29 lines
563 B
Python
29 lines
563 B
Python
q = 2**255 - 19
|
|
|
|
def expmod(b,e,m):
|
|
if e == 0: return 1
|
|
t = expmod(b,e/2,m)**2 % m
|
|
if e & 1: t = (t*b) % m
|
|
return t
|
|
|
|
def inv(x):
|
|
return expmod(x,q-2,q)
|
|
|
|
def radix255(x):
|
|
x = x % q
|
|
if x + x > q: x -= q
|
|
x = [x,0,0,0,0,0,0,0,0,0]
|
|
bits = [26,25,26,25,26,25,26,25,26,25]
|
|
for i in range(9):
|
|
carry = (x[i] + 2**(bits[i]-1)) / 2**bits[i]
|
|
x[i] -= carry * 2**bits[i]
|
|
x[i + 1] += carry
|
|
result = ""
|
|
for i in range(9):
|
|
result = result+str(x[i])+","
|
|
result = result+str(x[9])
|
|
return result
|
|
|
|
I = expmod(2,(q-1)/4,q)
|
|
print radix255(I)
|