def load(self):
keyfdir = "%s/sk/.%s" % (self.basedir, self.me)
if not os.path.exists(keyfdir):
os.mkdir(keyfdir)
return self
keyfname = '%s/%s' % (keyfdir, self.peer)
if not os.path.exists(keyfname):
return self
if not self.me_id:
self.me_id = publickey.Identity(self.me, basedir=self.basedir)
with open(keyfname, 'rb') as fd:
nonce = fd.read(nacl.crypto_box_NONCEBYTES)
plain = nacl.crypto_box_open(fd.read(), nonce, self.me_id.cp,
self.me_id.cs)
c = nacl.crypto_scalarmult_curve25519_BYTES
i = 0
self.e_in = plain[:c]
i += c
self.e_out = plain[i:i + c]
i += c
self.peer_pub = plain[i:i + c]
i += c
c = nacl.crypto_secretbox_KEYBYTES
self.out_k = plain[i:i + c]
i += c
self.in_k = plain[i:i + c]
i += c
self.in_prev = plain[i:i + c]
def test_crypto_box_open(self):
m = b"howdy"
pk, sk = pysodium.crypto_box_keypair()
n = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES)
c = pysodium.crypto_box(m, n, pk, sk)
plaintext = pysodium.crypto_box_open(c, n, pk, sk)
self.assertEqual(m, plaintext)
def load(self):
keyfdir="%s/sk/.%s" % (self.basedir, self.me)
if not os.path.exists(keyfdir):
os.mkdir(keyfdir)
return self
keyfname='%s/%s' % (keyfdir, self.peer)
if not os.path.exists(keyfname):
return self
if not self.me_id:
self.me_id = publickey.Identity(self.me, basedir=self.basedir)
with open(keyfname,'rb') as fd:
nonce = fd.read(nacl.crypto_box_NONCEBYTES)
plain = nacl.crypto_box_open(fd.read(), nonce, self.me_id.cp, self.me_id.cs)
c=nacl.crypto_scalarmult_curve25519_BYTES
i=0
self.e_in = plain[:c]
i+=c
self.e_out = plain[i:i+c]
i+=c
self.peer_pub = plain[i:i+c]
i+=c
c=nacl.crypto_secretbox_KEYBYTES
self.out_k = plain[i:i+c]
i+=c
self.in_k = plain[i:i+c]
i+=c
self.in_prev = plain[i:i+c]
def test_crypto_box_open(self):
m = b"howdy"
pk, sk = pysodium.crypto_box_keypair()
n = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES)
c = pysodium.crypto_box(m, n, pk, sk)
plaintext = pysodium.crypto_box_open(c, n, pk, sk)
self.assertEqual(m, plaintext)
def test_AsymCrypto_With_Seeded_Keypair(self):
msg = b"correct horse battery staple"
nonce = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES)
pk, sk = pysodium.crypto_box_seed_keypair("howdy")
c = pysodium.crypto_box(msg, nonce, pk, sk)
m = pysodium.crypto_box_open(c, nonce, pk, sk)
self.assertEqual(msg, m)
def keydecrypt(self, peers):
for nonce, ck in peers:
for keys in get_public_keys(basedir=self.basedir):
try:
key = nacl.crypto_box_open(ck, nonce, keys.cp, self.cs)
except ValueError:
continue
return (keys.name, key)
return None, None
def test_AsymCrypto_With_Seeded_Keypair(self):
msg = b"correct horse battery staple"
nonce = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES)
pk, sk = pysodium.crypto_box_seed_keypair("howdy")
c = pysodium.crypto_box(msg, nonce, pk, sk)
m = pysodium.crypto_box_open(c, nonce, pk, sk)
self.assertEqual(msg, m)
def keydecrypt(self, peers):
for nonce, ck in peers:
for keys in get_public_keys(basedir=self.basedir):
try:
key = nacl.crypto_box_open(ck, nonce, keys.cp, self.cs)
except ValueError:
continue
return (keys.name, key)
return None, None
def load(self):
keyfname="%s/dh/%s/%s" % (self.basedir, self.me, self.id)
if not self.me_id:
self.me_id = publickey.Identity(self.me, basedir=self.basedir)
with open(keyfname,'r') as fd:
nonce = fd.read(nacl.crypto_box_NONCEBYTES)
raw = fd.read()
self.key = nacl.crypto_box_open(raw, nonce, self.me_id.cp, self.me_id.cs)
os.remove(keyfname)
def locate_pack_recipient_key(recipients: Sequence[dict], my_verkey: bytes,
my_sigkey: bytes) -> (bytes, str, str):
"""
Locate pack recipient key.
