phpseclib API Documentation
Class

Crypt_AES

class Crypt_AES extends Crypt_Rijndael

Pure-PHP implementation of AES.

Properties

int $mode The Encryption Mode
int $block_size The Block Length of the block cipher
string $key The Key
string $iv The Initialization Vector
string $encryptIV A "sliding" Initialization Vector
string $decryptIV A "sliding" Initialization Vector
bool $continuousBuffer Continuous Buffer status
array $enbuffer Encryption buffer for CTR, OFB and CFB modes
array $debuffer Decryption buffer for CTR, OFB and CFB modes
resource $enmcrypt mcrypt resource for encryption
resource $demcrypt mcrypt resource for decryption
bool $enchanged Does the enmcrypt resource need to be (re)initialized?
bool $dechanged Does the demcrypt resource need to be (re)initialized?
resource $ecb mcrypt resource for CFB mode
int $cfb_init_len Optimizing value while CFB-encrypting
bool $changed Does internal cipher state need to be (re)initialized?
bool $padding Padding status
bool $paddable Is the mode one that is paddable?
int $engine Holds which crypt engine internaly should be use, which will be determined automatically on __construct()
int $preferredEngine Holds the preferred crypt engine
string $cipher_name_mcrypt The mcrypt specific name of the cipher
string $cipher_name_openssl The openssl specific name of the cipher
string $cipher_name_openssl_ecb The openssl specific name of the cipher in ECB mode
string $password_default_salt The default salt used by setPassword()
string $const_namespace The namespace used by the cipher for its constants.
Callback $inline_crypt The name of the performance-optimized callback function
mixed $use_inline_crypt Holds whether performance-optimized $inline_crypt() can/should be used.
bool $openssl_emulate_ctr If OpenSSL can be used in ECB but not in CTR we can emulate CTR
mixed $openssl_options Determines what options are passed to openssl_encrypt/decrypt
bool $explicit_key_length Has the key length explicitly been set or should it be derived from the key, itself?
bool $skip_key_adjustment Don't truncate / null pad key
array $w The Key Schedule
array $dw The Inverse Key Schedule
int $Nb The Block Length divided by 32
int $key_length The Key Length (in bytes)
int $Nk The Key Length divided by 32
int $Nr The Number of Rounds
array $c Shift offsets
array $kl Holds the last used key- and block_size information

Methods

Crypt_Base(int $mode = CRYPT_MODE_CBC)

Default Constructor.

from Crypt_Base
setIV(string $iv)

Sets the initialization vector.

from Crypt_Base
setKeyLength(int $length)

Sets the key length

int getKeyLength()

Returns the current key length in bits

from Crypt_Base
int getBlockLength()

Returns the current block length in bits

from Crypt_Base
setKey(string $key)

Sets the key.

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

Sets the password.

from Crypt_Base
string encrypt(string $plaintext)

Encrypts a message.

from Crypt_Base
string decrypt(string $ciphertext)

Decrypts a message.

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

OpenSSL CTR Processor

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

OpenSSL OFB Processor

from Crypt_Base
int _openssl_translate_mode()

phpseclib <-> OpenSSL Mode Mapper

from Crypt_Base
enablePadding()

Pad "packets".

from Crypt_Base
disablePadding()

Do not pad packets.

from Crypt_Base
enableContinuousBuffer()

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

from Crypt_Base
disableContinuousBuffer()

Treat consecutive packets as if they are a discontinuous buffer.

from Crypt_Base
bool isValidEngine(int $engine)

Test for engine validity

from Crypt_Rijndael
setPreferredEngine(int $engine)

Sets the preferred crypt engine

from Crypt_Base
getEngine()

Returns the engine currently being utilized

from Crypt_Base
_setEngine()

Sets the engine as appropriate

from Crypt_Base
string _encryptBlock(string $in)

Encrypts a block

from Crypt_Rijndael
string _decryptBlock(string $in)

Decrypts a block

from Crypt_Rijndael
_setupKey()

Setup the key (expansion)

from Crypt_Rijndael
_setup()

Setup the CRYPTENGINEINTERNAL $engine

from Crypt_Base
_setupMcrypt()

