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.

Syntax

ipworksencrypt.Pbkdf

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 (PBKDF Class)

The underlying pseudorandom function.

Syntax

public int getAlgorithm();


public void setAlgorithm(int algorithm);


Enumerated values:
  public final static int pbHMACSHA1 = 0;
  public final static int pbHMACSHA224 = 1;
  public final static int pbHMACSHA256 = 2;
  public final static int pbHMACSHA384 = 3;
  public final static int pbHMACSHA512 = 4;
  public final static int pbHMACMD5 = 5;
  public final static int pbHMACRIPEMD160 = 6;
  public final static int pbSHA1 = 7;
  public final static int pbMD5 = 8;
  public final static int pbMD2 = 9;

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.

Iterations Property (PBKDF Class)

The number of iterations to perform.

Syntax

public int getIterations();


public void setIterations(int iterations);

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.

Key Property (PBKDF Class)

The derived key.

Syntax

public byte[] getKey();

Default Value

""

Remarks

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

This property is read-only.

KeyLength Property (PBKDF Class)

The desired length in bits of the derived key.

Syntax

public int getKeyLength();


public void setKeyLength(int keyLength);

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.

Password Property (PBKDF Class)

The master password from which a derived key is generated.

Syntax

public byte[] getPassword();


public void setPassword(byte[] password);

Default Value

""

Remarks

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

Salt Property (PBKDF Class)

The cryptographic salt.

Syntax

public byte[] getSalt();


public void setSalt(byte[] salt);

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.

UseHex Property (PBKDF Class)

Whether the key is hex encoded.

Syntax

public boolean isUseHex();


public void setUseHex(boolean useHex);

Default Value

False

Remarks

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

Version Property (PBKDF Class)

The PBKDF version.

Syntax

public int getVersion();


public void setVersion(int version);


Enumerated values:
  public final static int vPBKDF1 = 0;
  public final static int vPBKDF2 = 1;

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)

Config Method (Pbkdf Class)

Sets or retrieves a configuration setting.

Syntax

public String config(String 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 (Pbkdf Class)

Creates a key.

Syntax

public void createKey();

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 (Pbkdf Class)

Resets the class.

Syntax

public void reset();

Remarks

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

Error Event (Pbkdf Class)

Information about errors during data delivery.

Syntax

public class DefaultPbkdfEventListener implements PbkdfEventListener {
  ...
  public void error(PbkdfErrorEvent e) {}
  ...
}

public class PbkdfErrorEvent {
  public int errorCode;
  public String description;
}

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class throws an exception.

ErrorCode contains an error code and Description 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

	116   Password must be set.
	117   An error occurred during hash calculation.
	118   An invalid algorithm was specified.