def crypto_generichash(message, key, out_len=crypto_generichash_BYTES):
#if out_len < crypto_generichash_BYTES_MIN:
#raise CryptoError("out_len length shorter than crypto_generichash_BYTES_MIN")
if out_len > crypto_generichash_BYTES_MAX:
raise CryptoError("out_len length longer than crypto_generichash_BYTES_MAX")
if not isinstance(message, (str)):
raise CryptoError("message must be str")
message_len = len(message)
if not key:
key = lib.ffi.NULL
key_len = 0
else:
key_len = len(key)
if key_len < crypto_generichash_KEYBYTES_MIN:
raise CryptoError("key length shorter than crypto_generichash_keybytes_min")
if key_len > crypto_generichash_KEYBYTES_MAX:
raise CryptoError("key length longer than crypto_generichash_keybytes_max")
out = lib.ffi.new("unsigned char[]", out_len)
if lib.crypto_generichash(out, out_len, message, message_len, key, key_len) != 0:
raise CryptoError("An error occurred while crypto_generichash")
return lib.ffi.buffer(out, out_len)[:]
def sodium_init():
"""
Initializes sodium, picking the best implementations available for this
machine.
"""
if lib.sodium_init() != 0:
raise CryptoError("Could not initialize sodium")
def crypto_secretbox_open(key, ciphertext, nonce):
"""
Decrypt and returns the encrypted message ``ciphertext`` with the secret
``key`` and the nonce ``nonce``.
:param key: bytes
:param ciphertext: bytes
:param nonce: bytes
:rtype: bytes
"""
if len(key) != crypto_secretbox_KEYBYTES:
raise ValueError("Invalid key")
if len(nonce) != crypto_secretbox_NONCEBYTES:
raise ValueError("Invalid nonce")
padded = b"\x00" * crypto_secretbox_BOXZEROBYTES + ciphertext
plaintext = lib.ffi.new("unsigned char[]", len(padded))
if lib.crypto_secretbox_open(plaintext, padded, len(padded), nonce,
key) != 0:
raise CryptoError("Decryption failed. Ciphertext failed verification")
plaintext = lib.ffi.buffer(plaintext, len(padded))
return plaintext[crypto_secretbox_ZEROBYTES:]
def crypto_box_open(ciphertext, nonce, pk, sk):
"""
Decrypts and returns an encrypted message ``ciphertext``, using the secret
key ``sk``, public key ``pk``, and the nonce ``nonce``.
:param ciphertext: bytes
:param nonce: bytes
:param pk: bytes
:param sk: bytes
:rtype: bytes
"""
if len(nonce) != crypto_box_NONCEBYTES:
raise ValueError("Invalid nonce size")
if len(pk) != crypto_box_PUBLICKEYBYTES:
raise ValueError("Invalid public key")
if len(sk) != crypto_box_SECRETKEYBYTES:
raise ValueError("Invalid secret key")
padded = (b"\x00" * crypto_box_BOXZEROBYTES) + ciphertext
plaintext = ffi.new("unsigned char[]", len(padded))
if lib.crypto_box_open(plaintext, padded, len(padded), nonce, pk, sk) != 0:
raise CryptoError("An error occurred trying to decrypt the message")
return ffi.buffer(plaintext, len(padded))[crypto_box_ZEROBYTES:]
def _get_skpk_from_decrypted_private_blob(blob):
checkint1 = blob.read(4)
checkint2 = blob.read(4)
if checkint1 != checkint2:
LOG.error('Check: %s != %s', checkint1, checkint2)
raise CryptoError()
# We should parse n keys, but n is 1
decode_string(blob) # ignore key name
decode_string(blob) # ignore pubkey
skpk = decode_string(blob)
LOG.debug('Private Key blob: %s', skpk.hex().upper())
assert len(skpk) == 64
sk = skpk[:32] # first half = priv key
LOG.debug('ed25519 sk: %s', sk.hex().upper())
pk = skpk[32:] # second half = pub key
LOG.debug('ed25519 pk: %s', pk.hex().upper())
seckey = crypto_sign_ed25519_sk_to_curve25519(skpk)
LOG.debug('x25519 sk: %s', seckey.hex().upper())
pubkey = crypto_sign_ed25519_pk_to_curve25519(pk)
LOG.debug('x25519 pk: %s', pubkey.hex().upper())
return (seckey, pubkey)
def crypto_hash_sha512(message):
"""
Hashes and returns the message ``message``.
