[sca] streamlined vertical otbn part

Signed-off-by: Michael Tempelmeier <[email protected]>

cw/capture.py

@@ -992,7 +992,7 @@ def kmac_fvsr_key_batch(ctx: typer.Context,
  capture_end(ctx.obj.cfg)
 
 
-def capture_ecdsa_secret_keygen(ot, ktp, fw_bin, pll_frequency, capture_cfg):
+def capture_otbn_vertical(ot, ktp, fw_bin, pll_frequency, capture_cfg):
  """Capture traces for ECDSA P256/P384 secret key generation.
 
  Uses a fixed seed and generates several random masks. For the corresponding
@@ -1011,14 +1011,10 @@ def capture_ecdsa_secret_keygen(ot, ktp, fw_bin, pll_frequency, capture_cfg):
  reset_firmware = False
 
  # OTBN operations are long. CW-Husky can store only 131070 samples
- # in the non-stream mode. In case we want to collect more samples,
- # we can run the operation multiple times with different adc_offset
- # values.
- # The trace from each run is kept in a section, and all sections are
- # concatenated to create the final trace.
+ # in the non-stream mode.
  fifo_size = 131070
- num_sections = capture_cfg["num_samples"] // fifo_size
- print(f"num_sections = {num_sections}")
+ if capture_cfg["num_samples"] > fifo_size:
+  raise RuntimeError('Current setup only supports up to 130k smaples')
 
  # Be sure we don't use the stream mode
  if ot.scope._is_husky:
@@ -1064,50 +1060,44 @@ def capture_ecdsa_secret_keygen(ot, ktp, fw_bin, pll_frequency, capture_cfg):
  # Loop to collect each power trace
  for _ in tqdm(range(capture_cfg["num_traces"]), desc='Capturing',
  ncols=80):
- # Create a clean array to keep each section
- waves = np.array([])
+
+ if reset_firmware:
+ ot.program_target(fw_bin, pll_frequency)
+
+ ot.scope.adc.offset = capture_cfg["offset"]
 
  # Generate a new random mask for each trace.
  mask = ktp.next_text()
  tqdm.write(f'mask = {mask.hex()}')
 
- # Loop to collect each section of the power trace
- for ii in range(num_sections):
- if reset_firmware:
- ot.program_target(fw_bin, pll_frequency)
+ # Set the seed.
+ ot.target.simpleserial_write('x', seed)
 
- # For each section ii, set the adc_offset parameter accordingly
- ot.scope.adc.offset = ii * fifo_size
+ # Check for errors.
+ err = ot.target.read()
+ if err:
+ raise RuntimeError(f'Error writing seed: {err}')
 
- # Set the seed.
- ot.target.simpleserial_write('x', seed)
-
- # Check for errors.
- err = ot.target.read()
- if err:
- raise RuntimeError(f'Error writing seed: {err}')
-
- # Arm the scope
- ot.scope.arm()
-
- # Send the mask and start the keygen operation.
- ot.target.simpleserial_write('k', mask)
+ # Arm the scope
+ ot.scope.arm()
 
- # Wait until operation is done.
- ret = ot.scope.capture(poll_done=True)
- # If getting inconsistent results (e.g. variable number of cycles),
- # adding a sufficient sleep below here appears to fix things
- # time.sleep(1) # we cannot afford 1 second per run.
- if ret:
- raise RuntimeError('Timeout during capture')
+ # Send the mask and start the keygen operation.
+ ot.target.simpleserial_write('k', mask)
 
- # Check the number of cycles where the trigger signal was high.
- cycles = ot.scope.adc.trig_count
- tqdm.write("Observed number of cycles: %d" % cycles)
+ # Wait until operation is done.
+ ret = ot.scope.capture(poll_done=True)
+ # TODO: change this
+ # If getting inconsistent results (e.g. variable number of cycles),
+ # adding a sufficient sleep below here appears to fix things
+ # time.sleep(1) # we cannot afford 1 second per run.
+ if ret:
+ raise RuntimeError('Timeout during capture')
 
- # Append the section into the waves array
- waves = np.append(waves, ot.scope.get_last_trace(as_int=True))
+ # Check the number of cycles where the trigger signal was high.
+ cycles = ot.scope.adc.trig_count
+ tqdm.write("Observed number of cycles: %d" % cycles)
 
+ waves = ot.scope.get_last_trace(as_int=True)
  # Read the output, unmask the key, and check if it matches
  # expectations.
  share0 = ot.target.simpleserial_read("r", seed_bytes, ack=False)
@@ -1133,7 +1123,7 @@ def capture_ecdsa_secret_keygen(ot, ktp, fw_bin, pll_frequency, capture_cfg):
 
 
 @app_capture.command()
-def ecdsa_secret_keygen(ctx: typer.Context,
+def otbn_vertical(ctx: typer.Context,
  num_traces: int = opt_num_traces,
  plot_traces: int = opt_plot_traces):
  """Capture ECDSA secret key generation traces."""
@@ -1160,7 +1150,7 @@ def ecdsa_secret_keygen(ctx: typer.Context,
  )
 
  # Call the capture loop
- capture_ecdsa_secret_keygen(ctx.obj.ot,
+ capture_otbn_vertical(ctx.obj.ot,
  ctx.obj.ktp,
  ctx.obj.cfg["device"]["fw_bin"],
  ctx.obj.cfg["device"]["pll_frequency"],