ElGamal Class

Properties   Methods   Events   Config Settings   Errors  

Encrypt and decrypt data with the ElGamal asymmetric key encryption algorithm for public-key cryptography.

Class Name

IPWorksEncrypt_ElGamal

Procedural Interface

 ipworksencrypt_elgamal_open();
 ipworksencrypt_elgamal_close($res);
 ipworksencrypt_elgamal_register_callback($res, $id, $function);
 ipworksencrypt_elgamal_get_last_error($res);
 ipworksencrypt_elgamal_get_last_error_code($res);
 ipworksencrypt_elgamal_set($res, $id, $index, $value);
 ipworksencrypt_elgamal_get($res, $id, $index);
 ipworksencrypt_elgamal_do_config($res, $configurationstring);
 ipworksencrypt_elgamal_do_createkey($res);
 ipworksencrypt_elgamal_do_decrypt($res);
 ipworksencrypt_elgamal_do_encrypt($res);
 ipworksencrypt_elgamal_do_reset($res);

Remarks

The ElGamal class is used to encrypt/decrypt data with the ElGamal asymmetric key encryption algorithm for public-key cryptography.

To begin, you must either specify an existing key or create a new key. Existing public or private keys may be specified by setting Key. To create a new key pair, call CreateKey.

After specifying a key, specify the data you wish to encrypt or decrypt. Call the Encrypt or Decrypt method to perform the operation.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

An ElGamal key is made up of a number of individual parameters.

The public key consists of the following parameters:

• KeyP
• KeyG
• KeyY

The class also includes the KeyPublicKey property which holds the PEM formatted public key for ease of use. This is helpful if you are in control of both signature creation and verification process. When sending the public key to a recipient, note that not all implementations will support using the PEM formatted value in KeyPublicKey, in which case the individual parameters must be sent.

The private key consists of the following parameters:

• KeyP
• KeyG
• KeyY
• KeyX

The class also includes the KeyPrivateKey property which holds the PEM formatted private key for ease of use. This is helpful for storing the private key more easily.

Property List

---

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

Method List

---

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

Event List

---

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

---

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

InputFile Property (IPWorksEncrypt_ElGamal Class)

The file to process.

Object Oriented Interface

public function getInputFile();
public function setInputFile($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 1 );
ipworksencrypt_elgamal_set($res, 1, $value );

Default Value

''

Remarks

This property specifies the file to be processed. Set this property to the full or relative path to the file which will be processed.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

Data Type

String

InputMessage Property (IPWorksEncrypt_ElGamal Class)

The message to process.

Object Oriented Interface

public function getInputMessage();
public function setInputMessage($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 2 );
ipworksencrypt_elgamal_set($res, 2, $value );

Default Value

''

Remarks

This property specifies the message to be processed.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

Data Type

Binary String

KeyG Property (IPWorksEncrypt_ElGamal Class)

Represents the G parameter for the ElGamal algorithm.

Object Oriented Interface

public function getKeyG();
public function setKeyG($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 3 );
ipworksencrypt_elgamal_set($res, 3, $value );

Default Value

''

Remarks

Represents the G parameter for the ElGamal algorithm.

Data Type

Binary String

KeyP Property (IPWorksEncrypt_ElGamal Class)

Represents the P parameter for the ElGamal algorithm.

Object Oriented Interface

public function getKeyP();
public function setKeyP($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 4 );
ipworksencrypt_elgamal_set($res, 4, $value );

Default Value

''

Remarks

Represents the P parameter for the ElGamal algorithm.

Data Type

Binary String

KeyPrivateKey Property (IPWorksEncrypt_ElGamal Class)

This property is a PEM formatted private key.

Object Oriented Interface

public function getKeyPrivateKey();
public function setKeyPrivateKey($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 5 );
ipworksencrypt_elgamal_set($res, 5, $value );

Default Value

''

Remarks

This property is a PEM formatted private key. The purpose of this property is to allow easier management of the private key parameters by using only a single value.

Data Type

String

KeyPublicKey Property (IPWorksEncrypt_ElGamal Class)

This property is a PEM formatted public key.

