/**
 * EdDSA-Java by str4d
 *
 * <p>To the extent possible under law, the person who associated CC0 with EdDSA-Java has waived all
 * copyright and related or neighboring rights to EdDSA-Java.
 *
 * <p>You should have received a copy of the CC0 legalcode along with this work. If not, see
 * <https://creativecommons.org/publicdomain/zero/1.0/>.
 */
package org.mariadb.jdbc.plugin.authentication.standard.ed25519.math.ed25519;

import org.mariadb.jdbc.plugin.authentication.standard.ed25519.math.ScalarOps;

/**
 * Class for reducing a huge integer modulo the group order q and doing a combined multiply plus add
 * plus reduce operation.
 *
 * <p>$q = 2^{252} + 27742317777372353535851937790883648493$.
 *
 * <p>Reviewed/commented by Bloody Rookie (nemproject@gmx.de)
 */
public class Ed25519ScalarOps implements ScalarOps {

  /**
   * Reduction modulo the group order $q$.
   *
   * <p>Input: $s[0]+256*s[1]+\dots+256^{63}*s[63] = s$
   *
   * <p>Output: $s[0]+256*s[1]+\dots+256^{31}*s[31] = s \bmod q$ where $q = 2^{252} +
   * 27742317777372353535851937790883648493$.
   */
  public byte[] reduce(byte[] s) {
    // s0,..., s22 have 21 bits, s23 has 29 bits
    long s0 = 0x1FFFFF & Ed25519LittleEndianEncoding.load_3(s, 0);
    long s1 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(s, 2) >> 5);
    long s2 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(s, 5) >> 2);
    long s3 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(s, 7) >> 7);
    long s4 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(s, 10) >> 4);
    long s5 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(s, 13) >> 1);
    long s6 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(s, 15) >> 6);
    long s7 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(s, 18) >> 3);
    long s8 = 0x1FFFFF & Ed25519LittleEndianEncoding.load_3(s, 21);
    long s9 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(s, 23) >> 5);
    long s10 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(s, 26) >> 2);
    long s11 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(s, 28) >> 7);
    long s12 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(s, 31) >> 4);
    long s13 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(s, 34) >> 1);
    long s14 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(s, 36) >> 6);
    long s15 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(s, 39) >> 3);
    long s16 = 0x1FFFFF & Ed25519LittleEndianEncoding.load_3(s, 42);
    long s17 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(s, 44) >> 5);
    long s18 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(s, 47) >> 2);
    long s19 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(s, 49) >> 7);
    long s20 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(s, 52) >> 4);
    long s21 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(s, 55) >> 1);
    long s22 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(s, 57) >> 6);
    long s23 = (Ed25519LittleEndianEncoding.load_4(s, 60) >> 3);
    long carry0;
    long carry1;
    long carry2;
    long carry3;
    long carry4;
    long carry5;
    long carry6;
    long carry7;
    long carry8;
    long carry9;
    long carry10;
    long carry11;
    long carry12;
    long carry13;
    long carry14;
    long carry15;
    long carry16;

    s11 += s23 * 666643;
    s12 += s23 * 470296;
    s13 += s23 * 654183;
    s14 -= s23 * 997805;
    s15 += s23 * 136657;
    s16 -= s23 * 683901;
    // not used again
    // s23 = 0;

    s10 += s22 * 666643;
    s11 += s22 * 470296;
    s12 += s22 * 654183;
    s13 -= s22 * 997805;
    s14 += s22 * 136657;
    s15 -= s22 * 683901;
    // not used again
    // s22 = 0;

    s9 += s21 * 666643;
    s10 += s21 * 470296;
    s11 += s21 * 654183;
    s12 -= s21 * 997805;
    s13 += s21 * 136657;
    s14 -= s21 * 683901;
    // not used again
    // s21 = 0;

    s8 += s20 * 666643;
    s9 += s20 * 470296;
    s10 += s20 * 654183;
    s11 -= s20 * 997805;
    s12 += s20 * 136657;
    s13 -= s20 * 683901;
    // not used again
    // s20 = 0;

    s7 += s19 * 666643;
    s8 += s19 * 470296;
    s9 += s19 * 654183;
    s10 -= s19 * 997805;
    s11 += s19 * 136657;
    s12 -= s19 * 683901;
    // not used again
    // s19 = 0;