Setup the CRYPTENGINEMCRYPT $engine

from Crypt_Base
string _pad(string $text)

Pads a string

from Crypt_Base
string _unpad(string $text)

Unpads a string.

from Crypt_Base
_clearBuffers()

Clears internal buffers

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

String Shift

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

String Pop

from Crypt_Base
_increment_str(string $var)

Increment the current string

from Crypt_Base
_setupInlineCrypt()

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

from Crypt_Rijndael
string _createInlineCryptFunction(array $cipher_code)

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

from Crypt_Base
array _getLambdaFunctions()

Holds the lambda_functions table (classwide)

from Crypt_Base
string _hashInlineCryptFunction($bytes $bytes)

Generates a digest from $bytes

from Crypt_Base
Crypt_Rijndael(int $mode = CRYPT_RIJNDAEL_MODE_CBC)

Default Constructor.

from Crypt_Rijndael
setBlockLength(int $length)

Dummy function

_subWord(int $word)

Performs S-Box substitutions

from Crypt_Rijndael
array _getTables()

Provides the mixColumns and sboxes tables

from Crypt_Rijndael
array _getInvTables()

Provides the inverse mixColumns and inverse sboxes tables

from Crypt_Rijndael

Details

in Crypt_Base at line 506
public Crypt_Base(int $mode = CRYPT_MODE_CBC)

Default Constructor.

Determines whether or not the mcrypt extension should be used.

$mode could be:

(or the alias constants of the chosen cipher, for example for AES: CRYPTAESMODEECB or CRYPTAESMODECBC ...)

If not explicitly set, CRYPTMODECBC will be used.

Parameters

int $mode

in Crypt_Base at line 544
public setIV(string $iv)

Sets the initialization vector.

(optional)

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

Parameters

string $iv

at line 156
public setKeyLength(int $length)

Sets the key length

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

Parameters

int $length

See also

Crypt_Rijndael:setKeyLength()

in Crypt_Base at line 575
public int getKeyLength()

Returns the current key length in bits

Return Value

int

in Crypt_Base at line 586
public int getBlockLength()

Returns the current block length in bits

Return Value

int

at line 178
public setKey(string $key)

Sets the key.

Rijndael supports five different key lengths, AES only supports three.

Parameters

string $key

See also

Crypt_Rijndael:setKey()
setKeyLength()

in Crypt_Base at line 633
public 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

Crypt/Hash.php

in Crypt_Base at line 730
public string encrypt(string $plaintext)

Encrypts a message.

$plaintext will be padded with additional bytes such that it's length is a multiple of the block size. Other cipher 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 the block size, however, arbitrary values can be added to make it that length.

Parameters

string $plaintext

Return Value

string $ciphertext

See also

self::decrypt()

in Crypt_Base at line 1031
public string decrypt(string $ciphertext)

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.

Parameters

string $ciphertext

Return Value

string $plaintext

See also

self::encrypt()

in Crypt_Base at line 1327
public 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 CryptBase::encrypt() and CryptBase::decrypt(). Also, OpenSSL doesn't implement CTR for all of it's symmetric ciphers so this function will emulate CTR with ECB when necesary.

Parameters

string $plaintext
string $encryptIV
array $buffer

Return Value

string

See also

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

in Crypt_Base at line 1421
public 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 CryptBase::encrypt() and CryptBase::decrypt().

Parameters

string $plaintext
string $encryptIV
array $buffer

Return Value

string

See also

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

in Crypt_Base at line 1467
public int _openssl_translate_mode()

phpseclib <-> OpenSSL Mode Mapper

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

Return Value

int

in Crypt_Base at line 1498
public 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()

in Crypt_Base at line 1509
public disablePadding()

Do not pad packets.

See also

self::enablePadding()

in Crypt_Base at line 1552
public 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 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()

in Crypt_Base at line 1572
public disableContinuousBuffer()

Treat consecutive packets as if they are a discontinuous buffer.

The default behavior.