Object Oriented Interface

public function getKeyPublicKey();
public function setKeyPublicKey($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 6 );
ipworksencrypt_elgamal_set($res, 6, $value );

Default Value

''

Remarks

This property is a PEM formatted public key. The purpose of this property is to allow easier management of the public key parameters by using only a single value.

Data Type

String

KeyX Property (IPWorksEncrypt_ElGamal Class)

Represents the X parameter for the ElGamal algorithm.

Object Oriented Interface

public function getKeyX();
public function setKeyX($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 7 );
ipworksencrypt_elgamal_set($res, 7, $value );

Default Value

''

Remarks

Represents the X parameter for the ElGamal algorithm.

Data Type

Binary String

KeyY Property (IPWorksEncrypt_ElGamal Class)

Represents the Y parameter for the ElGamal algorithm.

Object Oriented Interface

public function getKeyY();
public function setKeyY($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 8 );
ipworksencrypt_elgamal_set($res, 8, $value );

Default Value

''

Remarks

Represents the Y parameter for the ElGamal algorithm.

Data Type

Binary String

OutputFile Property (IPWorksEncrypt_ElGamal Class)

The output file when encrypting or decrypting.

Object Oriented Interface

public function getOutputFile();
public function setOutputFile($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 9 );
ipworksencrypt_elgamal_set($res, 9, $value );

Default Value

''

Remarks

This property specifies the file to which the output will be written when Encrypt or Decrypt is called. This may be set to an absolute or relative path.

This property is only applicable to Encrypt and Decrypt.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

Data Type

String

OutputMessage Property (IPWorksEncrypt_ElGamal Class)

The output message after processing.

Object Oriented Interface

public function getOutputMessage();

Procedural Interface

ipworksencrypt_elgamal_get($res, 10 );

Default Value

''

Remarks

This property will be populated with the output from the operation if OutputFile is not set.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

This property is read-only and not available at design time.

Data Type

Binary String

Overwrite Property (IPWorksEncrypt_ElGamal Class)

Indicates whether or not the class should overwrite files.

Object Oriented Interface

public function getOverwrite();
public function setOverwrite($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 11 );
ipworksencrypt_elgamal_set($res, 11, $value );

Default Value

false

Remarks

This property indicates whether or not the class will overwrite OutputFile. If Overwrite is False, an error will be thrown whenever OutputFile exists before an operation. The default value is False.

Data Type

Boolean

RecipientKeyG Property (IPWorksEncrypt_ElGamal Class)

Represents the G parameter for the ElGamal algorithm.

Object Oriented Interface

public function getRecipientKeyG();
public function setRecipientKeyG($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 12 );
ipworksencrypt_elgamal_set($res, 12, $value );

Default Value

''

Remarks

Represents the G parameter for the ElGamal algorithm.

Data Type

Binary String

RecipientKeyP Property (IPWorksEncrypt_ElGamal Class)

Represents the P parameter for the ElGamal algorithm.

Object Oriented Interface

public function getRecipientKeyP();
public function setRecipientKeyP($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 13 );
ipworksencrypt_elgamal_set($res, 13, $value );

Default Value

''

Remarks

Represents the P parameter for the ElGamal algorithm.

Data Type

Binary String

RecipientKeyPublicKey Property (IPWorksEncrypt_ElGamal Class)

This property is a PEM formatted public key.

Object Oriented Interface

public function getRecipientKeyPublicKey();
public function setRecipientKeyPublicKey($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 15 );
ipworksencrypt_elgamal_set($res, 15, $value );

Default Value

''

Remarks

This property is a PEM formatted public key. The purpose of this property is to allow easier management of the public key parameters by using only a single value.

Data Type

String

RecipientKeyY Property (IPWorksEncrypt_ElGamal Class)

Represents the Y parameter for the ElGamal algorithm.

Object Oriented Interface

public function getRecipientKeyY();
public function setRecipientKeyY($value);

Procedural Interface

ipworksencrypt_elgamal_get($res, 17 );
ipworksencrypt_elgamal_set($res, 17, $value );

Default Value

''

Remarks

Represents the Y parameter for the ElGamal algorithm.

Data Type

Binary String

UseHex Property (IPWorksEncrypt_ElGamal Class)

Whether input or output is hex encoded.