    s6 += s18 * 666643;
    s7 += s18 * 470296;
    s8 += s18 * 654183;
    s9 -= s18 * 997805;
    s10 += s18 * 136657;
    s11 -= s18 * 683901;
    // not used again
    // s18 = 0;

    carry6 = (s6 + (1 << 20)) >> 21;
    s7 += carry6;
    s6 -= carry6 << 21;
    carry8 = (s8 + (1 << 20)) >> 21;
    s9 += carry8;
    s8 -= carry8 << 21;
    carry10 = (s10 + (1 << 20)) >> 21;
    s11 += carry10;
    s10 -= carry10 << 21;
    carry12 = (s12 + (1 << 20)) >> 21;
    s13 += carry12;
    s12 -= carry12 << 21;
    carry14 = (s14 + (1 << 20)) >> 21;
    s15 += carry14;
    s14 -= carry14 << 21;
    carry16 = (s16 + (1 << 20)) >> 21;
    s17 += carry16;
    s16 -= carry16 << 21;

    carry7 = (s7 + (1 << 20)) >> 21;
    s8 += carry7;
    s7 -= carry7 << 21;
    carry9 = (s9 + (1 << 20)) >> 21;
    s10 += carry9;
    s9 -= carry9 << 21;
    carry11 = (s11 + (1 << 20)) >> 21;
    s12 += carry11;
    s11 -= carry11 << 21;
    carry13 = (s13 + (1 << 20)) >> 21;
    s14 += carry13;
    s13 -= carry13 << 21;
    carry15 = (s15 + (1 << 20)) >> 21;
    s16 += carry15;
    s15 -= carry15 << 21;

    s5 += s17 * 666643;
    s6 += s17 * 470296;
    s7 += s17 * 654183;
    s8 -= s17 * 997805;
    s9 += s17 * 136657;
    s10 -= s17 * 683901;
    // not used again
    // s17 = 0;

    s4 += s16 * 666643;
    s5 += s16 * 470296;
    s6 += s16 * 654183;
    s7 -= s16 * 997805;
    s8 += s16 * 136657;
    s9 -= s16 * 683901;
    // not used again
    // s16 = 0;

    s3 += s15 * 666643;
    s4 += s15 * 470296;
    s5 += s15 * 654183;
    s6 -= s15 * 997805;
    s7 += s15 * 136657;
    s8 -= s15 * 683901;
    // not used again
    // s15 = 0;

    s2 += s14 * 666643;
    s3 += s14 * 470296;
    s4 += s14 * 654183;
    s5 -= s14 * 997805;
    s6 += s14 * 136657;
    s7 -= s14 * 683901;
    // not used again
    // s14 = 0;

    s1 += s13 * 666643;
    s2 += s13 * 470296;
    s3 += s13 * 654183;
    s4 -= s13 * 997805;
    s5 += s13 * 136657;
    s6 -= s13 * 683901;
    // not used again
    // s13 = 0;

    s0 += s12 * 666643;
    s1 += s12 * 470296;
    s2 += s12 * 654183;
    s3 -= s12 * 997805;
    s4 += s12 * 136657;
    s5 -= s12 * 683901;
    // set below
    // s12 = 0;

    carry0 = (s0 + (1 << 20)) >> 21;
    s1 += carry0;
    s0 -= carry0 << 21;
    carry2 = (s2 + (1 << 20)) >> 21;
    s3 += carry2;
    s2 -= carry2 << 21;
    carry4 = (s4 + (1 << 20)) >> 21;
    s5 += carry4;
    s4 -= carry4 << 21;
    carry6 = (s6 + (1 << 20)) >> 21;
    s7 += carry6;
    s6 -= carry6 << 21;
    carry8 = (s8 + (1 << 20)) >> 21;
    s9 += carry8;
    s8 -= carry8 << 21;
    carry10 = (s10 + (1 << 20)) >> 21;
    s11 += carry10;
    s10 -= carry10 << 21;

