goavalon/ec-signature-verify.py at master · san-lab/goavalon · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
import hashlib
from ecpy.curves import Curve, Point
from ecpy.keys import ECPublicKey, ECPrivateKey

cv = Curve.get_curve("Ed25519")
g = cv.generator
p = cv.field
l = cv.order

#message as a string
#pbkey as a point encoded as hexstring (32)
#signature as hexstring
def verify(message, pbkey, signature):
    # sign contains R i s (32 bytes each)
    # Verify:
    # R + hash(R+m)Pb == sG
    keybytes =  bytes.fromhex(pbkey)
    sigbytes = bytes.fromhex(signature)
    R = sigbytes[:32]
    s = sigbytes[32:]

    #calculate the hash
    h = hashlib.sha256()
    h.update(R)
    h.update(message.encode("utf-8"))

    hint = int.from_bytes(h.digest(),"little")


    si = int.from_bytes(s, "little")
    S = cv.mul_point(si,g)

    Rp = cv.decode_point(R)
    Pb = cv.decode_point(keybytes)
    X = cv.add_point(Rp, cv.mul_point(hint, Pb))
    # R + hash(R+m)Pb == sGoh sure sure
    return (X.eq(S))


def generateFromSeed(seed):
#TODO verify that the seed is 32 bytes
    h = hashlib.sha512()
    h.update(seed)
    dig64 = h.digest()

    #clamp
    dig64_barray = bytearray(dig64)

    dig64_barray[0] &= 248
    dig64_barray[31] &= 127
    dig64_barray[31] |= 64

    bytes_d64 = bytes(dig64_barray)

    dint = int.from_bytes(bytes_d64[:32], "little")

    pubPoint = cv.mul_point(dint,g)
    privkey = seed + cv.encode_point(pubPoint)

    return privkey

#pubKey is byte32
#message is bytes 32
#signature is bytes 64
def verifyEd(pubKey, message, signature):
    R = signature[:32]
    R_point = cv.decode_point(R)

    s = signature[32:]
    s_int = int.from_bytes(s,"little")
    s_point= cv.mul_point(s_int,g)

    h = hashlib.sha512()
    h.update(R + pubKey + message)
    x = h.digest()
    x_int = int.from_bytes(x, "little")

    A = cv.decode_point(pubKey)
    P1 = cv.mul_point(x_int,A)

    S_prime = cv.add_point(P1,R_point)

    return s_point.eq(S_prime)

#privKey is byte64
#message is bytes
def signEd(privKey, message):
    seed = privKey[:32]
    pubKey = privKey[32:]

    h = hashlib.sha512()
    h.update(seed)
    nonce = h.digest()[32:]

    h = hashlib.sha512()
    h.update(nonce+message)
    r = h.digest()
    r_int = int.from_bytes(r,"little")
    R = cv.mul_point(r_int,g)
    R_encoded = cv.encode_point(R)

    h = hashlib.sha512()
    h.update(R_encoded+pubKey+message)
    h_scalar = h.digest()
    int_h_scalar = int.from_bytes(h_scalar,"little")

    nonce_barray = bytearray(nonce)

    nonce_barray[0] &= 248
    nonce_barray[31] &= 127
    nonce_barray[31] |= 64

    bytes_nonce = bytes(nonce_barray)
    int_nonce = int.from_bytes(bytes_nonce, "little")

    int_s = (r_int + int_h_scalar*int_nonce) % l
    #s_bytes = int_s.to_bytes(32, "little")
    s_bytes = bytes(int_s)

    return R_encoded + s_bytes


#message as a string
#pbkey as a point encoded as hexstring (32)
#signature as hexstring
def verifyEd25519Signature(message, pbkey, signature):


#IssuerPublicKey = "6cc0580343356515c288897c68dad03a2063d1ea9c03c14af40174bef52d1503"
#IssuerSignature = "acd34a616765820fe6c57ff1ddcbcbed55667e141b99aa2e86f723e16060407a260bc1b4e61e0d763f025550ede2f65e2f87d348adfc9da9b81ded7d33f62008"
#Message =  "Przemek"+"333"+"Average account balance cert"+"25001 EUR"+"0042"
#
#v = verify(Message, IssuerPublicKey, IssuerSignature)
#print("Signature valid:", v)


#Testing generate from seed
seed = bytes([0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x00,0x00, 0x00, 0x00, 0x02])
privkey = generateFromSeed(seed)
privKey_bytes = bytes(privkey)
privKey_hex = privKey_bytes.hex()
pub_key = privkey[32:]
#print(privkey[:32])
#print(privkey[32:])
#print(privKey_hex)

#signing message 'Avalon'
#13e37be0bde224336d144ee13ec68fbf21994ea3124a4616bfaf9e88e9203c8808f036a8fcce8df201cf26c8f4c5a2d8c2a780fec64b60caa519e8b310490f0e

hex_signature = "13e37be0bde224336d144ee13ec68fbf21994ea3124a4616bfaf9e88e9203c8808f036a8fcce8df201cf26c8f4c5a2d8c2a780fec64b60caa519e8b310490f0e"
bytes_sig = bytes.fromhex(hex_signature)
message_bytes = "Avalon".encode('utf-8')
#print(bytes_sig)
#print(message_bytes)

result = verifyEd(pub_key, message_bytes, bytes_sig)
#print(result)

new_sig = signEd(privKey_bytes, message_bytes)
print(bytes_sig.hex())
print(new_sig.hex())

result2 = verifyEd(pub_key, message_bytes, new_sig)
print(result2)