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nobs/dh/csidh/consts.go
2019-02-12 21:28:37 +00:00

123 lines
3.2 KiB
Go

package csidh
// TODO: This all could simply go to read-only segment
// then any write will crash the program which
// is actually right thing to do
// P511
const (
pbits = 511
kPrimeCount = 74
// (2*5+1)^74 is roughly 2^256
expMax = int8(5)
// size of the limbs, pretty much hardcoded to 64-bit words
limbBitSize = 64
// size of the limbs in bytes
limbByteSize = limbBitSize >> 3
// Number of limbs for a field element
numWords = 8
// PrivateKeySize is a size of cSIDH/512 private key in bytes.
PrivateKeySize = 37
// PublicKeySize is a size of cSIDH/512 public key in bytes.
PublicKeySize = 64
// SharedSecretSize is a size of cSIDH/512 shared secret in bytes.
SharedSecretSize = 64
)
var (
// Elkies primes up to 374 + prime 587
// p = 4 * product(primes) - 1
primes = []uint64{
3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59,
61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137,
139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227,
229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313,
317, 331, 337, 347, 349, 353, 359, 367, 373, 587}
p = Fp{
0x1B81B90533C6C87B, 0xC2721BF457ACA835,
0x516730CC1F0B4F25, 0xA7AAC6C567F35507,
0x5AFBFCC69322C9CD, 0xB42D083AEDC88C42,
0xFC8AB0D15E3E4C4A, 0x65B48E8F740F89BF,
}
/* Montgomery R = 2^512 mod p */
// TODO: Change name (remove _)
fp_1 = Fp{
0xC8FC8DF598726F0A, 0x7B1BC81750A6AF95,
0x5D319E67C1E961B4, 0xB0AA7275301955F1,
0x4A080672D9BA6C64, 0x97A5EF8A246EE77B,
0x06EA9E5D4383676A, 0x3496E2E117E0EC80,
}
/* Montgomery R^2 mod p */
r_squared_mod_p = Fp{
0x36905B572FFC1724, 0x67086F4525F1F27D,
0x4FAF3FBFD22370CA, 0x192EA214BCC584B1,
0x5DAE03EE2F5DE3D0, 0x1E9248731776B371,
0xAD5F166E20E4F52D, 0x4ED759AEA6F3917E,
}
// -p^-1 mod 2^64
pNegInv = Fp{
0x66c1301f632e294d,
}
// (p-1)/2. Used as exponent, hence not in
// montgomery domain
pMin1By2 = Fp{
0x8DC0DC8299E3643D, 0xE1390DFA2BD6541A,
0xA8B398660F85A792, 0xD3D56362B3F9AA83,
0x2D7DFE63499164E6, 0x5A16841D76E44621,
0xFE455868AF1F2625, 0x32DA4747BA07C4DF,
}
// p-1 mod 2^64. Used as exponent, hence not
// in montgomery domain
pMin2 = Fp{
0x1B81B90533C6C879, 0xC2721BF457ACA835,
0x516730CC1F0B4F25, 0xA7AAC6C567F35507,
0x5AFBFCC69322C9CD, 0xB42D083AEDC88C42,
0xFC8AB0D15E3E4C4A, 0x65B48E8F740F89BF,
}
// 2 in Montgomery domain
two = Fp{
0x767762E5FD1E1599, 0x33C5743A49A0B6F6,
0x68FC0C0364C77443, 0xB9AA1E24F83F56DB,
0x3914101F20520EFB, 0x7B1ED6D95B1542B4,
0x114A8BE928C8828A, 0x03793732BBB24F40,
}
// -2 in Montgomery domain
minTwo = Fp{
0xA50A561F36A8B2E2, 0x8EACA7BA0E0BF13E,
0xE86B24C8BA43DAE2, 0xEE00A8A06FB3FE2B,
0x21E7ECA772D0BAD1, 0x390E316192B3498E,
0xEB4024E83575C9C0, 0x623B575CB85D3A7F,
}
// 4 in Montgomery domain
four = Fp{
0xECEEC5CBFA3C2B32, 0x678AE87493416DEC,
0xD1F81806C98EE886, 0x73543C49F07EADB6,
0x7228203E40A41DF7, 0xF63DADB2B62A8568,
0x229517D251910514, 0x06F26E6577649E80,
}
// TODO: Why exactly they are not in montgomery domain?
twoMinP = Fp{}
// NOT SURE ABOUT THOSE
// 4 * sqrt(p)
fourSqrtP = Fp{
0x17895E71E1A20B3F, 0x38D0CD95F8636A56,
0x142B9541E59682CD, 0x856F1399D91D6592,
0x0000000000000002,
}
)