Object Oriented Interface

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

Procedural Interface

ipworksencrypt_elgamal_get($res, 18 );
ipworksencrypt_elgamal_set($res, 18, $value );

Default Value

false

Remarks

This property specifies whether the encrypted data is hex encoded.

If set to True, when Encrypt is called the class will perform the encryption as normal and then hex encode the output. OutputMessage or OutputFile will hold hex encoded data.

If set to True, when Decrypt is called the class will expect InputMessage or InputFile to hold hex encoded data. The class will then hex decode the data and perform decryption as normal.

Data Type

Boolean

Config Method (IPWorksEncrypt_ElGamal Class)

Sets or retrieves a configuration setting.

Object Oriented Interface

public function doConfig($configurationstring);

Procedural Interface

ipworksencrypt_elgamal_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_ElGamal Class)

Creates a new key.

Object Oriented Interface

public function doCreateKey();

Procedural Interface

ipworksencrypt_elgamal_do_createkey($res);

Remarks

This method creates a new public and private key.

When calling CreateKey the Key property is populated with a new private and public key.

An ElGamal key is made up of a number of individual parameters.

The public key consists of the following parameters:

• KeyP
• KeyG
• KeyY

The class also includes the KeyPublicKey property which holds the PEM formatted public key for ease of use. This is helpful if you are in control of both signature creation and verification process. When sending the public key to a recipient, note that not all implementations will support using the PEM formatted value in KeyPublicKey, in which case the individual parameters must be sent.

The private key consists of the following parameters:

• KeyP
• KeyG
• KeyY
• KeyX

The class also includes the KeyPrivateKey property which holds the PEM formatted private key for ease of use. This is helpful for storing the private key more easily.

Decrypt Method (IPWorksEncrypt_ElGamal Class)

Decrypts the input data using the specified private key.

Object Oriented Interface

public function doDecrypt();

Procedural Interface

ipworksencrypt_elgamal_do_decrypt($res);

Remarks

This method decrypts the input data using the private key specified in Key. Alternatively, a certificate may be specified by setting Certificate.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

Key Size and the Maximum Length of Data

RSA has an upper limit to the amount of data that can be encrypted or decrypted, also known as message length. This can typically be calculated as the size of the key minus the size of the RSA header and padding.

When not using OAEP, the following formula and table can be referenced. (RSA Key Bytes) - (Header Bytes) = Length of data, where Header Bytes is always 11.

When using OAEP, the following formula and table can be referenced. (RSA Key Bytes) - (2 * Hash Length Bytes) - 2 = Length of data. The table below assumes SHA-256 for the hash, so Hash Length Bytes is 32.

Encrypt Method (IPWorksEncrypt_ElGamal Class)

Encrypts the input data using the recipient's public key.

Object Oriented Interface

public function doEncrypt();

Procedural Interface

ipworksencrypt_elgamal_do_encrypt($res);

Remarks

This method encrypts the input data using the public key specified in RecipientKey. Alternatively, a certificate may be specified by setting RecipientCert.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

• InputFile
• InputMessage

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

• OutputFile
• OutputMessage: The output data is written to this property if no other destination is specified.

Key Size and the Maximum Length of Data

RSA has an upper limit to the amount of data that can be encrypted or decrypted, also known as message length. This can typically be calculated as the size of the key minus the size of the RSA header and padding.

When not using OAEP, the following formula and table can be referenced. (RSA Key Bytes) - (Header Bytes) = Length of data, where Header Bytes is always 11.

When using OAEP, the following formula and table can be referenced. (RSA Key Bytes) - (2 * Hash Length Bytes) - 2 = Length of data. The table below assumes SHA-256 for the hash, so Hash Length Bytes is 32.

Reset Method (IPWorksEncrypt_ElGamal Class)

Resets the class.

Object Oriented Interface

public function doReset();

Procedural Interface

ipworksencrypt_elgamal_do_reset($res);

Remarks

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

Error Event (IPWorksEncrypt_ElGamal Class)

Fired when information is available about errors during data delivery.

Object Oriented Interface

public function fireError($param);

Procedural Interface

ipworksencrypt_elgamal_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 (ElGamal 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.

ElGamal Config Settings

Base Config Settings

Trappable Errors (ElGamal Class)

ElGamal Errors