PBKDF Class

Properties   Methods   Events   Config Settings   Errors  

The PBKDF class supports using PBKDF1 and PBKDF2 to derive a key using a variety of algorithms.

Class Name

IPWorksEncrypt_PBKDF

Procedural Interface

 ipworksencrypt_pbkdf_open();
 ipworksencrypt_pbkdf_close($res);
 ipworksencrypt_pbkdf_register_callback($res, $id, $function);
 ipworksencrypt_pbkdf_get_last_error($res);
 ipworksencrypt_pbkdf_get_last_error_code($res);
 ipworksencrypt_pbkdf_set($res, $id, $index, $value);
 ipworksencrypt_pbkdf_get($res, $id, $index);
 ipworksencrypt_pbkdf_do_config($res, $configurationstring);
 ipworksencrypt_pbkdf_do_createkey($res);
 ipworksencrypt_pbkdf_do_reset($res);

Remarks

The PBKDF component implements PBKDF2 and PBKDF1 (Password-Based Key Derivation Function 1 & 2) as described in RFC 2898.

The simplest way to use the component is to simply specify the Password and Salt and call CreateKey. Before calling CreateKey additional properties such as Algorithm, KeyLength, and Iterations may be set. The component supports a variety of algorithms including HMAC-SHA1, HMAC-SHA256, HMAC-MD5, and more.

The Version property controls whether PBKDF1 or PBKDF2 (default) is used, although it is recommended to use PBKDF2.

After calling CreateKey the derived key will be held in Key.

Code Example: Pbkdf pbkdf = new Pbkdf(); pbkdf.Password = "password"; pbkdf.Salt = "0123456789ABCDEF"; pbkdf.KeyLength = 4096; pbkdf.CreateKey(); //Now do something with pbkdf.Key

Property List

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The following is the full list of the properties of the class with short descriptions. Click on the links for further details.

Method List

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The following is the full list of the methods of the class with short descriptions. Click on the links for further details.

Event List

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The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.

Config Settings

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The following is a list of config settings for the class with short descriptions. Click on the links for further details.

Algorithm Property (IPWorksEncrypt_PBKDF Class)

The underlying pseudorandom function.

Object Oriented Interface

public function getAlgorithm();
public function setAlgorithm($value);

Procedural Interface

ipworksencrypt_pbkdf_get($res, 1 );
ipworksencrypt_pbkdf_set($res, 1, $value );

Default Value

0

Remarks

This property specifies the algorithm used for the pseudo random function. Possible values are:

Note: When using PBDKF1 the maximum KeyLength value is 160 bits for SHA1, and 128 bits for MD2 and MD5.

Data Type

Integer

Iterations Property (IPWorksEncrypt_PBKDF Class)

The number of iterations to perform.

Object Oriented Interface

public function getIterations();
public function setIterations($value);

Procedural Interface

ipworksencrypt_pbkdf_get($res, 2 );
ipworksencrypt_pbkdf_set($res, 2, $value );

Default Value

10000

Remarks

This property specifies the number of iterations to perform when deriving the key. Larger values require more time to derive a key, however they also make password cracking more difficult by increasing the amount of time required to derive each key.

The recommended minimum number of iterations is 1000, and larger values such as 10,000 are common. The default value is 10000.

Data Type

Integer

Key Property (IPWorksEncrypt_PBKDF Class)

The derived key.

Object Oriented Interface

public function getKey();

Procedural Interface

ipworksencrypt_pbkdf_get($res, 3 );

Default Value

''

Remarks

This property holds the derived key. After calling CreateKey this property will be populated.

This property is read-only.

Data Type

Binary String

KeyLength Property (IPWorksEncrypt_PBKDF Class)

The desired length in bits of the derived key.

Object Oriented Interface

public function getKeyLength();
public function setKeyLength($value);

Procedural Interface

ipworksencrypt_pbkdf_get($res, 4 );
ipworksencrypt_pbkdf_set($res, 4, $value );

Default Value

1024

Remarks

This property specifies the length in bits of the Key.