    carry1 = (s1 + (1 << 20)) >> 21;
    s2 += carry1;
    s1 -= carry1 << 21;
    carry3 = (s3 + (1 << 20)) >> 21;
    s4 += carry3;
    s3 -= carry3 << 21;
    carry5 = (s5 + (1 << 20)) >> 21;
    s6 += carry5;
    s5 -= carry5 << 21;
    carry7 = (s7 + (1 << 20)) >> 21;
    s8 += carry7;
    s7 -= carry7 << 21;
    carry9 = (s9 + (1 << 20)) >> 21;
    s10 += carry9;
    s9 -= carry9 << 21;
    // carry11 = (s11 + (1<<20)) >> 21; s12 += carry11; s11 -= carry11 << 21;
    carry11 = (s11 + (1 << 20)) >> 21;
    s12 = carry11;
    s11 -= carry11 << 21;

    s0 += s12 * 666643;
    s1 += s12 * 470296;
    s2 += s12 * 654183;
    s3 -= s12 * 997805;
    s4 += s12 * 136657;
    s5 -= s12 * 683901;
    // set below
    // s12 = 0;

    carry0 = s0 >> 21;
    s1 += carry0;
    s0 -= carry0 << 21;
    carry1 = s1 >> 21;
    s2 += carry1;
    s1 -= carry1 << 21;
    carry2 = s2 >> 21;
    s3 += carry2;
    s2 -= carry2 << 21;
    carry3 = s3 >> 21;
    s4 += carry3;
    s3 -= carry3 << 21;
    carry4 = s4 >> 21;
    s5 += carry4;
    s4 -= carry4 << 21;
    carry5 = s5 >> 21;
    s6 += carry5;
    s5 -= carry5 << 21;
    carry6 = s6 >> 21;
    s7 += carry6;
    s6 -= carry6 << 21;
    carry7 = s7 >> 21;
    s8 += carry7;
    s7 -= carry7 << 21;
    carry8 = s8 >> 21;
    s9 += carry8;
    s8 -= carry8 << 21;
    carry9 = s9 >> 21;
    s10 += carry9;
    s9 -= carry9 << 21;
    carry10 = s10 >> 21;
    s11 += carry10;
    s10 -= carry10 << 21;
    // carry11 = s11 >> 21; s12 += carry11; s11 -= carry11 << 21;
    carry11 = s11 >> 21;
    s12 = carry11;
    s11 -= carry11 << 21;

    // TODO-CR BR: Is it really needed to do it TWO times? (it doesn't hurt, just a question).
    s0 += s12 * 666643;
    s1 += s12 * 470296;
    s2 += s12 * 654183;
    s3 -= s12 * 997805;
    s4 += s12 * 136657;
    s5 -= s12 * 683901;
    // not used again
    // s12 = 0;

    carry0 = s0 >> 21;
    s1 += carry0;
    s0 -= carry0 << 21;
    carry1 = s1 >> 21;
    s2 += carry1;
    s1 -= carry1 << 21;
    carry2 = s2 >> 21;
    s3 += carry2;
    s2 -= carry2 << 21;
    carry3 = s3 >> 21;
    s4 += carry3;
    s3 -= carry3 << 21;
    carry4 = s4 >> 21;
    s5 += carry4;
    s4 -= carry4 << 21;
    carry5 = s5 >> 21;
    s6 += carry5;
    s5 -= carry5 << 21;
    carry6 = s6 >> 21;
    s7 += carry6;
    s6 -= carry6 << 21;
    carry7 = s7 >> 21;
    s8 += carry7;
    s7 -= carry7 << 21;
    carry8 = s8 >> 21;
    s9 += carry8;
    s8 -= carry8 << 21;
    carry9 = s9 >> 21;
    s10 += carry9;
    s9 -= carry9 << 21;
    carry10 = s10 >> 21;
    s11 += carry10;
    s10 -= carry10 << 21;

