Elgamal Class
Properties Methods Events Config Settings Errors
Encrypt and decrypt data with the Elgamal asymmetric key encryption algorithm for public-key cryptography.
Syntax
class ipworksencrypt.Elgamal
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 the Key* properties. To create a new key pair call create_key.
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:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: 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:
The class also includes the key_public_key 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 key_public_key in which case the individual parameters must be sent.
The private key consists of the following parameters:
The class also include the key_private_key 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.
| input_file | The file to process. |
| input_message | The message to process. |
| keyg | Represents the G parameter for the Elgamal algorithm. |
| keyp | Represents the P parameter for the Elgamal algorithm. |
| key_private_key | This property is a PEM formatted private key. |
| key_public_key | This property is a PEM formatted public key. |
| keyx | Represents the X parameter for the Elgamal algorithm. |
| keyy | Represents the Y parameter for the Elgamal algorithm. |
| output_file | The output file when encrypting or decrypting. |
| output_message | The output message after processing. |
| overwrite | Indicates whether or not the class should overwrite files. |
| recipient_keyg | Represents the G parameter for the Elgamal algorithm. |
| recipient_keyp | Represents the P parameter for the Elgamal algorithm. |
| recipient_key_public_key | This property is a PEM formatted public key. |
| recipient_keyy | Represents the Y parameter for the Elgamal algorithm. |
| use_hex | Whether input or output is hex encoded. |
Method List
The following is the full list of the methods of the class with short descriptions. Click on the links for further details.
| config | Sets or retrieves a configuration setting. |
| create_key | Creates a new key. |
| decrypt | Decrypts the input data using the specified private key. |
| encrypt | Encrypts the input data using the recipient's public key. |
| reset | Resets the class. |
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.
| on_error | Information about errors during data delivery. |
Config Settings
The following is a list of config settings for the class with short descriptions. Click on the links for further details.
| KeySize | The size, in bits, of the secret key. |
| BuildInfo | Information about the product's build. |
| CodePage | The system code page used for Unicode to Multibyte translations. |
| LicenseInfo | Information about the current license. |
| ProcessIdleEvents | Whether the class uses its internal event loop to process events when the main thread is idle. |
| SelectWaitMillis | The length of time in milliseconds the class will wait when DoEvents is called if there are no events to process. |
| UseInternalSecurityAPI | Tells the class whether or not to use the system security libraries or an internal implementation. |
input_file Property
The file to process.
Syntax
def get_input_file() -> str: ... def set_input_file(value: str) -> None: ...
input_file = property(get_input_file, set_input_file)
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:
- input_file
- input_message
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: The output data is written to this property if no other destination is specified.
input_message Property
The message to process.
Syntax
def get_input_message() -> bytes: ... def set_input_message(value: bytes) -> None: ...
input_message = property(get_input_message, set_input_message)
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:
- input_file
- input_message
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: The output data is written to this property if no other destination is specified.
keyg Property
Represents the G parameter for the Elgamal algorithm.
Syntax
def get_keyg() -> bytes: ... def set_keyg(value: bytes) -> None: ...
keyg = property(get_keyg, set_keyg)
Default Value
""
Remarks
Represents the G parameter for the Elgamal algorithm.
keyp Property
Represents the P parameter for the Elgamal algorithm.
Syntax
def get_keyp() -> bytes: ... def set_keyp(value: bytes) -> None: ...
keyp = property(get_keyp, set_keyp)
Default Value
""
Remarks
Represents the P parameter for the Elgamal algorithm.
key_private_key Property
This property is a PEM formatted private key.
Syntax
def get_key_private_key() -> str: ... def set_key_private_key(value: str) -> None: ...
key_private_key = property(get_key_private_key, set_key_private_key)
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.
key_public_key Property
This property is a PEM formatted public key.
Syntax
def get_key_public_key() -> str: ... def set_key_public_key(value: str) -> None: ...
key_public_key = property(get_key_public_key, set_key_public_key)
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.
keyx Property
Represents the X parameter for the Elgamal algorithm.
