def auth_crypt_message(message: bytes, to_verkey: bytes, from_verkey: bytes, from_sigkey: bytes) -> bytes: """ Apply auth_crypt to a binary message. Args: message: The message to encrypt to_verkey: To recipient's verkey from_verkey: Sender verkey, included in combo box for verification from_sigkey: Sender sigkey, included to authenticated encrypt the message Returns: The encrypted message """ nonce = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES) target_pk = pysodium.crypto_sign_pk_to_box_pk(to_verkey) sk = pysodium.crypto_sign_sk_to_box_sk(from_sigkey) enc_body = pysodium.crypto_box(message, nonce, target_pk, sk) combo_box = OrderedDict([ ("msg", bytes_to_b64(enc_body)), ("sender", bytes_to_b58(from_verkey)), ("nonce", bytes_to_b64(nonce)), ]) combo_box_bin = msgpack.packb(combo_box, use_bin_type=True) enc_message = pysodium.crypto_box_seal(combo_box_bin, target_pk) return enc_message
def auth_crypt_message(message: bytes, to_verkey: bytes, from_secret: bytes) -> bytes: """ Apply auth_crypt to a binary message. Args: message: The message to encrypt to_verkey: To recipient's verkey from_secret: The seed to use Returns: The encrypted message """ nonce = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES) target_pk = pysodium.crypto_sign_pk_to_box_pk(to_verkey) sender_pk, sender_sk = create_keypair(from_secret) sk = pysodium.crypto_sign_sk_to_box_sk(sender_sk) enc_body = pysodium.crypto_box(message, nonce, target_pk, sk) combo_box = OrderedDict( [ ("msg", bytes_to_b64(enc_body)), ("sender", bytes_to_b58(sender_pk)), ("nonce", bytes_to_b64(nonce)), ] ) combo_box_bin = msgpack.packb(combo_box, use_bin_type=True) enc_message = pysodium.crypto_box_seal(combo_box_bin, target_pk) return enc_message
def getkey(keydir): datadir = os.path.expanduser(keydir) esk = None try: with open(datadir + 'server-key', 'rb') as fd: esk = fd.read(pysodium.crypto_sign_SECRETKEYBYTES) with open(datadir + 'server-xkey', 'rb') as fd: xsk = fd.read(pysodium.crypto_box_SECRETKEYBYTES) with open(datadir + 'server-xkey.pub', 'rb') as fd: xpk = fd.read(pysodium.crypto_box_PUBLICKEYBYTES) return esk, xsk, xpk except FileNotFoundError: print("no server key found, generating...") if not os.path.exists(datadir): os.mkdir(datadir, 0o700) if esk is None: epk, esk = pysodium.crypto_sign_keypair() else: epk = pysodium.crypto_sign_sk_to_pk(esk) xsk = pysodium.crypto_sign_sk_to_box_sk(esk) xpk = pysodium.crypto_sign_pk_to_box_pk(epk) with open(datadir + 'server-key', 'wb') as fd: os.fchmod(fd.fileno(), 0o600) fd.write(esk) with open(datadir + 'server-key.pub', 'wb') as fd: fd.write(epk) with open(datadir + 'server-xkey', 'wb') as fd: os.fchmod(fd.fileno(), 0o600) fd.write(xsk) with open(datadir + 'server-xkey.pub', 'wb') as fd: fd.write(xpk) print("please share `%s` with all clients" % (datadir + 'server-key.pub')) return esk, xsk, xpk
def prepare_pack_recipient_keys(to_verkeys: Sequence[bytes], from_secret: bytes = None) -> (str, bytes): """ Assemble the recipients block of a packed message. Args: to_verkeys: Verkeys of recipients from_secret: Secret to use for signing keys Returns: A tuple of (json result, key) """ cek = pysodium.crypto_secretstream_xchacha20poly1305_keygen() recips = [] for target_vk in to_verkeys: target_pk = pysodium.crypto_sign_pk_to_box_pk(target_vk) if from_secret: sender_pk, sender_sk = create_keypair(from_secret) sender_vk = bytes_to_b58(sender_pk).encode("ascii") enc_sender = pysodium.crypto_box_seal(sender_vk, target_pk) sk = pysodium.crypto_sign_sk_to_box_sk(sender_sk) nonce = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES) enc_cek = pysodium.crypto_box(cek, nonce, target_pk, sk) else: enc_sender = None nonce = None enc_cek = pysodium.crypto_box_seal(cek, target_pk) recips.append( OrderedDict([ ("encrypted_key", bytes_to_b64(enc_cek, urlsafe=True)), ( "header", OrderedDict([ ("kid", bytes_to_b58(target_vk)), ( "sender", bytes_to_b64(enc_sender, urlsafe=True) if enc_sender else None, ), ( "iv", bytes_to_b64(nonce, urlsafe=True) if nonce else None, ), ]), ), ])) data = OrderedDict([ ("enc", "xchacha20poly1305_ietf"), ("typ", "JWM/1.0"), ("alg", "Authcrypt" if from_secret else "Anoncrypt"), ("recipients", recips), ]) return json.dumps(data), cek
