[device] CW340 support

This PR adds experimental CW340 support with a minimal running
capture script.

Signed-off-by: Pascal Nasahl <nasahlpa@lowrisc.org>

Author: nasahlpa

cw/cw340_aes_sca.py

@@ -0,0 +1,154 @@
+#!/usr/bin/env python3
+# Copyright lowRISC contributors.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+import binascii
+import random
+import signal
+import sys
+import time
+from datetime import datetime
+from functools import partial
+from pathlib import Path
+
+import chipwhisperer as cw
+import numpy as np
+import yaml
+from Crypto.Cipher import AES
+from tqdm import tqdm
+
+from util import device, plot, trace_util
+
+def setup_target(scope):
+    target = cw.target(scope)
+    target.baud = int(115200)
+    target.flush()
+    version = None
+    ping_cnt = 0
+    while not version:
+        if ping_cnt == 3:
+            print("no response from target")
+            sys.exit(0)
+        target.write('v' + '\n')
+        ping_cnt += 1
+        time.sleep(0.5)
+        version = target.read().strip()
+    print(version)
+    return target
+
+def setup_scope(cfg):
+    scope = cw.scope()
+    scope.gain.db = cfg["cwfpgahusky"]["scope_gain"]
+    scope.adc.basic_mode = "rising_edge"
+    scope.clock.clkgen_src = 'extclk'
+    scope.clock.clkgen_freq = cfg["cwfpgahusky"]["pll_frequency"]
+    scope.clock.adc_mul = cfg["cwfpgahusky"]["adc_mul"]
+    scope.clock.extclk_monitor_enabled = False
+    scope.adc.samples = cfg["cwfpgahusky"]["num_samples"]
+    if cfg["cwfpgahusky"]["offset"] >= 0:
+        scope.adc.offset = cfg["cwfpgahusky"]["offset"]
+    else:
+        scope.adc.offset = 0
+        scope.adc.presamples = -cfg["cwfpgahusky"]["offset"]
+    scope.trigger.triggers = "tio4"
+    scope.io.tio1 = "serial_tx"
+    scope.io.tio2 = "serial_rx"
+    scope.io.hs2 = "disabled"
+    scope.clock.clkgen_src = 'extclk'
+    if not scope.clock.clkgen_locked:
+        print("scope.clock.clkgen is not locked")
+        sys.exit(0)
+    if not scope.clock.adc_locked:
+        print("scope.clock.adc is not locked")
+        sys.exit(0)
+    return scope
+
+def prepare_aes(cfg):
+    # Preparation of Key and plaintext generation
+    # Generate key at random based on test_random_seed (not used atm)
+    random.seed(cfg["test"]["test_random_seed"])
+    key = bytearray(cfg["test"]["key_len_bytes"])
+    for i in range(0, cfg["test"]["key_len_bytes"]):
+        key[i] = random.randint(0, 255)
+    # Load initial key and text values from cfg
+    key = bytearray(cfg["test"]["key"])
+    print(f'Using key: {binascii.b2a_hex(bytes(key))}')
+    text = bytearray(cfg["test"]["text"])
+    # Prepare generation of new texts/keys by encryption using key_for_generation
+    key_for_gen = bytearray(cfg["test"]["key_for_gen"])
+    cipher_gen = AES.new(bytes(key_for_gen), AES.MODE_ECB)
+    return key, text, key_for_gen, cipher_gen
+
+
+if __name__ == '__main__':
+    # Load configuration from file
+    with open('simple_capture_aes_sca_cw340.yaml') as f:
+        cfg = yaml.load(f, Loader=yaml.FullLoader)
+    scope = setup_scope(cfg)
+    target = setup_target(scope)
+
+    # Create ChipWhisperer project for storage of traces and metadata
+    project = cw.create_project(cfg["capture"]["project_name"], overwrite=True)
+
+    key, text, key_for_gen, cipher_gen = prepare_aes(cfg)
+
+    # Set key
+    target.simpleserial_write("k", key)
+
+    # Cipher to compute expected responses
+    cipher = AES.new(bytes(key), AES.MODE_ECB)
+
+    # Main loop for measurements with progress bar
+    for _ in tqdm(range(cfg["capture"]["num_traces"]), desc='Capturing', ncols=80):
+        scope.arm()
+
+        # Generate new text for this iteration
+        text = bytearray(cipher_gen.encrypt(text))
+        # Load text and trigger execution
+        target.simpleserial_write('p', text)
+
+        # Capture trace
+        ret = scope.capture(poll_done=False)
+        i = 0
+        while not target.is_done():
+            i += 1
+            time.sleep(0.05)
+            if i > 100:
+                print("Warning: Target did not finish operation")
+        if ret:
+            print("Warning: Timeout happened during capture")
+
+        # Get trace
+        wave = scope.get_last_trace(as_int=True)
+
+
+        # Get response from device and verify
+        response = target.simpleserial_read('r', target.output_len, ack=False)
+        if binascii.b2a_hex(response) != binascii.b2a_hex(cipher.encrypt(bytes(text))):
+            raise RuntimeError(f'Bad ciphertext: {response} != {cipher.encrypt(bytes(text))}.')
+
+        # Sanity check retrieved data (wave) and create CW Trace
+        if len(wave) >= 1:
+            trace = cw.Trace(wave, text, response, key)
+        else:
+            raise RuntimeError('Capture failed.')
+
+        # Check if ADC range has been exceeded for Husky.
+        trace_util.check_range(trace.wave, scope.adc.bits_per_sample)
+
+        # Append CW trace to CW project storage
+        project.traces.append(trace, dtype=np.uint16)
+
+    # Save metadata and entire configuration cfg to project file
+    project.settingsDict['datetime'] = datetime.now().strftime("%m/%d/%Y, %H:%M:%S")
+    project.settingsDict['cfg'] = cfg
+    sample_rate = int(round(scope.clock.adc_freq, -6))
+    project.settingsDict['sample_rate'] = sample_rate
+    project.save()
+
+    # Create and show test plot
+    if cfg["capture"]["show_plot"]:
+        plot.save_plot_to_file(project.waves, None, cfg["capture"]["plot_traces"],
+                               cfg["capture"]["trace_image_filename"], add_mean_stddev=True)
+        print(f'Created plot with {cfg["capture"]["plot_traces"]} traces: '
+              f'{Path(cfg["capture"]["trace_image_filename"]).resolve()}')

cw/simple_capture_aes_sca_cw340.yaml

@@ -0,0 +1,22 @@
+cwfpgahusky:
+  baudrate: 115200
+  output_len_bytes: 16
+  pll_frequency: 100000000
+  adc_mul: 2
+  num_segments: 1
+  num_samples: 1200
+  offset: -40
+  scope_gain: 31.5
+capture:
+  scope_select: husky
+  num_traces: 1000
+  project_name: "projects/simple_capture_aes_sca"
+  show_plot: True
+  plot_traces: 100
+  trace_image_filename: "projects/simple_capture_aes_sca_sample_traces.html"
+test:
+  key_len_bytes: 16
+  test_random_seed: 0
+  key: [0x81, 0x1E, 0x37, 0x31, 0xB0, 0x12, 0x0A, 0x78, 0x42, 0x78, 0x1E, 0x22, 0xB2, 0x5C, 0xDD, 0xF9]
+  text: [0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA]
+  key_for_gen: [0x12, 0x34, 0x56, 0x78, 0x9A, 0xBC, 0xDE, 0xF1, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xE0, 0xF0]