Syntax
def get_keyx() -> bytes: ... def set_keyx(value: bytes) -> None: ...
keyx = property(get_keyx, set_keyx)
Default Value
""
Remarks
Represents the X parameter for the Elgamal algorithm.
keyy Property
Represents the Y parameter for the Elgamal algorithm.
Syntax
def get_keyy() -> bytes: ... def set_keyy(value: bytes) -> None: ...
keyy = property(get_keyy, set_keyy)
Default Value
""
Remarks
Represents the Y parameter for the Elgamal algorithm.
output_file Property
The output file when encrypting or decrypting.
Syntax
def get_output_file() -> str: ... def set_output_file(value: str) -> None: ...
output_file = property(get_output_file, set_output_file)
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:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: The output data is written to this property if no other destination is specified.
output_message Property
The output message after processing.
Syntax
def get_output_message() -> bytes: ...
output_message = property(get_output_message, None)
Default Value
""
Remarks
This property will be populated with the output from the operation if output_file 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:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: The output data is written to this property if no other destination is specified.
This property is read-only.
overwrite Property
Indicates whether or not the class should overwrite files.
Syntax
def get_overwrite() -> bool: ... def set_overwrite(value: bool) -> None: ...
overwrite = property(get_overwrite, set_overwrite)
Default Value
FALSE
Remarks
This property indicates whether or not the class will overwrite output_file. If overwrite is False, an error will be thrown whenever output_file exists before an operation. The default value is False.
recipient_keyg Property
Represents the G parameter for the Elgamal algorithm.
Syntax
def get_recipient_keyg() -> bytes: ... def set_recipient_keyg(value: bytes) -> None: ...
recipient_keyg = property(get_recipient_keyg, set_recipient_keyg)
Default Value
""
Remarks
Represents the G parameter for the Elgamal algorithm.
recipient_keyp Property
Represents the P parameter for the Elgamal algorithm.
Syntax
def get_recipient_keyp() -> bytes: ... def set_recipient_keyp(value: bytes) -> None: ...
recipient_keyp = property(get_recipient_keyp, set_recipient_keyp)
Default Value
""
Remarks
Represents the P parameter for the Elgamal algorithm.
recipient_key_public_key Property
This property is a PEM formatted public key.
Syntax
def get_recipient_key_public_key() -> str: ... def set_recipient_key_public_key(value: str) -> None: ...
recipient_key_public_key = property(get_recipient_key_public_key, set_recipient_key_public_key)
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.
recipient_keyy Property
Represents the Y parameter for the Elgamal algorithm.
Syntax
def get_recipient_keyy() -> bytes: ... def set_recipient_keyy(value: bytes) -> None: ...
recipient_keyy = property(get_recipient_keyy, set_recipient_keyy)
Default Value
""
Remarks
Represents the Y parameter for the Elgamal algorithm.
use_hex Property
Whether input or output is hex encoded.
Syntax
def get_use_hex() -> bool: ... def set_use_hex(value: bool) -> None: ...
use_hex = property(get_use_hex, set_use_hex)
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. output_message or output_file will hold hex encoded data.
If set to True, when decrypt is called the class will expect input_message or input_file to hold hex encoded data. The class will then hex decode the data and perform decryption as normal.
config Method
Sets or retrieves a configuration setting.
Syntax
def config(configuration_string: str) -> str: ...
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.
create_key Method
Creates a new key.
Syntax
def create_key() -> None: ...
Remarks
This method creates a new public and private key.
When calling create_key the Key* properties are 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:
The class also includes the key_public_key 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 key_public_key in which case the individual parameters must be sent.
The private key consists of the following parameters:
The class also include the key_private_key property which holds the PEM formatted private key for ease of use. This is helpful for storing the private key more easily.decrypt Method
Decrypts the input data using the specified private key.
Syntax
def decrypt() -> None: ...
