Files
SDK_GD32W51x/scripts/imgtool/imglib/keys/ed25519.py
2023-05-18 18:53:00 +08:00

126 lines
4.1 KiB
Python

"""
ECDSA key management
"""
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import ed25519
from cryptography import x509
from cryptography.x509.oid import NameOID
from cryptography.hazmat.primitives import hashes
from .general import KeyClass
class Ed25519UsageError(Exception):
pass
class Ed25519Public(KeyClass):
def __init__(self, key):
self.key = key
def shortname(self):
return "ed25519"
def _unsupported(self, name):
raise Ed25519UsageError("Operation {} requires private key".format(name))
def _get_public(self):
return self.key
def get_public_bytes(self):
# The key is embedded into MBUboot in "SubjectPublicKeyInfo" format
return self._get_public().public_bytes(
encoding=serialization.Encoding.Raw,
format=serialization.PublicFormat.Raw)
def export_private(self, path, passwd=None):
self._unsupported('export_private')
def export_public(self, path):
"""Write the public key to the given file."""
pem = self._get_public().public_bytes(
encoding=serialization.Encoding.PEM,
format=serialization.PublicFormat.SubjectPublicKeyInfo)
with open(path, 'wb') as f:
f.write(pem)
def sig_type(self):
return "ED25519"
def sig_tlv(self):
return "ED25519"
def sig_len(self):
return 64
class Ed25519(Ed25519Public):
"""
Wrapper around an ECDSA private key.
"""
def __init__(self, key):
"""key should be an instance of EllipticCurvePrivateKey"""
self.key = key
@staticmethod
def generate():
pk = ed25519.Ed25519PrivateKey.generate()
return Ed25519(pk)
def _get_public(self):
return self.key.public_key()
def export_private(self, path, passwd=None):
"""
Write the private key to the given file, protecting it with the
optional password.
"""
if passwd is None:
enc = serialization.NoEncryption()
else:
enc = serialization.BestAvailableEncryption(passwd)
pem = self.key.private_bytes(
encoding=serialization.Encoding.PEM,
format=serialization.PrivateFormat.PKCS8,
encryption_algorithm=enc)
with open(path, 'wb') as f:
f.write(pem)
def sign_digest(self, digest):
"""Return the actual signature"""
return self.key.sign(data=digest)
def verify_digest(self, signature, digest):
"""Verify that signature is valid for given digest"""
k = self.key
if isinstance(self.key, ed25519.Ed25519PrivateKey):
k = self.key.public_key()
return k.verify(signature=signature, data=digest)
def create_csr(self, path):
# Generate a CSR
csr = x509.CertificateSigningRequestBuilder().subject_name(x509.Name([
# Provide various details about who we are.
x509.NameAttribute(NameOID.COUNTRY_NAME, u"CN"),
x509.NameAttribute(NameOID.STATE_OR_PROVINCE_NAME, u"Jiangsu"),
x509.NameAttribute(NameOID.LOCALITY_NAME, u"Suzhou"),
x509.NameAttribute(NameOID.ORGANIZATION_NAME, u"My Company"),
x509.NameAttribute(NameOID.COMMON_NAME, u"gigadevice.com/"),
])).add_extension(
x509.SubjectAlternativeName([
# Describe what sites we want this certificate for.
x509.DNSName(u"gigadevice.com"),
x509.DNSName(u"www.gigadevice.com"),
x509.DNSName(u"subdomain.gigadevice.com"),
]),
critical=False,
# Sign the CSR with our private key.
).sign(self.key, hashes.SHA256(), default_backend())
# Write our CSR out to disk. "path/to/csr.pem"
with open(path, "wb") as f:
f.write(csr.public_bytes(serialization.Encoding.PEM))