Schedule
array $pitable Key expansion randomization table.
array $invpitable Inverse key expansion randomization table.

Methods

__construct(int $mode = self::MODE_CBC)

Default Constructor.

from  Base
setIV(string $iv)

Sets the initialization vector. (optional)

from  Base
setKeyLength(int $length)

Sets the key length.

int
getKeyLength()

Returns the current key length

int
getBlockLength()

Returns the current block length in bits

from  Base
setKey(string $key, int $t1 = 0)

Sets the key.

bool
setPassword(string $password, string $method = 'pbkdf2')

Sets the password.

from  Base
string
encrypt(string $plaintext)

Encrypts a message.

string
decrypt(string $ciphertext)

Decrypts a message.

string
_openssl_ctr_process(string $plaintext, string $encryptIV, array $buffer)

OpenSSL CTR Processor

from  Base
string
_openssl_ofb_process(string $plaintext, string $encryptIV, array $buffer)

OpenSSL OFB Processor

from  Base
int
_openssl_translate_mode()

phpseclib <-> OpenSSL Mode Mapper

from  Base
enablePadding()

Pad "packets".

from  Base
disablePadding()

Do not pad packets.

from  Base
enableContinuousBuffer()

Treat consecutive "packets" as if they are a continuous buffer.

from  Base
disableContinuousBuffer()

Treat consecutive packets as if they are a discontinuous buffer.

from  Base
bool
isValidEngine(int $engine)

Test for engine validity

setPreferredEngine(int $engine)

Sets the preferred crypt engine

from  Base
getEngine()

Returns the engine currently being utilized

from  Base
_setEngine()

Sets the engine as appropriate

from  Base
string
_encryptBlock(string $in)

Encrypts a block

string
_decryptBlock(string $in)

Decrypts a block

_setupKey()

Creates the key schedule

_setup()

Setup the self::ENGINE_INTERNAL $engine

from  Base
_setupMcrypt()

Setup the \phpseclib\Crypt\Base::ENGINE_MCRYPT $engine

string
_pad(string $text)

Pads a string

from  Base
string
_unpad(string $text)

Unpads a string.

from  Base
_clearBuffers()

Clears internal buffers

from  Base
string
_string_shift(string $string, int $index = 1)

String Shift

from  Base
string
_string_pop(string $string, int $index = 1)

String Pop

from  Base
_increment_str(string $var)

Increment the current string

from  Base
_setupInlineCrypt()

Setup the performance-optimized function for de/encrypt()

string
_createInlineCryptFunction(array $cipher_code)

Creates the performance-optimized function for en/decrypt()

from  Base
array
_getLambdaFunctions()

Holds the lambda_functions table (classwide)

from  Base
string
_hashInlineCryptFunction(string $bytes)

Generates a digest from $bytes

from  Base
int
safe_intval(string $x)

Convert float to int

from  Base
string
safe_intval_inline()

eval()'able string for in-line float to int

from  Base
do_nothing()

Dummy error handler to suppress mcrypt errors

from  Base

Details

__construct(int $mode = self::MODE_CBC)

Default Constructor.

Determines whether or not the mcrypt extension should be used.

$mode could be:

  • self::MODE_ECB

  • self::MODE_CBC

  • self::MODE_CTR

  • self::MODE_CFB

  • self::MODE_OFB

If not explicitly set, self::MODE_CBC will be used.

Parameters

int $mode

setIV(string $iv)

Sets the initialization vector. (optional)

SetIV is not required when self::MODE_ECB (or ie for AES: \phpseclib\Crypt\AES::MODE_ECB) is being used. If not explicitly set, it'll be assumed to be all zero's.

Parameters

string $iv

setKeyLength(int $length)

Sets the key length.

Valid key lengths are 8 to 1024. Calling this function after setting the key has no effect until the next \phpseclib\Crypt\RC2::setKey() call.

Parameters

int $length

int getKeyLength()

Returns the current key length

Return Value

int

int getBlockLength()

Returns the current block length in bits

Return Value

int

setKey(string $key, int $t1 = 0)

Sets the key.

Keys can be of any length. RC2, itself, uses 8 to 1024 bit keys (eg. strlen($key) <= 128), however, we only use the first 128 bytes if $key has more then 128 bytes in it, and set $key to a single null byte if it is empty.

If the key is not explicitly set, it'll be assumed to be a single null byte.

Parameters

string $key
int $t1 optional Effective key length in bits.

See also

Base::setKey

bool setPassword(string $password, string $method = 'pbkdf2')

Sets the password.

