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@@ -1,393 +0,0 @@
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-#!/usr/bin/env python
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-# SPDX-FileCopyrightText: 2020-2022 Espressif Systems (Shanghai) CO LTD
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-# SPDX-License-Identifier: Apache-2.0
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-import argparse
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-import hashlib
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-import hmac
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-import json
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-import os
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-import struct
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-import subprocess
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-import sys
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-
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-from cryptography.hazmat.backends import default_backend
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-from cryptography.hazmat.primitives import serialization
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-from cryptography.hazmat.primitives.asymmetric import rsa
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-from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
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-from cryptography.utils import int_to_bytes
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-
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-try:
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- import nvs_partition_gen as nvs_gen
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-except ImportError:
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- idf_path = os.getenv('IDF_PATH')
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- if not idf_path or not os.path.exists(idf_path):
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- raise Exception('IDF_PATH not found')
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- sys.path.insert(0, os.path.join(idf_path, 'components', 'nvs_flash', 'nvs_partition_generator'))
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- import nvs_partition_gen as nvs_gen
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-
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-# Check python version is proper or not to avoid script failure
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-assert sys.version_info >= (3, 6, 0), 'Python version too low.'
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-
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-esp_ds_data_dir = 'esp_ds_data'
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-# hmac_key_file is generated when HMAC_KEY is calculated, it is used when burning HMAC_KEY to efuse
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-hmac_key_file = esp_ds_data_dir + '/hmac_key.bin'
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-# csv and bin filenames are default filenames for nvs partition files created with this script
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-csv_filename = esp_ds_data_dir + '/pre_prov.csv'
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-bin_filename = esp_ds_data_dir + '/pre_prov.bin'
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-expected_json_path = os.path.join('build', 'config', 'sdkconfig.json')
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-# Targets supported by the script
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-supported_targets = {'esp32s2', 'esp32c3', 'esp32s3'}
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-supported_key_size = {'esp32s2':[1024, 2048, 3072, 4096], 'esp32c3':[1024, 2048, 3072], 'esp32s3':[1024, 2048, 3072, 4096]}
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-
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-
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-# @return
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-# on success idf_target - value of the IDF_TARGET read from build/config/sdkconfig.json
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-# on failure None
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-def get_idf_target():
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- if os.path.exists(expected_json_path):
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- sdkconfig = json.load(open(expected_json_path))
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- idf_target_read = sdkconfig['IDF_TARGET']
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- return idf_target_read
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- else:
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- print('ERROR: IDF_TARGET has not been set for the supported targets,'
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- "\nplase execute command \"idf.py set-target {TARGET}\" in the example directory")
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- return None
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-
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-
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-def load_privatekey(key_file_path, password=None):
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- key_file = open(key_file_path, 'rb')
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- key = key_file.read()
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- key_file.close()
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- return serialization.load_pem_private_key(key, password=password, backend=default_backend())
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-
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-
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-def number_as_bytes(number, pad_bits=None):
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- """
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- Given a number, format as a little endian array of bytes
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- """
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- result = int_to_bytes(number)[::-1]
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- while pad_bits is not None and len(result) < (pad_bits // 8):
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- result += b'\x00'
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- return result
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-
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-
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-# @return
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-# c : ciphertext_c
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-# iv : initialization vector
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-# key_size : key size of the RSA private key in bytes.
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-# @input
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-# privkey : path to the RSA private key
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-# priv_key_pass : path to the RSA privaete key password
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-# hmac_key : HMAC key value ( to calculate DS params)
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-# idf_target : The target chip for the script (e.g. esp32s2, esp32c3, esp32s3)
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-# @info
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-# The function calculates the encrypted private key parameters.
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-# Consult the DS documentation (available for the ESP32-S2) in the esp-idf programming guide for more details about the variables and calculations.