    // s0, ..., s11 got 21 bits each.
    byte[] result = new byte[32];
    result[0] = (byte) s0;
    result[1] = (byte) (s0 >> 8);
    result[2] = (byte) ((s0 >> 16) | (s1 << 5));
    result[3] = (byte) (s1 >> 3);
    result[4] = (byte) (s1 >> 11);
    result[5] = (byte) ((s1 >> 19) | (s2 << 2));
    result[6] = (byte) (s2 >> 6);
    result[7] = (byte) ((s2 >> 14) | (s3 << 7));
    result[8] = (byte) (s3 >> 1);
    result[9] = (byte) (s3 >> 9);
    result[10] = (byte) ((s3 >> 17) | (s4 << 4));
    result[11] = (byte) (s4 >> 4);
    result[12] = (byte) (s4 >> 12);
    result[13] = (byte) ((s4 >> 20) | (s5 << 1));
    result[14] = (byte) (s5 >> 7);
    result[15] = (byte) ((s5 >> 15) | (s6 << 6));
    result[16] = (byte) (s6 >> 2);
    result[17] = (byte) (s6 >> 10);
    result[18] = (byte) ((s6 >> 18) | (s7 << 3));
    result[19] = (byte) (s7 >> 5);
    result[20] = (byte) (s7 >> 13);
    result[21] = (byte) s8;
    result[22] = (byte) (s8 >> 8);
    result[23] = (byte) ((s8 >> 16) | (s9 << 5));
    result[24] = (byte) (s9 >> 3);
    result[25] = (byte) (s9 >> 11);
    result[26] = (byte) ((s9 >> 19) | (s10 << 2));
    result[27] = (byte) (s10 >> 6);
    result[28] = (byte) ((s10 >> 14) | (s11 << 7));
    result[29] = (byte) (s11 >> 1);
    result[30] = (byte) (s11 >> 9);
    result[31] = (byte) (s11 >> 17);
    return result;
  }

  /**
   * $(ab+c) \bmod q$
   *
   * <p>Input:
   *
   * <ul>
   *   <li>$a[0]+256*a[1]+\dots+256^{31}*a[31] = a$
   *   <li>$b[0]+256*b[1]+\dots+256^{31}*b[31] = b$
   *   <li>$c[0]+256*c[1]+\dots+256^{31}*c[31] = c$
   * </ul>
   *
   * <p>Output: $result[0]+256*result[1]+\dots+256^{31}*result[31] = (ab+c) \bmod q$ where $q =
   * 2^{252} + 27742317777372353535851937790883648493$.
   *
   * <p>See the comments in {@link #reduce(byte[])} for an explanation of the algorithm.
   */
  public byte[] multiplyAndAdd(byte[] a, byte[] b, byte[] c) {
    long a0 = 0x1FFFFF & Ed25519LittleEndianEncoding.load_3(a, 0);
    long a1 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(a, 2) >> 5);
    long a2 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(a, 5) >> 2);
    long a3 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(a, 7) >> 7);
    long a4 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(a, 10) >> 4);
    long a5 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(a, 13) >> 1);
    long a6 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(a, 15) >> 6);
    long a7 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(a, 18) >> 3);
    long a8 = 0x1FFFFF & Ed25519LittleEndianEncoding.load_3(a, 21);
    long a9 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(a, 23) >> 5);
    long a10 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(a, 26) >> 2);
    long a11 = (Ed25519LittleEndianEncoding.load_4(a, 28) >> 7);
    long b0 = 0x1FFFFF & Ed25519LittleEndianEncoding.load_3(b, 0);
    long b1 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(b, 2) >> 5);
    long b2 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(b, 5) >> 2);
    long b3 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(b, 7) >> 7);
    long b4 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(b, 10) >> 4);
    long b5 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(b, 13) >> 1);
    long b6 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(b, 15) >> 6);
    long b7 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(b, 18) >> 3);
    long b8 = 0x1FFFFF & Ed25519LittleEndianEncoding.load_3(b, 21);
    long b9 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(b, 23) >> 5);
    long b10 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(b, 26) >> 2);
    long b11 = (Ed25519LittleEndianEncoding.load_4(b, 28) >> 7);
    long c0 = 0x1FFFFF & Ed25519LittleEndianEncoding.load_3(c, 0);
    long c1 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(c, 2) >> 5);
    long c2 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(c, 5) >> 2);
    long c3 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(c, 7) >> 7);
    long c4 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(c, 10) >> 4);
    long c5 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(c, 13) >> 1);
    long c6 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(c, 15) >> 6);
    long c7 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(c, 18) >> 3);
    long c8 = 0x1FFFFF & Ed25519LittleEndianEncoding.load_3(c, 21);
    long c9 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_4(c, 23) >> 5);
    long c10 = 0x1FFFFF & (Ed25519LittleEndianEncoding.load_3(c, 26) >> 2);
    long c11 = (Ed25519LittleEndianEncoding.load_4(c, 28) >> 7);
    long s0;
    long s1;
    long s2;
    long s3;
    long s4;
    long s5;
    long s6;
    long s7;
    long s8;
    long s9;
    long s10;
    long s11;
    long s12;
    long s13;
    long s14;
    long s15;
    long s16;
    long s17;
    long s18;
    long s19;
    long s20;
    long s21;
    long s22;
    long s23;
    long carry0;
    long carry1;
    long carry2;
    long carry3;
    long carry4;
    long carry5;
    long carry6;
    long carry7;
    long carry8;
    long carry9;
    long carry10;
    long carry11;
    long carry12;
    long carry13;
    long carry14;
    long carry15;
    long carry16;
    long carry17;
    long carry18;
    long carry19;
    long carry20;
    long carry21;
    long carry22;

