qkd_key_rate.base.parity_strategy module

Base class for ParityStrategy object.

class qkd_key_rate.base.parity_strategy.ParityStrategy(error_rate, sampling_fraction=0.5, number_of_passes=10, switch_after_pass=None)

Bases: object

Parity strategy to be used in the Cascade protocol.

In the Cascade protocol, for efficiency reasons, we may change the strategy of our blocks after some passes. This class deals with the parity strategy

__init__(error_rate, sampling_fraction=0.5, number_of_passes=10, switch_after_pass=None)

Parameters:

• error_rate (float) – An estimate of the error rate in the message

• sampling_fraction (float) – Fraction of the string that is sampled after switching strategies

• number_of_passes (int) – Total number of Cascade iterations

• switch_after_pass (Optional[int]) – After which pass we switch the strategy

calculate_message_parity_strategy(message_size)

Sets the parity strategy

Initial strategy is to double the block size in each subsequent pass. After some number of passes, we may change the strategy by randomly sampling bits from the message in new blocks.

Parameters:

message_size (int) – Size of the message for which to calculate the parity strategy

Returns:

The block size and number of blocks for each pass

Return type:

size_blocks_parities

get_start_block_size()

Determine starting block size.

Return type:

int

Returns:

The largest block size that is compatible with given error-rate