HashFunction Class

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The HashFunction class implements a wide variety of algorithms for message hashing.

Syntax

class secureblackbox.HashFunction

Remarks

HashFunction allows you to hash messages using a variety of industry standard hashing algorithms. Algorithms of both Hash and HMAC type are supported.

You can feed your data to HashFunction in one go, or in chunks. Use hash method to initialize the hash function, pass the buffer, and calculate the hash in one line of code. Alternatively, use reset, update, and finish in sequence to perform each of those steps individually. You can call update (and its update_file and update_stream variants) repeatedly between reset and finish, effectively passing the data in a number of portions: // Feeding the data in one go: Hashfunction hf = new Hashfunction(); hf.Algorithm = "SHA256"; byte[] hash = hf.Hash(buffer); // Feeding data chunk by chunk: Hashfunction hf = new Hashfunction(); hf.Algorithm = "SHA256"; hf.Reset(); hf.Update(buffer1); hf.Update(buffer2); hf.Update(buffer3); byte[] hash = hf.Finish();

To use keyed HMAC, you need to provide the secret key first. Use CryptoKeyManager to create and initialize the key object: Cryptokeymanager km = new Cryptokeymanager(); km.ImportBytes(hmacKey, Constants.kffDER, "SHA256", "", "", Constants.ktSecret); Hashfunction hf = new Hashfunction(); hf.Algorithm = "SHA256"; hf.Key = km.Key; byte[] hash = hf.Hash(buffer);

Use output_encoding to set the desired encoding method.

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

The hash algorithm to use when hashing data.

Syntax

def get_algorithm() -> str: ...
def set_algorithm(value: str) -> None: ...

algorithm = property(get_algorithm, set_algorithm)

Default Value

"SHA256"

Remarks

fips_mode Property

Reserved.

Syntax

def get_fips_mode() -> bool: ...
def set_fips_mode(value: bool) -> None: ...

fips_mode = property(get_fips_mode, set_fips_mode)

Default Value

FALSE

Remarks

This property is reserved for future use.

json_key_header_params Property

Contains key header parameters.

Syntax

def get_json_key_header_params() -> str: ...
def set_json_key_header_params(value: str) -> None: ...

json_key_header_params = property(get_json_key_header_params, set_json_key_header_params)

Default Value

"kid"

Remarks

Contains key header parameters.

json_protected_header Property

Provides access to the header being protected.

Syntax

def get_json_protected_header() -> str: ...
def set_json_protected_header(value: str) -> None: ...

json_protected_header = property(get_json_protected_header, set_json_protected_header)

Default Value

""

Remarks

Provides access to the header being protected.

json_unprotected_header Property

Provides access to the unprotected part of the header.

Syntax

def get_json_unprotected_header() -> str: ...
def set_json_unprotected_header(value: str) -> None: ...

json_unprotected_header = property(get_json_unprotected_header, set_json_unprotected_header)

Default Value

""

Remarks

Provides access to the unprotected part of the header.

json_unprotected_header_params Property

Contains unprotected header parameters.

Syntax

def get_json_unprotected_header_params() -> str: ...
def set_json_unprotected_header_params(value: str) -> None: ...

json_unprotected_header_params = property(get_json_unprotected_header_params, set_json_unprotected_header_params)

Default Value

""

Remarks

Contains unprotected header parameters.

key_handle Property

Allows to get or set a 'handle', a unique identifier of the underlying property object.

Syntax

def get_key_handle() -> int: ...
def set_key_handle(value: int) -> None: ...

key_handle = property(get_key_handle, set_key_handle)

Default Value

0

Remarks

Allows to get or set a 'handle', a unique identifier of the underlying property object. Use this property to assign objects of the same type in a quicker manner, without copying them fieldwise.

When you pass a handle of one object to another, the source object is copied to the destination rather than assigned. It is safe to get rid of the original object after such operation. pdfSigner.setSigningCertHandle(certMgr.getCertHandle());

key_key Property

The byte array representation of the key.

Syntax

def get_key_key() -> bytes: ...

key_key = property(get_key_key, None)

Remarks

The byte array representation of the key. This may not be available for non-key_exportable keys.

This property is read-only.

output_encoding Property

The encoding to use for the output data.

Syntax

def get_output_encoding() -> int: ...
def set_output_encoding(value: int) -> None: ...

output_encoding = property(get_output_encoding, set_output_encoding)

Default Value

0

Remarks

Use this property to configure the type of encoding to be used for the output data.

