def main():
N = 4 # Limited number of messages
# Generate 'N' private/public key pairs (Xi, Yi) from the Lamport signature scheme
key_pairs = [LamportSignature() for _ in range(N)
] # Private key of the Merkle signature scheme
# The leaves of the tree are the hashed values of the public keys Y0, ..., YN
mk = MerkleTree(n_leaves=N)
for i in range(N):
mk.add_node(key_pairs[i].get_key('public', concatenate=True), (0, i),
hashed=False)
# Build Merkle tree
mk.generate_tree()
pub = mk.get_root() # Public key of the Merkle signature scheme
# Merkle signature generation using a chosen pair of keys (Xi, Yi) from the Lamport signature scheme
# sig = concatenate(sig_prime, Yi, auth(0), ..., auth(n-1))
# see https://en.wikipedia.org/wiki/Merkle_signature_scheme
pair = 3 # (Xi, Yi) pair number
sig = []
M = "test"
sig_prime = key_pairs[pair].sign(M)
sig.append(sig_prime) # Add sig_prime to the signature 'sig'.
sig.append(key_pairs[pair].get_key(
'public', concatenate=True)) # Add Yi to the signature 'sig'.
sig.append(mk.get_authentification_path_hashes(
pair)) # Add auth(0), ..., auth(n-1) to the signature 'sig'.
# Send to receiver the public key 'pub' (tree root), the message 'M' and the Merkle signature 'sig'.
client = Client()
msg = (N, pair, pub, M, sig)
client.send(pickle.dumps(msg))
client.close()
def main():
N = 4 # Limited number of messages
# Generate 'N' private/public key pairs (Xi, Yi) from the Lamport signature scheme
key_pairs = [LamportSignature() for _ in range(N)
] # Private key of the Merkle signature scheme
# The leaves of the tree are the hashed values of the public keys Y0, ..., YN
mk = MerkleTree(n_leaves=N)
for i in range(N):
mk.add_node(key_pairs[i].get_key('public', concatenate=True), (0, i),
hashed=False)
# Build Merkle tree
mk.generate_tree()
pub = mk.get_root() # Public key of the Merkle signature scheme
# Merkle signature generation using a chosen pair of keys (Xi, Yi) from the Lamport signature scheme
# sig = concatenate(sig_prime, Yi, auth(0), ..., auth(n-1))
# see https://en.wikipedia.org/wiki/Merkle_signature_scheme
pair = 3 # (Xi, Yi) pair number
sig = []
M = "test"
sig_prime = key_pairs[pair].sign(M)
sig.append(sig_prime) # Add sig_prime to the signature 'sig'.
sig.append(key_pairs[pair].get_key(
'public', concatenate=True)) # Add Yi to the signature 'sig'.
sig.append(mk.get_authentification_path_hashes(
pair)) # Add auth(0), ..., auth(n-1) to the signature 'sig'.
######################################################################
# Merkle signature verification.
######################################################################
# Receiver knows the public key 'pub' (tree root), the message 'M' and the Merkle signature 'sig'.
pub_receiver = pub
M_receiver = M
sig_receiver = sig
# First, the receiver verifies the one time signature 'sig_prime' of the message 'M' using the Lamport key 'Yi'.
print("Check one time signature of the received message: " + M_receiver)
result = LamportSignature.verify(
M_receiver, sig_receiver[0],
LamportSignature.decatenate_key(sig_receiver[1]))
print("One-time signature is: " + str(result))
# If 'sig_prime' is a valid signature of 'M', the receiver computes the leaf corresponding to the Lamport key 'Yi'.
if result:
mk_receiver = MerkleTree(n_leaves=N)
mk_receiver.add_node(sig_receiver[1], (0, pair), hashed=False)
mk_receiver.generate_tree()
# The nodes of the authentification path are computed.
for i, (level, index) in enumerate(
mk_receiver.get_authentification_path(pair)):
mk_receiver.add_node(sig_receiver[2][i], (level, index),
hashed=True)
mk_receiver.generate_tree()
# If the tree's root equals the public key 'pub' the signature is valid.
result = mk_receiver.get_root() == pub_receiver
print("Merkle signature is: " + str(result))