/********************************************************************************************
* Supersingular Isogeny Key Encapsulation Library
*
* Abstract: supersingular isogeny parameters and generation of functions for P434
*********************************************************************************************/

#include "sikep434r3.h"

/* Encoding of field elements, elements over Z_order, elements over GF(p^2) and elliptic curve points:
 *
 * Elements over GF(p) and Z_order are encoded with the least significant octet (and digit) located at
 * the leftmost position (i.e., little endian format). Elements (a+b*i) over GF(p^2), where a and b are
 * defined over GF(p), are encoded as {a, b}, with a in the least significant position. Elliptic curve
 * points P = (x,y) are encoded as {x, y}, with x in the least significant position. Internally, the
 * number of digits used to represent all these elements is obtained by approximating the number of bits
 * to the immediately greater multiple of 32. For example, a 434-bit field element is represented with
 * Ceil(434 / 64) = 7 64-bit digits or Ceil(434 / 32) = 14 32-bit digits.
 *
 * Curve isogeny system "SIDHp434". Base curve: Montgomery curve By^2 = Cx^3 + Ax^2 + Cx defined over
 * GF(p434^2), where A=6, B=1, C=1 and p434 = 2^216*3^137-1 */

const uint64_t p434[S2N_SIKE_P434_R3_NWORDS64_FIELD] = {
        0xFFFFFFFFFFFFFFFF, 0xFFFFFFFFFFFFFFFF, 0xFFFFFFFFFFFFFFFF,
        0xFDC1767AE2FFFFFF, 0x7BC65C783158AEA3, 0x6CFC5FD681C52056,
        0x0002341F27177344
};

const uint64_t p434x2[S2N_SIKE_P434_R3_NWORDS64_FIELD] = {
        0xFFFFFFFFFFFFFFFE, 0xFFFFFFFFFFFFFFFF, 0xFFFFFFFFFFFFFFFF,
        0xFB82ECF5C5FFFFFF, 0xF78CB8F062B15D47, 0xD9F8BFAD038A40AC,
        0x0004683E4E2EE688
};

const uint64_t p434x4[S2N_SIKE_P434_R3_NWORDS64_FIELD] = {
        0xFFFFFFFFFFFFFFFC, 0xFFFFFFFFFFFFFFFF, 0xFFFFFFFFFFFFFFFF,
        0xF705D9EB8BFFFFFF, 0xEF1971E0C562BA8F, 0xB3F17F5A07148159,
        0x0008D07C9C5DCD11
};

const uint64_t p434p1[S2N_SIKE_P434_R3_NWORDS64_FIELD] = {
        0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
        0xFDC1767AE3000000, 0x7BC65C783158AEA3, 0x6CFC5FD681C52056,
        0x0002341F27177344
};

/* Alice's generator values {XPA0 + XPA1*i, XQA0 + xQA1*i, XRA0 + XRA1*i} in GF(p434^2),
 * expressed in Montgomery representation */
const uint64_t A_gen[6*S2N_SIKE_P434_R3_NWORDS64_FIELD] = {
        0x05ADF455C5C345BF, 0x91935C5CC767AC2B, 0xAFE4E879951F0257,
        0x70E792DC89FA27B1, 0xF797F526BB48C8CD, 0x2181DB6131AF621F,
        0x00000A1C08B1ECC4, /* XPA0 */

        0x74840EB87CDA7788, 0x2971AA0ECF9F9D0B, 0xCB5732BDF41715D5,
        0x8CD8E51F7AACFFAA, 0xA7F424730D7E419F, 0xD671EB919A179E8C,
        0x0000FFA26C5A924A, /* XPA1 */

        0xFEC6E64588B7273B, 0xD2A626D74CBBF1C6, 0xF8F58F07A78098C7,
        0xE23941F470841B03, 0x1B63EDA2045538DD, 0x735CFEB0FFD49215,
        0x0001C4CB77542876, /* XQA0 */

        0xADB0F733C17FFDD6, 0x6AFFBD037DA0A050, 0x680EC43DB144E02F,
        0x1E2E5D5FF524E374, 0xE2DDA115260E2995, 0xA6E4B552E2EDE508,
        0x00018ECCDDF4B53E, /* XQA1 */

        0x01BA4DB518CD6C7D, 0x2CB0251FE3CC0611, 0x259B0C6949A9121B,
        0x60E17AC16D2F82AD, 0x3AA41F1CE175D92D, 0x413FBE6A9B9BC4F3,
        0x00022A81D8D55643, /* XRA0 */

        0xB8ADBC70FC82E54A, 0xEF9CDDB0D5FADDED, 0x5820C734C80096A0,
        0x7799994BAA96E0E4, 0x044961599E379AF8, 0xDB2B94FBF09F27E2,
        0x0000B87FC716C0C6 /* XRA1 */
};