Decode the encryption key and sender verification key from a
corresponding recipient block, if any is defined.
Args:
recipients: Recipients to locate
find_key: Function used to find private key
Returns:
A tuple of (cek, sender_vk, recip_vk_b58)
Raises:
ValueError: If no corresponding recipient key found
"""
not_found = []
for recip in recipients:
if not recip or "header" not in recip or "encrypted_key" not in recip:
raise ValueError("Invalid recipient header")
recip_vk_b58 = recip["header"].get("kid")
if bytes_to_b58(my_verkey) != recip_vk_b58:
not_found.append(recip_vk_b58)
continue
recip_vk = b58_to_bytes(recip_vk_b58)
pk = pysodium.crypto_sign_pk_to_box_pk(my_verkey)
sk = pysodium.crypto_sign_sk_to_box_sk(my_sigkey)
encrypted_key = b64_to_bytes(recip["encrypted_key"], urlsafe=True)
nonce_b64 = recip["header"].get("iv")
nonce = b64_to_bytes(nonce_b64, urlsafe=True) if nonce_b64 else None
sender_b64 = recip["header"].get("sender")
enc_sender = b64_to_bytes(sender_b64,
urlsafe=True) if sender_b64 else None
if nonce and enc_sender:
sender_vk_bin = pysodium.crypto_box_seal_open(enc_sender, pk, sk)
sender_vk = sender_vk_bin.decode("ascii")
sender_pk = pysodium.crypto_sign_pk_to_box_pk(
b58_to_bytes(sender_vk_bin))
cek = pysodium.crypto_box_open(encrypted_key, nonce, sender_pk, sk)
else:
sender_vk = None
cek = pysodium.crypto_box_seal_open(encrypted_key, pk, sk)
return cek, sender_vk, recip_vk_b58
raise ValueError(
"No corresponding recipient key found in {}".format(not_found))
def decrypt(self, cipher, nonce):
if self.in_k == (b'\0' * nacl.crypto_scalarmult_curve25519_BYTES):
# use pk crypto to decrypt the packet
return nacl.crypto_box_open(cipher, nonce, self.peer_id.cp, self.me_id.cs)
else:
# decrypt using chained keys
try:
return nacl.crypto_secretbox_open(cipher, nonce, self.in_k)
except ValueError:
# with previous key in case a prev send failed to be delivered
return nacl.crypto_secretbox_open(cipher, nonce, self.in_prev)
def handle(self):
data = self.request[0]
nonce = data[:pysodium.crypto_box_NONCEBYTES]
if nonce in nonces:
return
box = data[pysodium.crypto_box_NONCEBYTES:]
validity, payload = cbor.loads(
pysodium.crypto_box_open(box, nonce, ap, sk))
if validity < time():
return
nonces[nonce] = validity
cw.signal.emit(payload)
def decrypt(self, cipher, nonce):
if self.in_k == (b'\0' * nacl.crypto_scalarmult_curve25519_BYTES):
# use pk crypto to decrypt the packet
return nacl.crypto_box_open(cipher, nonce, self.peer_id.cp,
self.me_id.cs)
else:
# decrypt using chained keys
try:
return nacl.crypto_secretbox_open(cipher, nonce, self.in_k)
except ValueError:
# with previous key in case a prev send failed to be delivered
return nacl.crypto_secretbox_open(cipher, nonce, self.in_prev)
def decryptSalsaSession(self, proposeTuple, myEncrypKey):
cp = 0
nonce = proposeTuple['K'][cp:cp + 24]
cp += 24
cipherText = proposeTuple['K'][cp:]
# encrypSession = pysodium.crypto_box(cipherText, nonce, servPubkey, myEncrypKey)
try:
salsaSession = pysodium.crypto_box_open(cipherText, nonce,
proposeTuple['C']['K_E'],
myEncrypKey)
except:
salsaSession = None
return salsaSession
def test_box():
m = b"passwd"
pk, sk = pysodium.crypto_box_keypair()
n = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES)
print(n)
c = pysodium.crypto_box(m, n, pk, sk)
plaintext = pysodium.crypto_box_open(c, n, pk, sk)
print(plaintext)
def decrypt_body(self, msg, nonce_s, public_key, secret_key):
try:
body_s = pysodium.crypto_box_open(msg, nonce_s, public_key, secret_key)
if not body_s or (len(body_s) < 8):
return None
(seq_s, body_s) = self.next_chunk(body_s, 4)
(ack_s, body_s) = self.next_chunk(body_s, 4)
seq_n = self.bytes_int(seq_s)
ack_n = self.bytes_int(ack_s)
self.log_info('GOT seq ' + str(seq_n) + " ack " + str(ack_n))
self.log_info(repr(body_s))
return (seq_n, ack_n, body_s)
except ValueError:
return None
def decode_message(self, response: dict) -> (dict):
"""Decode response message.