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-def calculate_ds_parameters(privkey, priv_key_pass, hmac_key, idf_target):
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- private_key = load_privatekey(privkey, priv_key_pass)
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- if not isinstance(private_key, rsa.RSAPrivateKey):
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- print('ERROR: Only RSA private keys are supported')
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- sys.exit(-1)
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- if hmac_key is None:
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- print('ERROR: hmac_key cannot be None')
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- sys.exit(-2)
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-
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- priv_numbers = private_key.private_numbers()
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- pub_numbers = private_key.public_key().public_numbers()
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- Y = priv_numbers.d
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- M = pub_numbers.n
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- key_size = private_key.key_size
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- if key_size not in supported_key_size[idf_target]:
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- print('ERROR: Private key size {0} not supported for the target {1},\nthe supported key sizes are {2}'
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- .format(key_size, idf_target, str(supported_key_size[idf_target])))
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- sys.exit(-1)
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-
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- iv = os.urandom(16)
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-
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- rr = 1 << (key_size * 2)
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- rinv = rr % pub_numbers.n
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- mprime = - rsa._modinv(M, 1 << 32)
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- mprime &= 0xFFFFFFFF
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- length = key_size // 32 - 1
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-
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- # get max supported key size for the respective target
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- max_len = max(supported_key_size[idf_target])
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- aes_key = hmac.HMAC(hmac_key, b'\xFF' * 32, hashlib.sha256).digest()
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-
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- md_in = number_as_bytes(Y, max_len) + \
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- number_as_bytes(M, max_len) + \
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- number_as_bytes(rinv, max_len) + \
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- struct.pack('<II', mprime, length) + \
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- iv
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-
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- # expected_len = max_len_Y + max_len_M + max_len_rinv + (mprime + length packed (8 bytes))+ iv (16 bytes)
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- expected_len = (max_len / 8) * 3 + 8 + 16
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- assert len(md_in) == expected_len
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- md = hashlib.sha256(md_in).digest()
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- # In case of ESP32-S2
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- # Y4096 || M4096 || Rb4096 || M_prime32 || LENGTH32 || MD256 || 0x08*8
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- # In case of ESP32-C3
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- # Y3072 || M3072 || Rb3072 || M_prime32 || LENGTH32 || MD256 || 0x08*8
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- p = number_as_bytes(Y, max_len) + \
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- number_as_bytes(M, max_len) + \
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- number_as_bytes(rinv, max_len) + \
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- md + \
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- struct.pack('<II', mprime, length) + \
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- b'\x08' * 8
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-
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- # expected_len = max_len_Y + max_len_M + max_len_rinv + md (32 bytes) + (mprime + length packed (8bytes)) + padding (8 bytes)
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- expected_len = (max_len / 8) * 3 + 32 + 8 + 8
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- assert len(p) == expected_len
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-
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- cipher = Cipher(algorithms.AES(aes_key), modes.CBC(iv), backend=default_backend())
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- encryptor = cipher.encryptor()
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- c = encryptor.update(p) + encryptor.finalize()
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- return c, iv, key_size
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-
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-
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-# @info
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-# The function makes use of the "espefuse.py" script to read the efuse summary
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-def efuse_summary(args, idf_target):
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- os.system('python $IDF_PATH/components/esptool_py/esptool/espefuse.py --chip {0} -p {1} summary'.format(idf_target, (args.port)))
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-
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-
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-# @info
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-# The function makes use of the "espefuse.py" script to burn the HMAC key on the efuse.
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-def efuse_burn_key(args, idf_target):
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- # In case of a development (default) usecase we disable the read protection.
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- key_block_status = '--no-read-protect'
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-
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- if args.production is True:
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- # Whitespace character will have no additional effect on the command and
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- # read protection will be enabled as the default behaviour of the command
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- key_block_status = ' '
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-
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- os.system('python $IDF_PATH/components/esptool_py/esptool/espefuse.py --chip {0} -p {1} burn_key '
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- '{2} {3} HMAC_DOWN_DIGITAL_SIGNATURE {4}'
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- .format((idf_target), (args.port), ('BLOCK_KEY' + str(args.efuse_key_id)), (hmac_key_file), (key_block_status)))
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-
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-
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-# @info
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-# Generate a custom csv file of encrypted private key parameters.
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-# The csv file is required by the nvs_partition_generator utility to create the nvs partition.
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-def generate_csv_file(c, iv, hmac_key_id, key_size, csv_file):
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-
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- with open(csv_file, 'wt', encoding='utf8') as f:
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- f.write('# This is a generated csv file containing required parameters for the Digital Signature operation\n')
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- f.write('key,type,encoding,value\nesp_ds_ns,namespace,,\n')
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- f.write('esp_ds_c,data,hex2bin,%s\n' % (c.hex()))
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- f.write('esp_ds_iv,data,hex2bin,%s\n' % (iv.hex()))
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- f.write('esp_ds_key_id,data,u8,%d\n' % (hmac_key_id))
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- f.write('esp_ds_rsa_len,data,u16,%d\n' % (key_size))
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-
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-
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-class DefineArgs(object):
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- def __init__(self, attributes):
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- for key, value in attributes.items():
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- self.__setattr__(key, value)
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-
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-
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-# @info
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-# This function uses the nvs_partition_generater utility
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-# to generate the nvs partition of the encrypted private key parameters.
