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import binascii
from . import der
from ._compat import compat26_str, int_to_bytes
_SSH_ED25519 = b"ssh-ed25519"
_SK_MAGIC = b"openssh-key-v1\0"
_NONE = b"none"
def _get_key_type(name):
if name == "Ed25519":
return _SSH_ED25519
else:
raise ValueError("Unsupported key type")
class _Serializer:
def __init__(self):
self.bytes = b""
def put_raw(self, val):
self.bytes += val
def put_u32(self, val):
self.bytes += int_to_bytes(val, length=4, byteorder="big")
def put_str(self, val):
self.put_u32(len(val))
self.bytes += val
def put_pad(self, blklen=8):
padlen = blklen - (len(self.bytes) % blklen)
self.put_raw(bytearray(range(1, 1 + padlen)))
def encode(self):
return binascii.b2a_base64(compat26_str(self.bytes))
def tobytes(self):
return self.bytes
def topem(self):
return der.topem(self.bytes, "OPENSSH PRIVATE KEY")
def serialize_public(name, pub):
serial = _Serializer()
ktype = _get_key_type(name)
serial.put_str(ktype)
serial.put_str(pub)
return b" ".join([ktype, serial.encode()])
def serialize_private(name, pub, priv):
# encode public part
spub = _Serializer()
ktype = _get_key_type(name)
spub.put_str(ktype)
spub.put_str(pub)
# encode private part
spriv = _Serializer()
checksum = 0
spriv.put_u32(checksum)
spriv.put_u32(checksum)
spriv.put_raw(spub.tobytes())
spriv.put_str(priv + pub)
comment = b""
spriv.put_str(comment)
spriv.put_pad()
# top-level structure
main = _Serializer()
main.put_raw(_SK_MAGIC)
ciphername = kdfname = _NONE
main.put_str(ciphername)
main.put_str(kdfname)
nokdf = 0
main.put_u32(nokdf)
nkeys = 1
main.put_u32(nkeys)
main.put_str(spub.tobytes())
main.put_str(spriv.tobytes())
return main.topem()
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