Additive Scrambler

Scramble an input stream using a Linear Feedback Shift Register (LFSR).

This block scrambles up to 8 bits per byte of the input data stream, starting at the LSB. The scrambler works by XORing the incoming bit stream by the output of the LFSR. Optionally, after bits have been processed, the shift register is reset to the value. This allows processing fixed length vectors of samples.

Alternatively, the LFSR can be reset using a reset tag to scramble variable length vectors. However, it cannot be reset between bytes.

For details on configuring the LFSR, see gr::digital::lfsr.

Parameters

(R): Run-time adjustable

Mask

Polynomial mask for LFSR

Seed

Initial shift register contents

Length

Shift register length

Count

Number of bytes after which shift register is reset, 0=never

Bits per byte

Number of bits per byte

Reset tag key

When a tag with this key is detected, the shift register is reset (when this is set, count is ignored!)

Example Flowgraph

Insert description of flowgraph here, then show a screenshot of the flowgraph and the output if there is an interesting GUI. Currently we have no standard method of uploading the actual flowgraph to the wiki or git repo, unfortunately. The plan is to have an example flowgraph showing how the block might be used, for every block, and the flowgraphs will live in the git repo.

Source Files

C++ files

TODO

Header files

TODO

Public header files

TODO

Block definition

TODO