    s0 = c0 + a0 * b0;
    s1 = c1 + a0 * b1 + a1 * b0;
    s2 = c2 + a0 * b2 + a1 * b1 + a2 * b0;
    s3 = c3 + a0 * b3 + a1 * b2 + a2 * b1 + a3 * b0;
    s4 = c4 + a0 * b4 + a1 * b3 + a2 * b2 + a3 * b1 + a4 * b0;
    s5 = c5 + a0 * b5 + a1 * b4 + a2 * b3 + a3 * b2 + a4 * b1 + a5 * b0;
    s6 = c6 + a0 * b6 + a1 * b5 + a2 * b4 + a3 * b3 + a4 * b2 + a5 * b1 + a6 * b0;
    s7 = c7 + a0 * b7 + a1 * b6 + a2 * b5 + a3 * b4 + a4 * b3 + a5 * b2 + a6 * b1 + a7 * b0;
    s8 =
        c8 + a0 * b8 + a1 * b7 + a2 * b6 + a3 * b5 + a4 * b4 + a5 * b3 + a6 * b2 + a7 * b1
            + a8 * b0;
    s9 =
        c9 + a0 * b9 + a1 * b8 + a2 * b7 + a3 * b6 + a4 * b5 + a5 * b4 + a6 * b3 + a7 * b2 + a8 * b1
            + a9 * b0;
    s10 =
        c10 + a0 * b10 + a1 * b9 + a2 * b8 + a3 * b7 + a4 * b6 + a5 * b5 + a6 * b4 + a7 * b3
            + a8 * b2 + a9 * b1 + a10 * b0;
    s11 =
        c11 + a0 * b11 + a1 * b10 + a2 * b9 + a3 * b8 + a4 * b7 + a5 * b6 + a6 * b5 + a7 * b4
            + a8 * b3 + a9 * b2 + a10 * b1 + a11 * b0;
    s12 =
        a1 * b11 + a2 * b10 + a3 * b9 + a4 * b8 + a5 * b7 + a6 * b6 + a7 * b5 + a8 * b4 + a9 * b3
            + a10 * b2 + a11 * b1;
    s13 =
        a2 * b11 + a3 * b10 + a4 * b9 + a5 * b8 + a6 * b7 + a7 * b6 + a8 * b5 + a9 * b4 + a10 * b3
            + a11 * b2;
    s14 =
        a3 * b11 + a4 * b10 + a5 * b9 + a6 * b8 + a7 * b7 + a8 * b6 + a9 * b5 + a10 * b4 + a11 * b3;
    s15 = a4 * b11 + a5 * b10 + a6 * b9 + a7 * b8 + a8 * b7 + a9 * b6 + a10 * b5 + a11 * b4;
    s16 = a5 * b11 + a6 * b10 + a7 * b9 + a8 * b8 + a9 * b7 + a10 * b6 + a11 * b5;
    s17 = a6 * b11 + a7 * b10 + a8 * b9 + a9 * b8 + a10 * b7 + a11 * b6;
    s18 = a7 * b11 + a8 * b10 + a9 * b9 + a10 * b8 + a11 * b7;
    s19 = a8 * b11 + a9 * b10 + a10 * b9 + a11 * b8;
    s20 = a9 * b11 + a10 * b10 + a11 * b9;
    s21 = a10 * b11 + a11 * b10;
    s22 = a11 * b11;
    // set below
    // s23 = 0;