Depending on what $method is set to, setPassword()'s (optional) parameters are as follows: {@link http://en.wikipedia.org/wiki/PBKDF2 pbkdf2} or pbkdf1: $hash, $salt, $count, $dkLen

Where $hash (default = sha1) currently supports the following hashes: see: Crypt/Hash.php

Parameters

string $password
string $method

Return Value

bool

See also

r y

string encrypt(string $plaintext)

Encrypts a message.

Mostly a wrapper for \phpseclib\Crypt\Base::encrypt, with some additional OpenSSL handling code

Parameters

string $plaintext

Return Value

string $ciphertext

See also

\self::decrypt()

string decrypt(string $ciphertext)

Decrypts a message.

Mostly a wrapper for \phpseclib\Crypt\Base::decrypt, with some additional OpenSSL handling code

Parameters

string $ciphertext

Return Value

string $plaintext

See also

\self::encrypt()

string _openssl_ctr_process(string $plaintext, string $encryptIV, array $buffer)

OpenSSL CTR Processor

PHP's OpenSSL bindings do not operate in continuous mode so we'll wrap around it. Since the keystream for CTR is the same for both encrypting and decrypting this function is re-used by both Base::encrypt() and Base::decrypt(). Also, OpenSSL doesn't implement CTR for all of it's symmetric ciphers so this function will emulate CTR with ECB when necessary.

Parameters

string $plaintext
string $encryptIV
array $buffer

Return Value

string

See also

\self::encrypt()
\self::decrypt()

string _openssl_ofb_process(string $plaintext, string $encryptIV, array $buffer)

OpenSSL OFB Processor

PHP's OpenSSL bindings do not operate in continuous mode so we'll wrap around it. Since the keystream for OFB is the same for both encrypting and decrypting this function is re-used by both Base::encrypt() and Base::decrypt().

Parameters

string $plaintext
string $encryptIV
array $buffer

Return Value

string

See also

\self::encrypt()
\self::decrypt()

int _openssl_translate_mode()

phpseclib <-> OpenSSL Mode Mapper

May need to be overwritten by classes extending this one in some cases

Return Value

int

enablePadding()

Pad "packets".

Block ciphers working by encrypting between their specified [$this->]block_size at a time 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)

See also

\self::disablePadding()

disablePadding()

Do not pad packets.

See also

\self::enablePadding()

enableContinuousBuffer()

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 $rijndael->decrypt($rijndael->encrypt(substr($plaintext, 16, 16))); echo $rijndael->decrypt($rijndael->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 \phpseclib\Crypt*() 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 also

\self::disableContinuousBuffer()

disableContinuousBuffer()

Treat consecutive packets as if they are a discontinuous buffer.

The default behavior.

See also

\self::enableContinuousBuffer()

bool isValidEngine(int $engine)

Test for engine validity

This is mainly just a wrapper to set things up for \phpseclib\Crypt\Base::isValidEngine()

Parameters

int $engine

Return Value

bool

See also

Base::__construct

setPreferredEngine(int $engine)

Sets the preferred crypt engine

Currently, $engine could be:

  • \phpseclib\Crypt\Base::ENGINE_OPENSSL [very fast]

  • \phpseclib\Crypt\Base::ENGINE_MCRYPT [fast]

  • \phpseclib\Crypt\Base::ENGINE_INTERNAL [slow]

If the preferred crypt engine is not available the fastest available one will be used

Parameters

int $engine

See also

\self::__construct()

getEngine()

Returns the engine currently being utilized

See also

\self::_setEngine()

_setEngine()

Sets the engine as appropriate

See also

\self::__construct()

string _encryptBlock(string $in)

Encrypts a block

Parameters

string $in

Return Value

string

See also

Base::_encryptBlock
Base::encrypt

string _decryptBlock(string $in)

Decrypts a block

Parameters

string $in

Return Value

string

See also

Base::_decryptBlock
Base::decrypt

_setupKey()

Creates the key schedule

_setup()

Setup the self::ENGINE_INTERNAL $engine

(re)init, if necessary, the internal cipher $engine and flush all $buffers Used (only) if $engine == self::ENGINE_INTERNAL

_setup() will be called each time if $changed === true typically this happens when using one or more of following public methods:

  • setKey()

  • setIV()

  • disableContinuousBuffer()

  • First run of encrypt() / decrypt() with no init-settings

See also

\self::setKey()
\self::setIV()
\self::disableContinuousBuffer()

_setupMcrypt()

Setup the \phpseclib\Crypt\Base::ENGINE_MCRYPT $engine

string _pad(string $text)

Pads a string

Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize. $this->block_size - (strlen($text) % $this->block_size) bytes are added, each of which is equal to chr($this->block_size - (strlen($text) % $this->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.

Parameters

string $text

Return Value

string

See also

\self::_unpad()

string _unpad(string $text)

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.