:param message: bytes
:rtype: bytes
"""
digest = lib.ffi.new("unsigned char[]", crypto_hash_sha512_BYTES)
if lib.crypto_hash_sha512(digest, message, len(message)) != 0:
raise CryptoError("Hashing failed")
return lib.ffi.buffer(digest, crypto_hash_sha512_BYTES)[:]
def crypto_shorthash(in_, k):
if not in_:
in_ = lib.ffi.new("unsigned char []", 1)
in_len = 0
else:
in_len = len(in_)
out = lib.ffi.new("unsigned char []", crypto_shorthash_BYTES)
if lib.crypto_shorthash(out, in_, in_len, k) != 0:
raise CryptoError("An error occurred while crypto_shorthash")
return lib.ffi.buffer(out, crypto_shorthash_BYTES)[:]
def crypto_scalarmult_base(n):
"""
Computes and returns the scalar product of a standard group element and an
integer ``n``.
:param n: bytes
:rtype: bytes
"""
q = lib.ffi.new("unsigned char[]", crypto_scalarmult_BYTES)
if lib.crypto_scalarmult_base(q, n) != 0:
raise CryptoError(
"An error occurred while computing the scalar product")
return lib.ffi.buffer(q, crypto_scalarmult_SCALARBYTES)[:]
def crypto_sign(message, sk):
"""
Signs the message ``message`` using the secret key ``sk`` and returns the
signed message.
:param message: bytes
:param sk: bytes
:rtype: bytes
"""
signed = lib.ffi.new("unsigned char[]", len(message) + crypto_sign_BYTES)
signed_len = lib.ffi.new("unsigned long long *")
if lib.crypto_sign(signed, signed_len, message, len(message), sk) != 0:
raise CryptoError("Failed to sign the message")
return lib.ffi.buffer(signed, signed_len[0])[:]
def crypto_sign_keypair():
"""
Returns a randomly generated public key and secret key.
:rtype: (bytes(public_key), bytes(secret_key))
"""
pk = lib.ffi.new("unsigned char[]", crypto_sign_PUBLICKEYBYTES)
sk = lib.ffi.new("unsigned char[]", crypto_sign_SECRETKEYBYTES)
if lib.crypto_sign_keypair(pk, sk) != 0:
raise CryptoError("An error occurred while generating keypairs")
return (
lib.ffi.buffer(pk, crypto_sign_PUBLICKEYBYTES)[:],
lib.ffi.buffer(sk, crypto_sign_SECRETKEYBYTES)[:],
)
def crypto_sign_seed_keypair(seed):
"""
Computes and returns the public key and secret key using the seed ``seed``.
:param seed: bytes
:rtype: (bytes(public_key), bytes(secret_key))
"""
if len(seed) != crypto_sign_SEEDBYTES:
raise ValueError("Invalid seed")
pk = lib.ffi.new("unsigned char[]", crypto_sign_PUBLICKEYBYTES)
sk = lib.ffi.new("unsigned char[]", crypto_sign_SECRETKEYBYTES)
if lib.crypto_sign_seed_keypair(pk, sk, seed) != 0:
raise CryptoError("An error occurred while generating keypairs")
return (
lib.ffi.buffer(pk, crypto_sign_PUBLICKEYBYTES)[:],
lib.ffi.buffer(sk, crypto_sign_SECRETKEYBYTES)[:],
)
def crypto_box_beforenm(pk, sk):
"""
Computes and returns the shared key for the public key ``pk`` and the
secret key ``sk``. This can be used to speed up operations where the same
set of keys is going to be used multiple times.
:param pk: bytes
:param sk: bytes
:rtype: bytes
"""
if len(pk) != crypto_box_PUBLICKEYBYTES:
raise ValueError("Invalid public key")
if len(sk) != crypto_box_SECRETKEYBYTES:
raise ValueError("Invalid secret key")
k = lib.ffi.new("unsigned char[]", crypto_box_BEFORENMBYTES)
if lib.crypto_box_beforenm(k, pk, sk) != 0:
raise CryptoError("An error occurred computing the shared key.")
return lib.ffi.buffer(k, crypto_box_BEFORENMBYTES)[:]
def crypto_box_afternm(message, nonce, k):
"""
Encrypts and returns the message ``message`` using the shared key ``k`` and
the nonce ``nonce``.
:param message: bytes
:param nonce: bytes
:param k: bytes
:rtype: bytes
"""
if len(nonce) != crypto_box_NONCEBYTES:
raise ValueError("Invalid nonce")
if len(k) != crypto_box_BEFORENMBYTES:
raise ValueError("Invalid shared key")
padded = b"\x00" * crypto_box_ZEROBYTES + message
ciphertext = lib.ffi.new("unsigned char[]", len(padded))
if lib.crypto_box_afternm(ciphertext, padded, len(padded), nonce, k) != 0:
raise CryptoError("An error occurred trying to encrypt the message")
return lib.ffi.buffer(ciphertext, len(padded))[crypto_box_BOXZEROBYTES:]
def crypto_secretbox(key, message, nonce):
"""
Encrypts and returns the message ``message`` with the secret ``key`` and
the nonce ``nonce``.