    carry0 = (s0 + (1 << 20)) >> 21;
    s1 += carry0;
    s0 -= carry0 << 21;
    carry2 = (s2 + (1 << 20)) >> 21;
    s3 += carry2;
    s2 -= carry2 << 21;
    carry4 = (s4 + (1 << 20)) >> 21;
    s5 += carry4;
    s4 -= carry4 << 21;
    carry6 = (s6 + (1 << 20)) >> 21;
    s7 += carry6;
    s6 -= carry6 << 21;
    carry8 = (s8 + (1 << 20)) >> 21;
    s9 += carry8;
    s8 -= carry8 << 21;
    carry10 = (s10 + (1 << 20)) >> 21;
    s11 += carry10;
    s10 -= carry10 << 21;
    carry12 = (s12 + (1 << 20)) >> 21;
    s13 += carry12;
    s12 -= carry12 << 21;
    carry14 = (s14 + (1 << 20)) >> 21;
    s15 += carry14;
    s14 -= carry14 << 21;
    carry16 = (s16 + (1 << 20)) >> 21;
    s17 += carry16;
    s16 -= carry16 << 21;
    carry18 = (s18 + (1 << 20)) >> 21;
    s19 += carry18;
    s18 -= carry18 << 21;
    carry20 = (s20 + (1 << 20)) >> 21;
    s21 += carry20;
    s20 -= carry20 << 21;
    // carry22 = (s22 + (1<<20)) >> 21; s23 += carry22; s22 -= carry22 << 21;
    carry22 = (s22 + (1 << 20)) >> 21;
    s23 = carry22;
    s22 -= carry22 << 21;

    carry1 = (s1 + (1 << 20)) >> 21;
    s2 += carry1;
    s1 -= carry1 << 21;
    carry3 = (s3 + (1 << 20)) >> 21;
    s4 += carry3;
    s3 -= carry3 << 21;
    carry5 = (s5 + (1 << 20)) >> 21;
    s6 += carry5;
    s5 -= carry5 << 21;
    carry7 = (s7 + (1 << 20)) >> 21;
    s8 += carry7;
    s7 -= carry7 << 21;
    carry9 = (s9 + (1 << 20)) >> 21;
    s10 += carry9;
    s9 -= carry9 << 21;
    carry11 = (s11 + (1 << 20)) >> 21;
    s12 += carry11;
    s11 -= carry11 << 21;
    carry13 = (s13 + (1 << 20)) >> 21;
    s14 += carry13;
    s13 -= carry13 << 21;
    carry15 = (s15 + (1 << 20)) >> 21;
    s16 += carry15;
    s15 -= carry15 << 21;
    carry17 = (s17 + (1 << 20)) >> 21;
    s18 += carry17;
    s17 -= carry17 << 21;
    carry19 = (s19 + (1 << 20)) >> 21;
    s20 += carry19;
    s19 -= carry19 << 21;
    carry21 = (s21 + (1 << 20)) >> 21;
    s22 += carry21;
    s21 -= carry21 << 21;

    s11 += s23 * 666643;
    s12 += s23 * 470296;
    s13 += s23 * 654183;
    s14 -= s23 * 997805;
    s15 += s23 * 136657;
    s16 -= s23 * 683901;
    // not used again
    // s23 = 0;

    s10 += s22 * 666643;
    s11 += s22 * 470296;
    s12 += s22 * 654183;
    s13 -= s22 * 997805;
    s14 += s22 * 136657;
    s15 -= s22 * 683901;
    // not used again
    // s22 = 0;

    s9 += s21 * 666643;
    s10 += s21 * 470296;
    s11 += s21 * 654183;
    s12 -= s21 * 997805;
    s13 += s21 * 136657;
    s14 -= s21 * 683901;
    // not used again
    // s21 = 0;

    s8 += s20 * 666643;
    s9 += s20 * 470296;
    s10 += s20 * 654183;
    s11 -= s20 * 997805;
    s12 += s20 * 136657;
    s13 -= s20 * 683901;
    // not used again
    // s20 = 0;

