def test_crypto_box_open_afternm(self):
m = b"howdy"
pk, sk = pysodium.crypto_box_keypair()
k = pysodium.crypto_box_beforenm(pk, sk)
n = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES)
c = pysodium.crypto_box_afternm(m, n, k)
self.assertEqual(c, c)
plaintext = pysodium.crypto_box_open_afternm(c, n, k)
self.assertEqual(m, plaintext)
def test_crypto_box_open_afternm(self):
m = b"howdy"
pk, sk = pysodium.crypto_box_keypair()
k = pysodium.crypto_box_beforenm(pk, sk)
n = pysodium.randombytes(pysodium.crypto_box_NONCEBYTES)
c = pysodium.crypto_box_afternm(m, n, k)
self.assertEqual(c, c)
plaintext = pysodium.crypto_box_open_afternm(c, n, k)
self.assertEqual(m, plaintext)
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
"""