Parameters

string $text

Return Value

string

See also

\self::_pad()

_clearBuffers()

Clears internal buffers

Clearing/resetting the internal buffers is done everytime after disableContinuousBuffer() or on cipher $engine (re)init ie after setKey() or setIV()

string _string_shift(string $string, int $index = 1)

String Shift

Inspired by array_shift

Parameters

string $string
int $index

Return Value

string

string _string_pop(string $string, int $index = 1)

String Pop

Inspired by array_pop

Parameters

string $string
int $index

Return Value

string

_increment_str(string $var)

Increment the current string

Parameters

string $var

See also

\self::decrypt()
\self::encrypt()

_setupInlineCrypt()

Setup the performance-optimized function for de/encrypt()

string _createInlineCryptFunction(array $cipher_code)

Creates the performance-optimized function for en/decrypt()

Internally for phpseclib developers:

_createInlineCryptFunction():

  • merge the $cipher_code [setup'ed by _setupInlineCrypt()] with the current [$this->]mode of operation code

  • create the $inline function, which called by encrypt() / decrypt() as its replacement to speed up the en/decryption operations.

  • return the name of the created $inline callback function

  • used to speed up en/decryption

The main reason why can speed up things [up to 50%] this way are:

  • using variables more effective then regular. (ie no use of expensive arrays but integers $k_0, $k_1 ... or even, for example, the pure $key[] values hardcoded)

  • avoiding 1000's of function calls of ie _encryptBlock() but inlining the crypt operations. in the mode of operation for() loop.

  • full loop unroll the (sometimes key-dependent) rounds avoiding this way ++$i counters and runtime-if's etc...

The basic code architectur of the generated $inline en/decrypt() lambda function, in pseudo php, is:

+----------------------------------------------------------------------------------------------+ | callback $inline = create_function: | | lambda_function_0001_crypt_ECB($action, $text) | | { | | INSERT PHP CODE OF: | | $cipher_code['init_crypt']; // general init code. | | // ie: $sbox'es declarations used for | | // encrypt and decrypt'ing. | | | | switch ($action) { | | case 'encrypt': | | INSERT PHP CODE OF: | | $cipher_code['init_encrypt']; // encrypt sepcific init code. | | ie: specified $key or $box | | declarations for encrypt'ing. | | | | foreach ($ciphertext) { | | $in = $block_size of $ciphertext; | | | | INSERT PHP CODE OF: | | $cipher_code['encrypt_block']; // encrypt's (string) $in, which is always: | | // strlen($in) == $this->block_size | | // here comes the cipher algorithm in action | | // for encryption. | | // $cipher_code['encrypt_block'] has to | | // encrypt the content of the $in variable | | | | $plaintext .= $in; | | } | | return $plaintext; | | | | case 'decrypt': | | INSERT PHP CODE OF: | | $cipher_code['init_decrypt']; // decrypt sepcific init code | | ie: specified $key or $box | | declarations for decrypt'ing. | | foreach ($plaintext) { | | $in = $block_size of $plaintext; | | | | INSERT PHP CODE OF: | | $cipher_code['decrypt_block']; // decrypt's (string) $in, which is always | | // strlen($in) == $this->block_size | | // here comes the cipher algorithm in action | | // for decryption. | | // $cipher_code['decrypt_block'] has to | | // decrypt the content of the $in variable | | $ciphertext .= $in; | | } | | return $ciphertext; | | } | | } | +----------------------------------------------------------------------------------------------+

See also the \phpseclib\Crypt*::_setupInlineCrypt()'s for productive inline $cipher_code's how they works.

Structure of: $cipher_code = array( 'init_crypt' => (string) '', // optional 'init_encrypt' => (string) '', // optional 'init_decrypt' => (string) '', // optional 'encrypt_block' => (string) '', // required 'decrypt_block' => (string) '' // required );

Parameters

array $cipher_code

Return Value

string (the name of the created callback function)

See also

\self::_setupInlineCrypt()
\self::encrypt()
\self::decrypt()

array _getLambdaFunctions()

Holds the lambda_functions table (classwide)

Each name of the lambda function, created from _setupInlineCrypt() && _createInlineCryptFunction() is stored, classwide (!), here for reusing.

The string-based index of $function is a classwide unique value representing, at least, the $mode of operation (or more... depends of the optimizing level) for which $mode the lambda function was created.

Return Value

array &$functions

string _hashInlineCryptFunction(string $bytes)

Generates a digest from $bytes

Parameters

string $bytes

Return Value

string

See also

\self::_setupInlineCrypt()

int safe_intval(string $x)

Convert float to int

On ARM CPUs converting floats to ints doesn't always work

Parameters

string $x

Return Value

int

string safe_intval_inline()

eval()'able string for in-line float to int

Return Value

string

do_nothing()

Dummy error handler to suppress mcrypt errors