Also verifies the received/expected nonce."""
try:
nonce = decode(response["nonce"])
msg_response = decode(response["message"])
msg_response = pysodium.crypto_box_open(
msg_response, nonce, self.server_key,
self.get_private_key()).decode()
msg_response = json.loads(msg_response)
logging.debug("Response message: " + str(msg_response))
verify_expected_nonce(self.nonce, nonce)
self.nonce = get_nonce(nonce)
except KeyError as e:
logging.warning("Invalid response: " + str(response))
msg_response = {}
return msg_response
def auth_decrypt_message(enc_message: bytes, my_verkey: bytes,
my_sigkey: bytes) -> (bytes, str):
"""
Apply auth_decrypt to a binary message.
Args:
enc_message: The encrypted message
secret: Secret for signing keys
Returns:
A tuple of (decrypted message, sender verkey)
"""
pk = pysodium.crypto_sign_pk_to_box_pk(my_verkey)
sk = pysodium.crypto_sign_sk_to_box_sk(my_sigkey)
body = pysodium.crypto_box_seal_open(enc_message, pk, sk)
unpacked = msgpack.unpackb(body, raw=False)
sender_vk = unpacked["sender"]
nonce = b64_to_bytes(unpacked["nonce"])
enc_message = b64_to_bytes(unpacked["msg"])
sender_pk = pysodium.crypto_sign_pk_to_box_pk(b58_to_bytes(sender_vk))
message = pysodium.crypto_box_open(enc_message, nonce, sender_pk, sk)
return message, sender_vk
def decrypt_handler(infile=None,
outfile=None,
self=None,
peer=None,
max_recipients=20,
basedir=None):