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 anon_decrypt_message(enc_message: bytes, secret: bytes) -> bytes: """ Apply anon_decrypt to a binary message. Args: enc_message: The encrypted message secret: The seed to use Returns: The decrypted message """ sign_pk, sign_sk = create_keypair(secret) pk = pysodium.crypto_sign_pk_to_box_pk(sign_pk) sk = pysodium.crypto_sign_sk_to_box_sk(sign_sk) message = pysodium.crypto_box_seal_open(enc_message, pk, sk) return message
def data_received(self, data): if verbose: print('Data received: ', data, file=sys.stderr) try: data = pysodium.crypto_sign_open(data, self.handler.getserverkey()) except ValueError: raise ValueError('invalid signature.\nabort') if data != b'ok' and (data[:-42] == b'fail' or len(data) != sphinxlib.DECAF_255_SER_BYTES + 90): raise ValueError('fail') if not self.b: self.cb() return rwd = sphinxlib.finish(self.pwd, self.b, data[:sphinxlib.DECAF_255_SER_BYTES]) if self.handler.namesite is not None: if self.handler.namesite['name'].encode() not in self.handler.list( self.handler.namesite['site']): self.handler.cacheuser(self.handler.namesite) rule = data[sphinxlib.DECAF_255_SER_BYTES:] esk = self.handler.getkey() sk = pysodium.crypto_sign_sk_to_box_sk(esk) epk = pysodium.crypto_sign_sk_to_pk(esk) pk = pysodium.crypto_sign_pk_to_box_pk(epk) rule = pysodium.crypto_box_seal_open(rule, pk, sk) if len(rule) != 42: raise ValueError('fail') rk = pysodium.crypto_generichash(self.handler.getkey(), self.handler.getsalt()) rule = pysodium.crypto_secretbox_open(rule[24:], rule[:24], rk) rule = struct.unpack(">H", rule)[0] size = (rule & 0x7f) rule = { c for i, c in enumerate(('u', 'l', 's', 'd')) if (rule >> 7) & (1 << i) } self.cb(bin2pass.derive(rwd, rule, size).decode())
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 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 prepare_pack_recipient_keys(to_verkeys: Sequence[bytes], from_verkey: bytes = None, from_sigkey: bytes = None) -> (str, bytes): """ Assemble the recipients block of a packed message. Args: to_verkeys: Verkeys of recipients from_verkey: Sender Verkey needed to authcrypt package from_sigkey: Sender Sigkey needed to authcrypt package Returns: A tuple of (json result, key) """ if from_verkey is not None and from_sigkey is None or \ from_sigkey is not None and from_verkey is None: raise CryptoError( 'Both verkey and sigkey needed to authenticated encrypt message') cek = pysodium.crypto_secretstream_xchacha20poly1305_keygen() recips = [] for target_vk in to_verkeys: target_pk = pysodium.crypto_sign_pk_to_box_pk(target_vk) if from_verkey: sender_vk = bytes_to_b58(from_verkey).encode("ascii") enc_sender = pysodium.crypto_box_seal(sender_vk, target_pk) sk = pysodium.crypto_sign_sk_to_box_sk(from_sigkey) nonce = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES) enc_cek = pysodium.crypto_box(cek, nonce, target_pk, sk) else: enc_sender = None nonce = None enc_cek = pysodium.crypto_box_seal(cek, target_pk) recips.append( OrderedDict([ ("encrypted_key", bytes_to_b64(enc_cek, urlsafe=True)), ( "header", OrderedDict([ ("kid", bytes_to_b58(target_vk)), ( "sender", bytes_to_b64(enc_sender, urlsafe=True) if enc_sender else None, ), ( "iv", bytes_to_b64(nonce, urlsafe=True) if nonce else None, ), ]), ), ])) data = OrderedDict([ ("enc", "xchacha20poly1305_ietf"), ("typ", "JWM/1.0"), ("alg", "Authcrypt" if from_verkey else "Anoncrypt"), ("recipients", recips), ]) return json.dumps(data), cek
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")