:param key: bytes
:param message: bytes
:param nonce: bytes
:rtype: bytes
"""
if len(key) != crypto_secretbox_KEYBYTES:
raise ValueError("Invalid key")
if len(nonce) != crypto_secretbox_NONCEBYTES:
raise ValueError("Invalid nonce")
padded = b"\x00" * crypto_secretbox_ZEROBYTES + message
ciphertext = lib.ffi.new("unsigned char[]", len(padded))
if lib.crypto_secretbox(ciphertext, padded, len(padded), nonce, key) != 0:
raise CryptoError("Encryption failed")
ciphertext = lib.ffi.buffer(ciphertext, len(padded))
return ciphertext[crypto_secretbox_BOXZEROBYTES:]
def crypto_box_open_afternm(ciphertext, nonce, k):
"""
Decrypts and returns the encrypted message ``ciphertext``, using the shared
key ``k`` and the nonce ``nonce``.
:param ciphertext: bytes
:param nonce: bytes
:param k: bytes
:rtype: bytes
"""
if len(nonce) != crypto_box_NONCEBYTES:
raise ValueError("Invalid nonce")
if len(k) != crypto_box_BEFORENMBYTES:
raise ValueError("Invalid shared key")
padded = (b"\x00" * crypto_box_BOXZEROBYTES) + ciphertext
plaintext = ffi.new("unsigned char[]", len(padded))
if lib.crypto_box_open_afternm(
plaintext, padded, len(padded), nonce, k) != 0:
raise CryptoError("An error occurred trying to decrypt the message")
return ffi.buffer(plaintext, len(padded))[crypto_box_ZEROBYTES:]
def parse_private_key(stream, callback):
ciphername = decode_string(stream)
kdfname = decode_string(stream)
kdfoptions = decode_string(stream)
LOG.info("Ciphername: %s", ciphername)
LOG.info("KDF: %s", kdfname)
# LOG.debug("KDF options %s", kdfoptions)
if kdfname not in (b"none", b"bcrypt"):
raise ValueError("Invalid SSH Key format")
if kdfname != b"none" and ciphername == b"none":
raise ValueError("Invalid SSH Key format")
if kdfname != b'none':
# assert (kdfname == b"bcrypt")
assert kdfoptions
kdfoptions = io.BytesIO(kdfoptions)
salt = decode_string(kdfoptions)
rounds = int.from_bytes(kdfoptions.read(4), byteorder='big')
LOG.info("Salt: %s", salt.hex())
LOG.info("Rounds: %d", rounds)
assert not kdfoptions.read(), "There should be no trailing data in the kdfoptions buffer"
else:
LOG.debug("Not Encrypted")
assert( not kdfoptions )
n = int.from_bytes(stream.read(4), byteorder='big') # u32
LOG.debug("Number of keys: %d", n)
assert( n == 1 ) # Apparently always 1: https://github.com/openssh/openssh-portable/blob/master/sshkey.c#L3857
decode_string(stream) # ignore the public keys
private_ciphertext = decode_string(stream) # padded list of private keys
assert not stream.read(), "There should be no trailing data"
if ciphername == b'none':
# LOG.debug('Non-Encrypted private data: %s', private_data)
private_data = io.BytesIO(private_ciphertext) # no need to unpad
return _get_skpk_from_private_blob(private_data) # ignore the comment
# Encrypted content
# LOG.debug('------ Encrypted private data (%d): %s', len(private_ciphertext), private_ciphertext)
assert( callback and callable(callback) )
passphrase = callback().encode()
# LOG.debug('Passphrase: %s', passphrase)
if not passphrase and ciphername != b"none":
raise ValueError("Passphrase required")
dklen = get_derived_key_length(ciphername) # key length + IV length
LOG.debug('Derived Key len: %d', dklen)
derived_key = derive_key(kdfname, passphrase, salt, rounds, dklen=dklen)
LOG.debug('Derived Key: %s', derived_key)
decryptor = get_cipher(ciphername, derived_key).decryptor()
assert( len(private_ciphertext) % _block_size(ciphername) == 0 ), "Invalid cipher block length"
private_data = decryptor.update(private_ciphertext) + decryptor.finalize()
# LOG.debug('------- Private data (%d): %s', len(private_data), private_data)
if private_data[:4] != private_data[4:8]: # check don't pass
LOG.debug('Check: %s != %s', private_data[:4], private_data[4:8])
raise CryptoError()
private_data = io.BytesIO(private_data[8:])
# Note: we ignore the comment and padding after the priv blob
return _get_skpk_from_private_blob(private_data) # no need to unpad