See also

self::enableContinuousBuffer()

in Crypt_Rijndael at line 388
public bool isValidEngine(int $engine)

Test for engine validity

This is mainly just a wrapper to set things up for Crypt_Base::isValidEngine()

Parameters

int $engine

Return Value

bool

See also

Crypt_Base::Crypt_Base()

in Crypt_Base at line 1661
public setPreferredEngine(int $engine)

Sets the preferred crypt engine

Currently, $engine could be:

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

Parameters

int $engine

See also

self::Crypt_Base()

in Crypt_Base at line 1682
public getEngine()

Returns the engine currently being utilized

See also

self::_setEngine()

in Crypt_Base at line 1693
public _setEngine()

Sets the engine as appropriate

See also

self::Crypt_Base()

in Crypt_Rijndael at line 416
public string _encryptBlock(string $in)

Encrypts a block

Parameters

string $in

Return Value

string

in Crypt_Rijndael at line 517
public string _decryptBlock(string $in)

Decrypts a block

Parameters

string $in

Return Value

string

in Crypt_Rijndael at line 606
public _setupKey()

Setup the key (expansion)

See also

Crypt_Base::_setupKey()

in Crypt_Base at line 1793
public _setup()

Setup the CRYPTENGINEINTERNAL $engine

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

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

See also

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

in Crypt_Base at line 1826
public _setupMcrypt()

Setup the CRYPTENGINEMCRYPT $engine

(re)init, if necessary, the (ext)mcrypt resources and flush all $buffers Used (only) if $engine = CRYPTENGINEMCRYPT

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

See also

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

in Crypt_Base at line 1872
public 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. $this->blocksize - (strlen($text) % $this->blocksize) bytes are added, each of which is equal to chr($this->blocksize - (strlen($text) % $this->blocksize)

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()

in Crypt_Base at line 1901
public 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()

in Crypt_Base at line 1926
public _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()

in Crypt_Base at line 1949
public string _string_shift(string $string, int $index = 1)

String Shift

Inspired by array_shift

Parameters

string $string
int $index

Return Value

string

in Crypt_Base at line 1966
public string _string_pop(string $string, int $index = 1)

String Pop

Inspired by array_pop

Parameters

string $string
int $index

Return Value

string

in Crypt_Base at line 1981
public _increment_str(string $var)

Increment the current string

Parameters

string $var

See also

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

in Crypt_Rijndael at line 911
public _setupInlineCrypt()

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

See also

Crypt_Base::_setupInlineCrypt()

in Crypt_Base at line 2192
public string _createInlineCryptFunction(array $cipher_code)

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

Internally for phpseclib developers:

_createInlineCryptFunction():

Parameters

array $cipher_code

Return Value

string (the name of the created callback function)

See also

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

in Crypt_Base at line 2559
public 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 uniqe 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

in Crypt_Base at line 2573
public string _hashInlineCryptFunction($bytes $bytes)

Generates a digest from $bytes

Parameters

$bytes $bytes

Return Value

string

See also

self::_setupInlineCrypt()

in Crypt_Rijndael at line 267
public Crypt_Rijndael(int $mode = CRYPT_RIJNDAEL_MODE_CBC)

Default Constructor.

Determines whether or not the mcrypt extension should be used.

$mode could be:

If not explictly set, CRYPTRIJNDAELMODE_CBC will be used.

Parameters

int $mode

See also

Crypt_Base::Crypt_Base()

at line 141
public setBlockLength(int $length)

Dummy function

Since CryptAES extends CryptRijndael, this function is, technically, available, but it doesn't do anything.

Parameters

int $length

See also

Crypt_Rijndael::setBlockLength()

in Crypt_Rijndael at line 719
public _subWord(int $word)

Performs S-Box substitutions

Parameters

int $word

in Crypt_Rijndael at line 741
public array _getTables()

Provides the mixColumns and sboxes tables

Return Value

array &$tables

See also

Crypt_Rijndael:_encryptBlock()
Crypt_Rijndael:_setupInlineCrypt()
Crypt_Rijndael:_subWord()

in Crypt_Rijndael at line 830
public array _getInvTables()

Provides the inverse mixColumns and inverse sboxes tables

Return Value

array &$tables

See also

Crypt_Rijndael:_decryptBlock()
Crypt_Rijndael:_setupInlineCrypt()
Crypt_Rijndael:_setupKey()