Remarks
This method decrypts the input data using the private key specified in the Key* properties. 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:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: 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.
| RSA Key Length (bits) | Length (bits) | Length (bytes) |
| 1024 | 936 | 117 |
| 2048 | 1960 | 245 |
| 3072 | 2984 | 373 |
| 4096 | 4008 | 501 |
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.
| RSA Key Length (bits) | Length (bits) | Length (bytes) |
| 1024 | 496 | 62 |
| 2048 | 1520 | 190 |
| 3072 | 2544 | 318 |
| 4096 | 3568 | 446 |
encrypt Method
Encrypts the input data using the recipient's public key.
Syntax
def encrypt() -> None: ...
Remarks
This method encrypts the input data using the public key specified in the RecipientKey* properties. Alternatively, a certificate may be specified by setting recipient_cert
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:
When a valid source is found the search stops. The order in which the output properties are checked is as follows:
- output_file
- output_message: 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.
| RSA Key Length (bits) | Length (bits) | Length (bytes) |
| 1024 | 936 | 117 |
| 2048 | 1960 | 245 |
| 3072 | 2984 | 373 |
| 4096 | 4008 | 501 |
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.
| RSA Key Length (bits) | Length (bits) | Length (bytes) |
| 1024 | 496 | 62 |
| 2048 | 1520 | 190 |
| 3072 | 2544 | 318 |
| 4096 | 3568 | 446 |
reset Method
Resets the class.
Syntax
def reset() -> None: ...
Remarks
When called, the class will reset all of its properties to their default values.
on_error Event
Information about errors during data delivery.
Syntax
class ElgamalErrorEventParams(object): @property def error_code() -> int: ... @property def description() -> str: ... # In class Elgamal: @property def on_error() -> Callable[[ElgamalErrorEventParams], None]: ... @on_error.setter def on_error(event_hook: Callable[[ElgamalErrorEventParams], None]) -> None: ...
Remarks
The on_error event is fired in case of exceptional conditions during message processing. Normally the class fails with an error.
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.
Elgamal Config Settings
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 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| KeySize: The size, in bits, of the secret key.This specifies the size, in bits, of the secret key. The minimum key size for Elgamal is 512. The maximum key size is 4096. Note that large values such as 4096 will impact performance. The default value is 1024. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Base Config Settings | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| BuildInfo: Information about the product's build.When queried, this setting will return a string containing information about the product's build. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| CodePage:
The system code page used for Unicode to Multibyte translations.The default code page is Unicode UTF-8 (65001).
The following is a list of valid code page identifiers:
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LicenseInfo:
Information about the current license.When queried, this setting will return a string containing information about the license this instance of a class is using. It will return the following information:
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| ProcessIdleEvents: Whether the class uses its internal event loop to process events when the main thread is idle.If set to False, the class will not fire internal idle events. Set this to False to use the class in a background thread on Mac OS. By default, this setting is True. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| SelectWaitMillis: The length of time in milliseconds the class will wait when DoEvents is called if there are no events to process.If there are no events to process when do_events is called, the class will wait for the amount of time specified here before returning. The default value is 20. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| UseInternalSecurityAPI: Tells the class whether or not to use the system security libraries or an internal implementation. By default the class will use the system security libraries to perform cryptographic functions where applicable. Setting this to True tells the class to use the internal implementation instead of using the system's security API. |
Elgamal Errors
Elgamal Errors
| 102 No Key specified. | |
| 104 Cannot read or write file. | |
| 105 key parameters incorrect. | |
| 111 OutputFile already exists and Overwrite is False. | |
| 112 Invalid length of input message. | |
| 304 Cannot write file. | |
| 305 Cannot read file. | |
| 306 Cannot create file. | |
| 1301 Specified ElGamal parameters are invalid. | |
| 1302 Missing the data to encrypt/decrypt. | |
| 1303 Public key must be specified. | |
| 1304 Key must be specified. | |
| 1305 Invalid cipher length. The data may not have been encrypted with the public key corresponding to the specified private key data. | |
| 1306 Invalid cipher text. The data may not have been encrypted with the public key corresponding to the specified private key data. | |
| 1307 Inadequate padding. The data may not have been encrypted with the public key corresponding to the specified private key data. | |
| 1308 Missing delimiter. The data may not have been encrypted with the public key corresponding to the specified private key data. | |
| 1309 Message too long. |