22 lines
529 B
Plaintext
22 lines
529 B
Plaintext
|
import "utils/pack/bool/nonStrictUnpack256" as unpack256;
|
||
|
|
|
||
|
|
// Compress JubJub Curve Point to 256bit array using big endianness bit order
|
||
|
|
// Python reference code from pycrypto:
|
||
|
|
// def compress(self):
|
||
|
|
// x = self.x.n
|
||
|
|
// y = self.y.n
|
||
|
|
// return int.to_bytes(y | ((x & 1) << 255), 32, "big")
|
||
|
|
|
||
|
|
def main(field[2] pt) -> bool[256] {
|
||
|
|
field x = pt[0];
|
||
|
|
field y = pt[1];
|
||
|
|
|
||
|
|
bool[256] xBits = unpack256(x);
|
||
|
|
bool[256] mut yBits = unpack256(y);
|
||
|
|
|
||
|
|
bool sign = xBits[255];
|
||
|
|
yBits[0] = sign;
|
||
|
|
|
||
|
|
return yBits;
|
||
|
|
}
|