# provides a high level function to do decryption of files
# infile specifies the filename of the input file,
# if '-' or not specified it uses stdin
# outfile specifies the filename of the output file, if not specified
# it uses the same filename with '.pbp' appended
# self specifies the recipient of the message for using pk crypto
# basedir provides a root for the keystores needed for pk crypto
# if self is specified pk crypto is used, otherwise symmetric
# this function also handles buffering.
fd = inputfd(infile)
outfd = outputfd(outfile)
key = None
# asym
if self:
me = publickey.Identity(self, basedir=basedir)
if peer:
peer = publickey.Identity(peer, basedir=basedir, publicOnly=True)
sender = None
size = None
i = 0
while i < (max_recipients if not size else size):
i += 1
rnonce = fd.read(nacl.crypto_box_NONCEBYTES)
ct = fd.read(nacl.crypto_secretbox_KEYBYTES + 2 +
nacl.crypto_secretbox_MACBYTES)
if sender: continue
for keys in ([peer] if peer else publickey.get_public_keys(
basedir=basedir)):
try:
tmp = nacl.crypto_box_open(ct, rnonce, keys.cp, me.cs)
except ValueError:
continue
key = tmp[:nacl.crypto_secretbox_KEYBYTES]
size = struct.unpack('>H',
tmp[nacl.crypto_secretbox_KEYBYTES:])[0]
sender = keys.name
break
me.clear()
if not sender:
raise ValueError('decryption failed')
# sym
else:
pwd = getpass.getpass('Passphrase for decrypting: ')
key = scrypt.hash(pwd, scrypt_salt)[:nacl.crypto_secretbox_KEYBYTES]
sender = None
clearmem(pwd)
pwd = None
if key:
nonce = fd.read(nacl.crypto_secretbox_NONCEBYTES)
buf = fd.read(BLOCK_SIZE + nacl.crypto_secretbox_MACBYTES)
while buf:
outfd.write(decrypt((nonce, buf), k=key))
nonce = inc_nonce(nonce)
buf = fd.read(BLOCK_SIZE + nacl.crypto_secretbox_MACBYTES)
clearmem(key)
key = None
if fd != sys.stdin: fd.close()
if outfd != sys.stdout and type(outfd) == file: outfd.close()
return sender
def test_crypto_box_open(self):
pk, sk = pysodium.crypto_box_keypair()
n = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES)
c = pysodium.crypto_box(b"howdy", n, pk, sk)
pysodium.crypto_box_open(c, n, pk, sk)
def DecryptPacket(packet, pk, sk):
nounce = packet[:24]
data = packet[24:]
LAST_NOUNCE = nounce
return pysodium.crypto_box_open(data, nounce, pk, sk)
def decrypt(message, nonce, serverKey, secretKey):
return pysodium.crypto_box_open(message, nonce, serverKey, secretKey)
def decrypt_handler(infile=None, outfile=None, self=None, peer=None, max_recipients = 20, basedir=None):
# provides a high level function to do decryption of files
# infile specifies the filename of the input file,
# if '-' or not specified it uses stdin
# outfile specifies the filename of the output file, if not specified
# it uses the same filename with '.pbp' appended
# self specifies the recipient of the message for using pk crypto
# basedir provides a root for the keystores needed for pk crypto
# if self is specified pk crypto is used, otherwise symmetric
# this function also handles buffering.
fd = inputfd(infile)
outfd = outputfd(outfile)
key = None
# asym
if self:
me = publickey.Identity(self, basedir=basedir)
if peer:
peer = publickey.Identity(peer, basedir=basedir, publicOnly=True)
sender = None
size = None
i=0
while i < (max_recipients if not size else size):
i+=1
rnonce = fd.read(nacl.crypto_box_NONCEBYTES)
ct = fd.read(nacl.crypto_secretbox_KEYBYTES+2+nacl.crypto_secretbox_MACBYTES)
if sender: continue
for keys in ([peer] if peer else publickey.get_public_keys(basedir=basedir)):
try:
tmp = nacl.crypto_box_open(ct, rnonce, keys.cp, me.cs)
except ValueError:
continue
key = tmp[:nacl.crypto_secretbox_KEYBYTES]
size = struct.unpack('>H',tmp[nacl.crypto_secretbox_KEYBYTES:])[0]
sender = keys.name
break
me.clear()
if not sender:
raise ValueError('decryption failed')
# sym
else:
pwd = getpass.getpass('Passphrase for decrypting: ')
key = scrypt.hash(pwd, scrypt_salt)[:nacl.crypto_secretbox_KEYBYTES]
sender = None
clearmem(pwd)
pwd=None
if key:
nonce = fd.read(nacl.crypto_secretbox_NONCEBYTES)
buf = fd.read(BLOCK_SIZE + nacl.crypto_secretbox_MACBYTES)
while buf:
outfd.write(decrypt((nonce, buf), k = key))
nonce = inc_nonce(nonce)
buf = fd.read(BLOCK_SIZE + nacl.crypto_secretbox_MACBYTES)
clearmem(key)
key = None
if fd != sys.stdin: fd.close()
if outfd != sys.stdout: outfd.close()
return sender
def decrypt_message(public_key, secret_key, message): decrypted = pysodium.crypto_box_open(message[40:], message[0:24], public_key, secret_key) return decrypted
def decrypt(ecryptedMessage, nonce, private_key, pub_key):
new_private_key = pysodium.crypto_sign_sk_to_box_sk(private_key)
new_pub_key = pysodium.crypto_sign_pk_to_box_pk(pub_key)
return pysodium.crypto_box_open(b64decode(ecryptedMessage),
b64decode(nonce), new_pub_key,
new_private_key).decode("utf-8")
def test_pysodium():
"""
Test all the functions needed from pysodium libarary (libsodium)
"""
# crypto_sign signatures with Ed25519 keys
# create keypair without seed
verkey, sigkey = pysodium.crypto_sign_keypair()
assert len(verkey) == 32 == pysodium.crypto_sign_PUBLICKEYBYTES
assert len(sigkey) == 64 == pysodium.crypto_sign_SECRETKEYBYTES
assert 32 == pysodium.crypto_sign_SEEDBYTES
sigseed = pysodium.randombytes(pysodium.crypto_sign_SEEDBYTES)
assert len(sigseed) == 32
# seed = (b'J\xeb\x06\xf2BA\xd6/T\xe1\xe2\xe2\x838\x8a\x99L\xd9\xb5(\\I\xccRb\xc8\xd5\xc7Y\x1b\xb6\xf0')
# Ann's seed
sigseed = (
b'PTi\x15\xd5\xd3`\xf1u\x15}^r\x9bfH\x02l\xc6\x1b\x1d\x1c\x0b9\xd7{\xc0_\xf2K\x93`'
)
assert len(sigseed) == 32
# try key stretching from 16 bytes using pysodium.crypto_pwhash()
assert 16 == pysodium.crypto_pwhash_SALTBYTES
salt = pysodium.randombytes(pysodium.crypto_pwhash_SALTBYTES)
assert len(salt) == 16
# salt = b'\x19?\xfa\xc7\x8f\x8b\x7f\x8b\xdbS"$\xd7[\x85\x87'
# algorithm default is argon2id
sigseed = pysodium.crypto_pwhash(
outlen=32,
passwd="",
salt=salt,
opslimit=pysodium.crypto_pwhash_OPSLIMIT_INTERACTIVE,
memlimit=pysodium.crypto_pwhash_MEMLIMIT_INTERACTIVE,
alg=pysodium.crypto_pwhash_ALG_DEFAULT)
assert len(sigseed) == 32
# seed = (b'\xa9p\x89\x7f+\x0e\xc4\x9c\xf2\x01r\xafTI\xc0\xfa\xac\xd5\x99\xf8O\x8f=\x843\xa2\xb6e\x9fO\xff\xd0')
# creates signing/verification key pair from seed
verkey, sigkey = pysodium.crypto_sign_seed_keypair(sigseed)
