def bytes_to_ele(q, S):
a = ''
if (config.is_q_prime() and q % 2 == 1): # q为奇素数
a = 0
t = math.ceil(math.log(q, 2))
l = math.ceil(t / 8)
a = bytes_to_int(S)
if not (a >= 0 and a <= q - 1):
print(
"*** ERROR: 域元素须在区间[0, q-1]上 *** function：bytes_to_ele(q, S) ***"
)
return -1
elif config.is_q_power_of_two(): # q为2的幂
m = math.ceil(math.log(q, 2))
a = padding_0_to_length(a, m)
'''a = bytes_to_bits(S)
temp = a
a = ''
for i in range(0, 2):
a = a + temp[i]
for i in range(0, m-len(temp)+2):
a = a + '0'
for i in range(0, len(temp)-2):
a = a + temp[i+2]'''
if not len(a) - 2 == m:
print("*** ERROR: 域元素必须为长度为m的比特串 *** function：bytes_to_ele(q, S)")
return -1
else:
print("*** ERROR: q不满足奇素数或2的幂 *** function：bytes_to_ele(q, S) ***")
return -1
return a
def ele_to_int(a):
#print("--- 域元素到字节串的转换 ---")
x = 0
q = config.get_q()
if (config.is_q_prime() and q % 2 == 1): # q为奇素数
x = a
elif config.is_q_power_of_two(): # q为2的幂
if type(a) == str and a[0:2] == '0b':
m = math.log(q, 2)
if len(a) - 2 == m:
#a = a.replace('0b', '')
a = remove_0b_at_beginning(a)
for i in a:
x = x * 2 + int(i)
else:
print(
"*** ERROR: 域元素必须为长度为m的比特串 *** function：ele_to_int(a, q)")
return -1
else:
print("*** ERROR: 输入必须为比特串 *** function：ele_to_int(a, q) ***")
return -1
else:
print("*** ERROR: q不满足奇素数或2的幂 *** function：ele_to_int(a, q) ***")
return -1
return x
def bytes_to_point(a, b, S):
q = config.get_q()
l = math.ceil(math.log(q, 2) / 8)
PC = ''
X = []
Y = []
# a.
if len(S) == 2 * l + 1: #为压缩表示形式或者混合表示形式
PC = S[0]
for i in range(1, l + 1):
X.append(S[i])
for i in range(l + 1, 2 * l + 1):
Y.append(S[i])
elif len(S) == l + 1: #压缩表示形式
PC = S[0]
for i in range(1, l):
X.append(S[i])
else:
print('*** ERROR: wrong size function: bytes_to_point ***')
# b. 将X转换成与元素x
x = bytes_to_ele(q, X)
##### c. 压缩表示形式 #####
y1 = ''
# c.1 and c.2
if PC == 2:
y1 = '0'
elif PC == 3:
y1 = '1'
##### d. 未压缩表示形式 #####
elif PC == 4:
y = bytes_to_ele(q, Y)
##### e. 混合表示形式 #####
# e.1 and e.2
elif PC == 6 or 7:
y = bytes_to_ele(q, Y)
else:
print('ERROR in bytes_to_point')
# f.
result = 0
if (type(x) != type(1)):
x = int(x, 2)
if (type(y) != type(1)):
y = int(y, 2)
if (config.is_q_prime() and q % 2 == 1): # q为奇素数
if (y**2) % q != (x**3 + a * x + b) % q:
return -1
elif config.is_q_power_of_two():
if (y**2 + x * y) != (x**3 + a * x + b):
return -1
# g.
point = Point(x, y)
return point
def ele_to_bytes(a):
#print("--- 域元素到字节串的转换 ---")
S = []
q = config.get_q()
if (config.is_q_prime() and q % 2 == 1): # q为奇素数
if (a >= 0 and a <= q - 1):
t = math.ceil(math.log(q, 2))
l = math.ceil(t / 8)
S = int_to_bytes(a, l)
else:
print(
"*** ERROR: 域元素须在区间[0, q-1]上 *** function：ele_to_bytes(a) ***")
return -1
elif config.is_q_power_of_two(): # q为2的幂
if type(a) == str and a[0:2] == '0b':
m = math.ceil(math.log(q, 2))
a = padding_0_to_length(a, m)
'''temp = a
a = ''
for i in range(0, 2):
a = a + temp[i]
for i in range(0, m-len(temp)+2):
a = a + '0'
for i in range(0, len(temp)-2):
a = a + temp[i+2]'''
if len(a) - 2 == m:
S = bits_to_bytes(a)
else:
print("*** ERROR: 域元素必须为长度为m的比特串 *** function：ele_to_bytes(a)")
return -1
else:
print("*** ERROR: 输入必须为比特串 *** function：ele_to_bytes(a) ***")
return -1
else:
print("*** ERROR: q不满足奇素数或2的幂 *** function：ele_to_bytes(a) ***")
return -1
return S