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.

do_action Method

Performs an additional action.

Syntax

def do_action(action_id: str, action_params: str) -> str: ...

Remarks

do_action is a generic method available in every class. It is used to perform an additional action introduced after the product major release. The list of actions is not fixed, and may be flexibly extended over time.

The unique identifier (case insensitive) of the action is provided in the ActionID parameter.

ActionParams contains the value of a single parameter, or a list of multiple parameters for the action in the form of PARAM1=VALUE1;PARAM2=VALUE2;....

finish Method

Completes the hash and returns the resulting message digest.

Syntax

def finish() -> bytes: ...

Remarks

This method finalizes the hashing operation and returns the message digest of the input data. Use it in conjuction with reset and update methods to process data in chunks.

hash Method

Calculates a message digest over a byte array.

Syntax

def hash(buffer: bytes) -> bytes: ...

Remarks

This method calculates and returns a message digest over the content of Buffer. This is a quick way to calculate a hash over a byte array in one go.

hash_file Method

Calculates a message digest over data contained in a file.

Syntax

def hash_file(source_file: str) -> bytes: ...

Remarks

This method calculates and returns a message digest over the data contained in file SourceFile. This is a quick way to calculate a hash over a file content in one go.

hash_stream Method

Calculates a message digest over data contained in a stream.

Syntax

def hash_stream() -> bytes: ...

Remarks

This method calculates a message digest over the data contained in input_stream. This is a quick way of calculating a message data over a stream content in one go.

reset Method

Resets the hash function context.

Syntax

def reset() -> None: ...

Remarks

reset resets the context of the hash function, discarding any data passed to it previously.

Use this method to restart the hash calculation process from scratch.

This method does not affect one-go methods like hash or hash_stream; they reset the hash function context automatically.

update Method

Feeds a chunk of data to the hash function.

Syntax

def update(buffer: bytes) -> None: ...

Remarks

This method feeds Buffer to the hash function. Call this method repeatedly to pass your data to the hash function chunk by chunk.

Remember to initialize the hash function with an reset call before starting to feed data with this method. After the whole volume of data has been sent, complete the calculation and obtain the resulting message digest with a finish call.

update_file Method

Feeds the contents of a file to the hash function.

Syntax

def update_file(source_file: str) -> None: ...

Remarks

Call this method to pass the contents of a file to the hash function. You can call this function repeatedly and mix it with update to feed the hash function with many separate chunks of data.

Remember to initialize the hash function with an reset call before starting hashing the data. Once all the data chunks have been submitted, finalize the hash function and obtain the resulting message digest by calling finish.

update_stream Method

Feeds the contents of a stream to the hash function.

Syntax

def update_stream() -> None: ...

Remarks

Call this method to pass the contents of a stream to the hash function. You can call this function repeatedly and mix it with update to feed the hash function with many separate chunks of data.

Remember to initialize the hash function with an reset call before starting hashing the data. Once all the data chunks have been submitted, finalize the hash function and obtain the resulting message digest by calling finish.

on_error Event

Informs about errors during cryptographic operations.

Syntax

class HashFunctionErrorEventParams(object):
  @property
  def error_code() -> int: ...

  @property
  def description() -> str: ...

# In class HashFunction:
@property
def on_error() -> Callable[[HashFunctionErrorEventParams], None]: ...
@on_error.setter
def on_error(event_hook: Callable[[HashFunctionErrorEventParams], None]) -> None: ...

Remarks

Class fires this event if an error happens during a cryptographic operation.

ErrorCode contains an error code and Description contains a textual description of the error that happened.

on_notification Event

This event notifies the application about an underlying control flow event.

Syntax

class HashFunctionNotificationEventParams(object):
  @property
  def event_id() -> str: ...

  @property
  def event_param() -> str: ...

# In class HashFunction:
@property
def on_notification() -> Callable[[HashFunctionNotificationEventParams], None]: ...
@on_notification.setter
def on_notification(event_hook: Callable[[HashFunctionNotificationEventParams], None]) -> None: ...

Remarks

The class fires this event to let the application know about some event, occurrence, or milestone in the class. For example, it may fire to report completion of the document processing. The list of events being reported is not fixed, and may be flexibly extended over time.

The unique identifier of the event is provided in the EventID parameter. EventParam contains any parameters accompanying the occurrence. Depending on the type of the class, the exact action it is performing, or the document being processed, one or both may be omitted.

HashFunction 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.

HashFunction Config Settings

Base Config Settings

HashFunction Errors

HashFunction Errors