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-def generate_nvs_partition(input_filename, output_filename):
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-
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- nvs_args = DefineArgs({
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- 'input': input_filename,
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- 'outdir': os.getcwd(),
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- 'output': output_filename,
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- 'size': hex(0x3000),
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- 'version': 2,
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- 'keyfile':None,
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- })
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-
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- nvs_gen.generate(nvs_args, is_encr_enabled=False, encr_key=None)
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-
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-
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-# @return
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-# The json formatted summary of the efuse.
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-def get_efuse_summary_json(args, idf_target):
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- _efuse_summary = None
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- try:
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- _efuse_summary = subprocess.check_output(('python $IDF_PATH/components/esptool_py/esptool/espefuse.py '
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- '--chip {0} -p {1} summary --format json'.format(idf_target, (args.port))), shell=True)
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- except subprocess.CalledProcessError as e:
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- print((e.output).decode('UTF-8'))
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- sys.exit(-1)
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-
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- _efuse_summary = _efuse_summary.decode('UTF-8')
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- # Remove everything before actual json data from efuse_summary command output.
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- _efuse_summary = _efuse_summary[_efuse_summary.find('{'):]
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- try:
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- _efuse_summary_json = json.loads(_efuse_summary)
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- except json.JSONDecodeError:
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- print('ERROR: failed to parse the json output')
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- sys.exit(-1)
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- return _efuse_summary_json
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-
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-
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-# @return
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-# on success: 256 bit HMAC key present in the given key_block (args.efuse_key_id)
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-# on failure: None
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-# @info
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-# This function configures the provided efuse key_block.
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-# If the provided efuse key_block is empty the function generates a new HMAC key and burns it in the efuse key_block.
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-# If the key_block already contains a key the function reads the key from the efuse key_block
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-def configure_efuse_key_block(args, idf_target):
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- efuse_summary_json = get_efuse_summary_json(args, idf_target)
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- key_blk = 'BLOCK_KEY' + str(args.efuse_key_id)
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- key_purpose = 'KEY_PURPOSE_' + str(args.efuse_key_id)
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-
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- kb_writeable = efuse_summary_json[key_blk]['writeable']
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- kb_readable = efuse_summary_json[key_blk]['readable']
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- hmac_key_read = None
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-
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- # If the efuse key block is writable (empty) then generate and write
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- # the new hmac key and check again
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- # If the efuse key block is not writable (already contains a key) then check if it is redable
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- if kb_writeable is True:
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- print('Provided key block (KEY BLOCK %1d) is writable\n Generating a new key and burning it in the efuse..\n' % (args.efuse_key_id))
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-
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- new_hmac_key = os.urandom(32)
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- with open(hmac_key_file, 'wb') as key_file:
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- key_file.write(new_hmac_key)
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- # Burn efuse key
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- efuse_burn_key(args, idf_target)
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- if args.production is False:
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- # Read fresh summary of the efuse to read the key value from efuse.
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- # If the key read from efuse matches with the key generated
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- # on host then burn_key operation was successfull
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- new_efuse_summary_json = get_efuse_summary_json(args, idf_target)
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- hmac_key_read = new_efuse_summary_json[key_blk]['value']
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- print(hmac_key_read)
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- hmac_key_read = bytes.fromhex(hmac_key_read)
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- if new_hmac_key == hmac_key_read:
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- print('Key was successfully written to the efuse (KEY BLOCK %1d)' % (args.efuse_key_id))
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- else:
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- print('ERROR: Failed to burn the hmac key to efuse (KEY BLOCK %1d),'
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- '\nPlease execute the script again using a different key id' % (args.efuse_key_id))
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- return None
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- else:
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- new_efuse_summary_json = get_efuse_summary_json(args, idf_target)
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- if new_efuse_summary_json[key_purpose]['value'] != 'HMAC_DOWN_DIGITAL_SIGNATURE':
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- print('ERROR: Failed to verify the key purpose of the key block{})'.format(args.efuse_key_id))
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- return None
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- hmac_key_read = new_hmac_key
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- else:
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- # If the efuse key block is redable, then read the key from efuse block and use it for encrypting the RSA private key parameters.
