go-sike/tools/sidh.sage

# P434
e2 = 0xD8
e3 = 0x89
# P503
# e2=0xFA
# e3=0x9F
#e2=0x174
#e3=0xEF

Nsk2_max_val = (2^e2) - 1
Nsk2_bytes = floor(e2/8)
Nsk3_S = ceil(RDF(log(3^e3,2)))
Nsk3_bytes = floor(Nsk3_S/8)
Nsk3_max_val = (2^Nsk3_S) - 1

p = 2^e2 * 3^e3 - 1
Fp = GF(p)
R.<x> = Fp[]
Fp2 = Fp.extension(x^2 + 1, 'i')
i = Fp2.gen()
E0Fp = EllipticCurve(Fp, [0,6,0,1,0])
E0Fp2 = EllipticCurve(Fp2, [0,6,0,1,0])

# Montgomery R
# 448 = 7*(8*8)
R = 2^448
# P503
# R = 2^512

def calc_Y_in_Fp2(x, xi):
    fp2X= Fp2(x+xi*i)
    fp2Y2 = Fp2(fp2X^3 + fp2X)
    ret = fp2Y2.sqrt()
    return ret

def calc_proj_point_A(fp2X, fp2Y): return (3^e3 * E0Fp2((fp2X, fp2Y)))
def calc_proj_point_B(fp2X, fp2Y): return (2^e2 * E0Fp2(fp2X, fp2Y))
              
def tau(P): return E0Fp2(-P.xy()[0], i*P.xy()[1])
def hd(val): 
    return ", 0x".join([x.hex().upper() for x in Integer(val).digits(base=2^64)])    
def hcp(point):
    print("X: "); hd(point[0])
    print("Y: "); hd(point[1])
    print("Z: "); hd(point[2])
def print_fp2_hex(Fp2_el):
    fp2_pol = Fp2_el.polynomial()
    print("A: FpElement{0x" + hd(fp2_pol[1]) + "},")
    print("B: FpElement{0x" + hd(fp2_pol[0]) + "}}")

def print_fp2_in_mont_hex(Fp2_el, text):
    print(text)
    mul = Integer(R)*Fp2_el
    fp2_pol = mul.polynomial()
    print("A: FpElement{0x" + hd(fp2_pol[0]) + "},")
    print("B: FpElement{0x" + hd(fp2_pol[1]) + "}}")

Integer(2^4 - 1).digits(2)

print("\n            P =\n"+hd(p))
print("\n          pX2 =\n"+hd(2*p))
print("\n          p+1 =\n"+hd(p+1))
print("\n    R^2 mod p =\n"+hd((R^2) % p))
print("\n1/2 * R mod p =\n"+hd(((1/2)*R) % p))
print("\n      R mod p =\n"+hd(R % p))
print("\n  6 * R mod p =\n"+hd(((6*R) % p)))