assert len(verkey) == 32
assert len(sigkey) == 64
# sigkey is seed and verkey concatenated. Libsodium does this as an optimization
# because the signing scheme needs both the private key (seed) and the public key so
# instead of recomputing the public key each time from the secret key it requires
# the public key as an input of and instead of two separate inputs, one for the
# secret key and one for the public key, it uses a concatenated form.
# Essentially crypto_sign_seed_keypair and crypto_sign_keypair return redundant
# information in the duple (verkey, sigkey) because sigkey includes verkey
# so one could just store sigkey and extract verkey or sigseed when needed
# or one could just store verkey and sigseed and reconstruct sigkey when needed.
# crypto_sign_detached requires sigkey (sigseed + verkey)
# crypto_sign_verify_detached reqires verkey only
# https://crypto.stackexchange.com/questions/54353/why-are-nacl-secret-keys-64-bytes-for-signing-but-32-bytes-for-box
assert sigseed == sigkey[:32]
assert verkey == sigkey[32:]
assert sigkey == sigseed + verkey
# vk = (b'B\xdd\xbb}8V\xa0\xd6lk\xcf\x15\xad9\x1e\xa7\xa1\xfe\xe0p<\xb6\xbex\xb0s\x8d\xd6\xf5\xa5\xe8Q')
# utility function to extract seed from secret sigkey (really just extracting from front half)
assert sigseed == pysodium.crypto_sign_sk_to_seed(sigkey)
assert 64 == pysodium.crypto_sign_BYTES
msg = "The lazy dog jumped over the river"
msgb = msg.encode(
"utf-8") # must convert unicode string to bytes in order to sign it
assert msgb == b'The lazy dog jumped over the river'
sig = pysodium.crypto_sign_detached(msgb, sigseed +
verkey) # sigkey = seed + verkey
assert len(sig) == 64
"""
sig = (b"\x99\xd2<9$$0\x9fk\xfb\x18\xa0\x8c@r\x122.k\xb2\xc7\x1fp\x0e'm\x8f@"
b'\xaa\xa5\x8c\xc8n\x85\xc8!\xf6q\x91p\xa9\xec\xcf\x92\xaf)\xde\xca'
b'\xfc\x7f~\xd7o|\x17\x82\x1d\xd4<o"\x81&\t')
"""
#siga = pysodium.crypto_sign(msg.encode("utf-8"), sk)[:pysodium.crypto_sign_BYTES]
#assert len(siga) == 64
#assert sig == siga
try: # verify returns None if valid else raises ValueError
result = pysodium.crypto_sign_verify_detached(sig, msgb, verkey)
except Exception as ex:
assert False
assert not result
assert result is None
sigbad = sig[:-1]
sigbad += b'A'
try: # verify returns None if valid else raises ValueError
result = pysodium.crypto_sign_verify_detached(sigbad, msgb, verkey)
except Exception as ex:
assert True
assert isinstance(ex, ValueError)
# crypto_box authentication encryption with X25519 keys
apubkey, aprikey = pysodium.crypto_box_keypair()
assert len(apubkey) == 32 == pysodium.crypto_box_SECRETKEYBYTES
assert len(aprikey) == 32 == pysodium.crypto_box_PUBLICKEYBYTES
repubkey = pysodium.crypto_scalarmult_curve25519_base(aprikey)
assert repubkey == apubkey
assert 32 == pysodium.crypto_box_SEEDBYTES
boxseed = pysodium.randombytes(pysodium.crypto_box_SEEDBYTES)
assert len(boxseed) == 32
bpubkey, bprikey = pysodium.crypto_box_seed_keypair(boxseed)
assert len(bpubkey) == 32
assert len(bprikey) == 32
repubkey = pysodium.crypto_scalarmult_curve25519_base(bprikey)
assert repubkey == bpubkey
assert 24 == pysodium.crypto_box_NONCEBYTES
nonce = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES)
assert len(nonce) == 24
# nonce = b'\x11\xfbi<\xf2\xb6k\xa05\x0c\xf9\x86t\x07\x8e\xab\x8a\x97nG\xe8\x87,\x94'
atob_tx = "Hi Bob I'm Alice"
atob_txb = atob_tx.encode("utf-8")
# Detached recomputes shared key every time.
# A encrypt to B
acrypt, amac = pysodium.crypto_box_detached(atob_txb, nonce, bpubkey,
aprikey)
amacl = pysodium.crypto_box_MACBYTES
assert amacl == 16
# amac = b'\xa1]\xc6ML\xe2\xa9:\xc0\xdc\xab\xa5\xc4\xc7\xf4\xdb'
# acrypt = (b'D\n\x17\xb6z\xd8+t)\xcc`y\x1d\x10\x0cTC\x02\xb5@\xe2\xf2\xc9-(\xec*O\xb8~\xe2\x1a\xebO')
# when transmitting prepend amac to crypt
acipher = pysodium.crypto_box(atob_txb, nonce, bpubkey, aprikey)
assert acipher == amac + acrypt