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- # If the efuse key block is not redable or it has key purpose set to a different
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- # value than "HMAC_DOWN_DIGITAL_SIGNATURE" then we cannot use it for DS operation
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- if kb_readable is True:
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- if efuse_summary_json[key_purpose]['value'] == 'HMAC_DOWN_DIGITAL_SIGNATURE':
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- print('Provided efuse key block (KEY BLOCK %1d) already contains a key with key_purpose=HMAC_DOWN_DIGITAL_SIGNATURE,'
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- '\nusing the same key for encrypting the private key data...\n' % (args.efuse_key_id))
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- hmac_key_read = efuse_summary_json[key_blk]['value']
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- hmac_key_read = bytes.fromhex(hmac_key_read)
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- if args.keep_ds_data is True:
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- with open(hmac_key_file, 'wb') as key_file:
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- key_file.write(hmac_key_read)
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- else:
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- print('ERROR: Provided efuse key block ((KEY BLOCK %1d)) contains a key with key purpose different'
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- 'than HMAC_DOWN_DIGITAL_SIGNATURE,\nplease execute the script again with a different value of the efuse key id.' % (args.efuse_key_id))
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- return None
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- else:
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- print('ERROR: Provided efuse key block (KEY BLOCK %1d) is not readable and writeable,'
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- '\nplease execute the script again with a different value of the efuse key id.' % (args.efuse_key_id))
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- return None
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-
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- # Return the hmac key burned into the efuse
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- return hmac_key_read
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-
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-
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-def cleanup(args):
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- if args.keep_ds_data is False:
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- if os.path.exists(hmac_key_file):
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- os.remove(hmac_key_file)
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- if os.path.exists(csv_filename):
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- os.remove(csv_filename)
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-
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-
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-def main():
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- parser = argparse.ArgumentParser(description='''Generate an HMAC key and burn it in the desired efuse key block (required for Digital Signature),
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- Generates an NVS partition containing the encrypted private key parameters from the client private key.
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- ''')
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-
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- parser.add_argument(
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- '--private-key',
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- dest='privkey',
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- default='client.key',
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- metavar='relative/path/to/client-priv-key',
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- help='relative path to client private key')
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-
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- parser.add_argument(
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- '--pwd', '--password',
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- dest='priv_key_pass',
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- metavar='[password]',
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- help='the password associated with the private key')
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-
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- parser.add_argument(
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- '--summary',
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- dest='summary',action='store_true',
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- help='Provide this option to print efuse summary of the chip')
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-
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- parser.add_argument(
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- '--efuse_key_id',
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- dest='efuse_key_id', type=int, choices=range(1,6),
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- metavar='[key_id] ',
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- default=1,
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- help='Provide the efuse key_id which contains/will contain HMAC_KEY, default is 1')
|
|
|
-
|
|
|
- parser.add_argument(
|
|
|
- '--port', '-p',
|
|
|
- dest='port',
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|
|
- metavar='[port]',
|
|
|
- required=True,
|
|
|
- help='UART com port to which the ESP device is connected')
|
|
|
-
|
|
|
- parser.add_argument(
|
|
|
- '--keep_ds_data_on_host','-keep_ds_data',
|
|
|
- dest='keep_ds_data', action='store_true',
|
|
|
- help='Keep encrypted private key data and key on host machine for testing purpose')
|
|
|
-
|
|
|
- parser.add_argument(
|
|
|
- '--production', '-prod',
|
|
|
- dest='production', action='store_true',
|
|
|
- help='Enable production configurations. e.g.keep efuse key block read protection enabled')
|
|
|
-
|
|
|
- args = parser.parse_args()
|
|
|
-
|
|
|
- idf_target = get_idf_target()
|
|
|
- if idf_target not in supported_targets:
|
|
|
- if idf_target is not None:
|
|
|
- print('ERROR: The script does not support the target %s' % idf_target)
|
|
|
- sys.exit(-1)
|
|
|
- idf_target = str(idf_target)
|
|
|
-
|
|
|
- if args.summary is not False:
|
|
|
- efuse_summary(args, idf_target)
|
|
|
- sys.exit(0)
|
|
|
-
|
|
|
- if (os.path.exists(args.privkey) is False):
|
|
|
- print('ERROR: The provided private key file does not exist')
|
|
|
- sys.exit(-1)
|
|
|
-
|
|
|
- if (os.path.exists(esp_ds_data_dir) is False):
|
|
|
- os.makedirs(esp_ds_data_dir)
|
|
|
-
|
|
|
- # Burn hmac_key on the efuse block (if it is empty) or read it
|
|
|
- # from the efuse block (if the efuse block already contains a key).
|
|
|
- hmac_key_read = configure_efuse_key_block(args, idf_target)
|
|
|
- if hmac_key_read is None:
|
|
|
- sys.exit(-1)
|
|
|
-
|
|
|
- # Calculate the encrypted private key data along with all other parameters
|
|
|
- c, iv, key_size = calculate_ds_parameters(args.privkey, args.priv_key_pass, hmac_key_read, idf_target)
|
|
|
-
|
|
|
- # Generate csv file for the DS data and generate an NVS partition.
|
|
|
- generate_csv_file(c, iv, args.efuse_key_id, key_size, csv_filename)
|
|
|
- generate_nvs_partition(csv_filename, bin_filename)
|
|
|
- cleanup(args)
|
|
|
-
|
|
|
-
|
|
|
-if __name__ == '__main__':
|
|
|
- main()
|