    s7 += s19 * 666643;
    s8 += s19 * 470296;
    s9 += s19 * 654183;
    s10 -= s19 * 997805;
    s11 += s19 * 136657;
    s12 -= s19 * 683901;
    // not used again
    // s19 = 0;

    s6 += s18 * 666643;
    s7 += s18 * 470296;
    s8 += s18 * 654183;
    s9 -= s18 * 997805;
    s10 += s18 * 136657;
    s11 -= s18 * 683901;
    // not used again
    // s18 = 0;

    carry6 = (s6 + (1 << 20)) >> 21;
    s7 += carry6;
    s6 -= carry6 << 21;
    carry8 = (s8 + (1 << 20)) >> 21;
    s9 += carry8;
    s8 -= carry8 << 21;
    carry10 = (s10 + (1 << 20)) >> 21;
    s11 += carry10;
    s10 -= carry10 << 21;
    carry12 = (s12 + (1 << 20)) >> 21;
    s13 += carry12;
    s12 -= carry12 << 21;
    carry14 = (s14 + (1 << 20)) >> 21;
    s15 += carry14;
    s14 -= carry14 << 21;
    carry16 = (s16 + (1 << 20)) >> 21;
    s17 += carry16;
    s16 -= carry16 << 21;

    carry7 = (s7 + (1 << 20)) >> 21;
    s8 += carry7;
    s7 -= carry7 << 21;
    carry9 = (s9 + (1 << 20)) >> 21;
    s10 += carry9;
    s9 -= carry9 << 21;
    carry11 = (s11 + (1 << 20)) >> 21;
    s12 += carry11;
    s11 -= carry11 << 21;
    carry13 = (s13 + (1 << 20)) >> 21;
    s14 += carry13;
    s13 -= carry13 << 21;
    carry15 = (s15 + (1 << 20)) >> 21;
    s16 += carry15;
    s15 -= carry15 << 21;

    s5 += s17 * 666643;
    s6 += s17 * 470296;
    s7 += s17 * 654183;
    s8 -= s17 * 997805;
    s9 += s17 * 136657;
    s10 -= s17 * 683901;
    // not used again
    // s17 = 0;

    s4 += s16 * 666643;
    s5 += s16 * 470296;
    s6 += s16 * 654183;
    s7 -= s16 * 997805;
    s8 += s16 * 136657;
    s9 -= s16 * 683901;
    // not used again
    // s16 = 0;

    s3 += s15 * 666643;
    s4 += s15 * 470296;
    s5 += s15 * 654183;
    s6 -= s15 * 997805;
    s7 += s15 * 136657;
    s8 -= s15 * 683901;
    // not used again
    // s15 = 0;

    s2 += s14 * 666643;
    s3 += s14 * 470296;
    s4 += s14 * 654183;
    s5 -= s14 * 997805;
    s6 += s14 * 136657;
    s7 -= s14 * 683901;
    // not used again
    // s14 = 0;

    s1 += s13 * 666643;
    s2 += s13 * 470296;
    s3 += s13 * 654183;
    s4 -= s13 * 997805;
    s5 += s13 * 136657;
    s6 -= s13 * 683901;
    // not used again
    // s13 = 0;

    s0 += s12 * 666643;
    s1 += s12 * 470296;
    s2 += s12 * 654183;
    s3 -= s12 * 997805;
    s4 += s12 * 136657;
    s5 -= s12 * 683901;
    // set below
    // s12 = 0;

    carry0 = (s0 + (1 << 20)) >> 21;
    s1 += carry0;
    s0 -= carry0 << 21;
    carry2 = (s2 + (1 << 20)) >> 21;
    s3 += carry2;
    s2 -= carry2 << 21;
    carry4 = (s4 + (1 << 20)) >> 21;
    s5 += carry4;
    s4 -= carry4 << 21;
    carry6 = (s6 + (1 << 20)) >> 21;
    s7 += carry6;
    s6 -= carry6 << 21;
    carry8 = (s8 + (1 << 20)) >> 21;
    s9 += carry8;
    s8 -= carry8 << 21;
    carry10 = (s10 + (1 << 20)) >> 21;
    s11 += carry10;
    s10 -= carry10 << 21;