atob_rxb = pysodium.crypto_box_open_detached(acrypt, amac, nonce, apubkey,
bprikey)
atob_rx = atob_rxb.decode("utf-8")
assert atob_rx == atob_tx
assert atob_rxb == atob_txb
atob_rxb = pysodium.crypto_box_open(acipher, nonce, apubkey, bprikey)
atob_rx = atob_rxb.decode("utf-8")
assert atob_rx == atob_tx
assert atob_rxb == atob_txb
btoa_tx = "Hello Alice I am Bob"
btoa_txb = btoa_tx.encode("utf-8")
# B encrypt to A
bcrypt, bmac = pysodium.crypto_box_detached(btoa_txb, nonce, apubkey,
bprikey)
# bmac = b'\x90\xe07=\xd22\x8fh2\xff\xdd\x84tC\x053'
# bcrypt = (b'8\xb5\xba\xe7\xcc\xae B\xefx\xe6{U\xf7\xefA\x00\xc7|\xdbu\xcfc\x01$\xa9\xa2P\xa7\x84\xa5\xae\x180')
# when transmitting prepend amac to crypt
bcipher = pysodium.crypto_box(btoa_txb, nonce, apubkey, bprikey)
assert bcipher == bmac + bcrypt
btoa_rxb = pysodium.crypto_box_open_detached(bcrypt, bmac, nonce, bpubkey,
aprikey)
btoa_rx = btoa_rxb.decode("utf-8")
assert btoa_rx == btoa_tx
assert btoa_rxb == btoa_txb
btoa_rxb = pysodium.crypto_box_open(bcipher, nonce, bpubkey, aprikey)
btoa_rx = btoa_rxb.decode("utf-8")
assert btoa_rx == btoa_tx
assert btoa_rxb == btoa_txb
# compute shared key
asymkey = pysodium.crypto_box_beforenm(bpubkey, aprikey)
bsymkey = pysodium.crypto_box_beforenm(apubkey, bprikey)
assert asymkey == bsymkey
acipher = pysodium.crypto_box_afternm(atob_txb, nonce, asymkey)
atob_rxb = pysodium.crypto_box_open_afternm(acipher, nonce, bsymkey)
assert atob_rxb == atob_txb
bcipher = pysodium.crypto_box_afternm(btoa_txb, nonce, bsymkey)
btoa_rxb = pysodium.crypto_box_open_afternm(bcipher, nonce, asymkey)
assert btoa_rxb == btoa_txb
# crypto_box_seal public key encryption with X25519 keys
# uses same X25519 type of keys as crypto_box authenticated encryption
# so when converting sign key Ed25519 to X25519 can use for both types of encryption
pubkey, prikey = pysodium.crypto_box_keypair()
assert len(pubkey) == 32 == pysodium.crypto_box_PUBLICKEYBYTES
assert len(prikey) == 32 == pysodium.crypto_box_SECRETKEYBYTES
assert 48 == pysodium.crypto_box_SEALBYTES
msg_txb = "Catch me if you can.".encode("utf-8")
assert msg_txb == b'Catch me if you can.'
cipher = pysodium.crypto_box_seal(msg_txb, pubkey)
assert len(cipher) == 48 + len(msg_txb)
msg_rxb = pysodium.crypto_box_seal_open(cipher, pubkey, prikey)
assert msg_rxb == msg_txb
# convert Ed25519 key pair to X25519 key pair
# https://blog.filippo.io/using-ed25519-keys-for-encryption/
# https://libsodium.gitbook.io/doc/advanced/ed25519-curve25519
# crypto_sign_ed25519_pk_to_curve25519
# crypto_sign_ed25519_sk_to_curve25519
pubkey = pysodium.crypto_sign_pk_to_box_pk(verkey)
assert len(pubkey) == pysodium.crypto_box_PUBLICKEYBYTES
prikey = pysodium.crypto_sign_sk_to_box_sk(sigkey)
assert len(prikey) == pysodium.crypto_box_SECRETKEYBYTES
repubkey = pysodium.crypto_scalarmult_curve25519_base(prikey)
assert repubkey == pubkey
msg_txb = "Encoded using X25519 key converted from Ed25519 key".encode(
"utf-8")
cipher = pysodium.crypto_box_seal(msg_txb, pubkey)
assert len(cipher) == 48 + len(msg_txb)
msg_rxb = pysodium.crypto_box_seal_open(cipher, pubkey, prikey)
assert msg_rxb == msg_txb
"""
def decrypt_message(public_key, secret_key, message):
decrypted = pysodium.crypto_box_open(message[40:], message[0:24],
public_key, secret_key)
return decrypted
def __decrypt(msg, nonce, serverKey, secretKey):
dec = pysodium.crypto_box_open(base64.b64decode(msg),
base64.b64decode(nonce),
base64.b64decode(serverKey),
base64.b64decode(secretKey))
return dec
def test_crypto_box_open(self):
pk, sk = pysodium.crypto_box_keypair()
n = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES)
c = pysodium.crypto_box(b"howdy", n, pk, sk)
pysodium.crypto_box_open(c, n, pk, sk)
def oneshotDecrypt(sk, pk, data):
n = data[:pysodium.crypto_box_NONCEBYTES]
c = data[len(n):]
return pysodium.crypto_box_open(c, n, pk, sk)