The provided value must be divisible by 8. The default value is 1024.

Note: When Version is set to PBKDF1 certain restrictions apply. When Algorithm is set to MD5 the maximum length is 128. When Algorithm is set to SHA1 the maximum value is 160.

Data Type

Integer

Password Property (IPWorksEncrypt_PBKDF Class)

The password from which a derived key is generated.

Object Oriented Interface

public function getPassword();
public function setPassword($value);

Procedural Interface

ipworksencrypt_pbkdf_get($res, 5 );
ipworksencrypt_pbkdf_set($res, 5, $value );

Default Value

''

Remarks

This property specifies the password from which the derived key is created.

Data Type

Binary String

Salt Property (IPWorksEncrypt_PBKDF Class)

The cryptographic salt.

Object Oriented Interface

public function getSalt();
public function setSalt($value);

Procedural Interface

ipworksencrypt_pbkdf_get($res, 6 );
ipworksencrypt_pbkdf_set($res, 6, $value );

Default Value

''

Remarks

This property specifies the salt used during key creation.

It is recommended to provide a salt value of at least 64 bits in length. A common length is 128 bits. It is also recommended that the salt value be randomly chosen.

Data Type

Binary String

UseHex Property (IPWorksEncrypt_PBKDF Class)

Whether the key is hex encoded.

Object Oriented Interface

public function getUseHex();
public function setUseHex($value);

Procedural Interface

ipworksencrypt_pbkdf_get($res, 7 );
ipworksencrypt_pbkdf_set($res, 7, $value );

Default Value

false

Remarks

This setting specifies whether the created Key is hex encoded when calling CreateKey. The default value is False.

Data Type

Boolean

Version Property (IPWorksEncrypt_PBKDF Class)

The PBKDF version.

Object Oriented Interface

public function getVersion();
public function setVersion($value);

Procedural Interface

ipworksencrypt_pbkdf_get($res, 8 );
ipworksencrypt_pbkdf_set($res, 8, $value );

Default Value

1

Remarks

This property specifies the PBKDF version to be used. It is recommended to use PBKDF2 for new applications. PBKDF1 is included only for compatibility with existing applications and is not recommended.

Possible values are:

• 0 (vPBKDF1)
• 1 (vPBKDF2 - default)

Data Type

Integer

Config Method (IPWorksEncrypt_PBKDF Class)

Sets or retrieves a configuration setting.

Object Oriented Interface

public function doConfig($configurationstring);

Procedural Interface

ipworksencrypt_pbkdf_do_config($res, $configurationstring);

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

CreateKey Method (IPWorksEncrypt_PBKDF Class)

Creates a key.

Object Oriented Interface

public function doCreateKey();

Procedural Interface

ipworksencrypt_pbkdf_do_createkey($res);

Remarks

This method creates a key using a version of the Password-Based Key Derivation Function (PBKDF).

The following properties are applicable when calling this method:

• Password (required)
• Salt (required)
• Algorithm
• Iterations
• KeyLength
• Version

This method populates the Key property with the created (derived) key.

Code Example: Pbkdf pbkdf = new Pbkdf(); pbkdf.Password = "password"; pbkdf.Salt = "0123456789ABCDEF"; pbkdf.KeyLength = 4096; pbkdf.CreateKey(); //Now do something with pbkdf.Key

Reset Method (IPWorksEncrypt_PBKDF Class)

Resets the class.

Object Oriented Interface

public function doReset();

Procedural Interface

ipworksencrypt_pbkdf_do_reset($res);

Remarks

When called, the class will reset all of its properties to their default values.

Error Event (IPWorksEncrypt_PBKDF Class)

Fired when information is available about errors during data delivery.

Object Oriented Interface

public function fireError($param);

Procedural Interface

ipworksencrypt_pbkdf_register_callback($res, 1, array($this, 'fireError'));

Parameter List

 'errorcode'
 'description'

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class fails with an error.

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

Config Settings (PBKDF Class)

The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

PBKDF Config Settings

Base Config Settings

Trappable Errors (PBKDF Class)

PBKDF Errors