/* Bob's generator values {XPB0, XQB0, XRB0 + XRB1*i} in GF(p434^2), expressed in Montgomery representation */
const uint64_t B_gen[6*S2N_SIKE_P434_R3_NWORDS64_FIELD] = {
        0x6E5497556EDD48A3, 0x2A61B501546F1C05, 0xEB919446D049887D,
        0x5864A4A69D450C4F, 0xB883F276A6490D2B, 0x22CC287022D5F5B9,
        0x0001BED4772E551F, /* XPB0 */

        0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
        0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
        0x0000000000000000, /* XPB1 */

        0xFAE2A3F93D8B6B8E, 0x494871F51700FE1C, 0xEF1A94228413C27C,
        0x498FF4A4AF60BD62, 0xB00AD2A708267E8A, 0xF4328294E017837F,
        0x000034080181D8AE, /* XQB0 */

        0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
        0x0000000000000000, 0x0000000000000000, 0x0000000000000000,
        0x0000000000000000, /* XQB1 */

        0x283B34FAFEFDC8E4, 0x9208F44977C3E647, 0x7DEAE962816F4E9A,
        0x68A2BA8AA262EC9D, 0x8176F112EA43F45B, 0x02106D022634F504,
        0x00007E8A50F02E37, /* XRB0 */

        0xB378B7C1DA22CCB1, 0x6D089C99AD1D9230, 0xEBE15711813E2369,
        0x2B35A68239D48A53, 0x445F6FD138407C93, 0xBEF93B29A3F6B54B,
        0x000173FA910377D3 /* XRB1 */
};

/* Montgomery constant Montgomery_R2 = (2^448)^2 mod p434 */
const uint64_t Montgomery_R2[S2N_SIKE_P434_R3_NWORDS64_FIELD] = {
        0x28E55B65DCD69B30, 0xACEC7367768798C2, 0xAB27973F8311688D,
        0x175CC6AF8D6C7C0B, 0xABCD92BF2DDE347E, 0x69E16A61C7686D9A,
        0x000025A89BCDD12A
};

/* Value one in Montgomery representation */
const uint64_t Montgomery_one[S2N_SIKE_P434_R3_NWORDS64_FIELD] = {
        0x000000000000742C, 0x0000000000000000, 0x0000000000000000,
        0xB90FF404FC000000, 0xD801A4FB559FACD4, 0xE93254545F77410C,
        0x0000ECEEA7BD2EDA
};

/* Fixed parameters for isogeny tree computation */
const unsigned int strat_Alice[S2N_SIKE_P434_R3_MAX_ALICE-1] = {
        48, 28, 16, 8, 4, 2, 1, 1, 2, 1, 1, 4, 2, 1, 1, 2, 1, 1, 8, 4, 2, 1, 1, 2, 1, 1, 4, 2, 1, 1, 2, 1, 1, 13, 7, 4,
        2, 1, 1, 2, 1, 1, 3, 2, 1, 1, 1, 1, 5, 4, 2, 1, 1, 2, 1, 1, 2, 1, 1, 1, 21, 12, 7, 4, 2, 1, 1, 2, 1, 1, 3, 2,
        1, 1, 1, 1, 5, 3, 2, 1, 1, 1, 1, 2, 1, 1, 1, 9, 5, 3, 2, 1, 1, 1, 1, 2, 1, 1, 1, 4, 2, 1, 1, 1, 2, 1, 1
};

const unsigned int strat_Bob[S2N_SIKE_P434_R3_MAX_BOB-1] = {
        66, 33, 17, 9, 5, 3, 2, 1, 1, 1, 1, 2, 1, 1, 1, 4, 2, 1, 1, 1, 2, 1, 1, 8, 4, 2, 1, 1, 1, 2, 1, 1, 4, 2, 1, 1,
        2, 1, 1, 16, 8, 4, 2, 1, 1, 1, 2, 1, 1, 4, 2, 1, 1, 2, 1, 1, 8, 4, 2, 1, 1, 2, 1, 1, 4, 2, 1, 1, 2, 1, 1, 32,
        16, 8, 4, 3, 1, 1, 1, 1, 2, 1, 1, 4, 2, 1, 1, 2, 1, 1, 8, 4, 2, 1, 1, 2, 1, 1, 4, 2, 1, 1, 2, 1, 1, 16, 8, 4,
        2, 1, 1, 2, 1, 1, 4, 2, 1, 1, 2, 1, 1, 8, 4, 2, 1, 1, 2, 1, 1, 4, 2, 1, 1, 2, 1, 1
};

/* Returns true if the machine is big endian */
bool is_big_endian()
{
    uint16_t i = 1;
    uint8_t *ptr = (uint8_t *)&i;
    return !(*ptr);
}

uint32_t bswap32(uint32_t x)
{
    uint32_t i = (x >> 16) | (x << 16);
    return ((i & UINT32_C(0xff00ff00)) >> 8) | ((i & UINT32_C(0x00ff00ff)) << 8);
}

uint64_t bswap64(uint64_t x)
{
    return bswap32(x >> 32) | (((uint64_t)bswap32(x)) << 32);
}