    carry1 = (s1 + (1 << 20)) >> 21;
    s2 += carry1;
    s1 -= carry1 << 21;
    carry3 = (s3 + (1 << 20)) >> 21;
    s4 += carry3;
    s3 -= carry3 << 21;
    carry5 = (s5 + (1 << 20)) >> 21;
    s6 += carry5;
    s5 -= carry5 << 21;
    carry7 = (s7 + (1 << 20)) >> 21;
    s8 += carry7;
    s7 -= carry7 << 21;
    carry9 = (s9 + (1 << 20)) >> 21;
    s10 += carry9;
    s9 -= carry9 << 21;
    // carry11 = (s11 + (1<<20)) >> 21; s12 += carry11; s11 -= carry11 << 21;
    carry11 = (s11 + (1 << 20)) >> 21;
    s12 = carry11;
    s11 -= carry11 << 21;

    s0 += s12 * 666643;
    s1 += s12 * 470296;
    s2 += s12 * 654183;
    s3 -= s12 * 997805;
    s4 += s12 * 136657;
    s5 -= s12 * 683901;
    // set below
    // s12 = 0;

    carry0 = s0 >> 21;
    s1 += carry0;
    s0 -= carry0 << 21;
    carry1 = s1 >> 21;
    s2 += carry1;
    s1 -= carry1 << 21;
    carry2 = s2 >> 21;
    s3 += carry2;
    s2 -= carry2 << 21;
    carry3 = s3 >> 21;
    s4 += carry3;
    s3 -= carry3 << 21;
    carry4 = s4 >> 21;
    s5 += carry4;
    s4 -= carry4 << 21;
    carry5 = s5 >> 21;
    s6 += carry5;
    s5 -= carry5 << 21;
    carry6 = s6 >> 21;
    s7 += carry6;
    s6 -= carry6 << 21;
    carry7 = s7 >> 21;
    s8 += carry7;
    s7 -= carry7 << 21;
    carry8 = s8 >> 21;
    s9 += carry8;
    s8 -= carry8 << 21;
    carry9 = s9 >> 21;
    s10 += carry9;
    s9 -= carry9 << 21;
    carry10 = s10 >> 21;
    s11 += carry10;
    s10 -= carry10 << 21;
    // carry11 = s11 >> 21; s12 += carry11; s11 -= carry11 << 21;
    carry11 = s11 >> 21;
    s12 = carry11;
    s11 -= carry11 << 21;

    s0 += s12 * 666643;
    s1 += s12 * 470296;
    s2 += s12 * 654183;
    s3 -= s12 * 997805;
    s4 += s12 * 136657;
    s5 -= s12 * 683901;
    // not used again
    // s12 = 0;

    carry0 = s0 >> 21;
    s1 += carry0;
    s0 -= carry0 << 21;
    carry1 = s1 >> 21;
    s2 += carry1;
    s1 -= carry1 << 21;
    carry2 = s2 >> 21;
    s3 += carry2;
    s2 -= carry2 << 21;
    carry3 = s3 >> 21;
    s4 += carry3;
    s3 -= carry3 << 21;
    carry4 = s4 >> 21;
    s5 += carry4;
    s4 -= carry4 << 21;
    carry5 = s5 >> 21;
    s6 += carry5;
    s5 -= carry5 << 21;
    carry6 = s6 >> 21;
    s7 += carry6;
    s6 -= carry6 << 21;
    carry7 = s7 >> 21;
    s8 += carry7;
    s7 -= carry7 << 21;
    carry8 = s8 >> 21;
    s9 += carry8;
    s8 -= carry8 << 21;
    carry9 = s9 >> 21;
    s10 += carry9;
    s9 -= carry9 << 21;
    carry10 = s10 >> 21;
    s11 += carry10;
    s10 -= carry10 << 21;

    byte[] result = new byte[32];
    result[0] = (byte) s0;
    result[1] = (byte) (s0 >> 8);
    result[2] = (byte) ((s0 >> 16) | (s1 << 5));
    result[3] = (byte) (s1 >> 3);
    result[4] = (byte) (s1 >> 11);
    result[5] = (byte) ((s1 >> 19) | (s2 << 2));
    result[6] = (byte) (s2 >> 6);
    result[7] = (byte) ((s2 >> 14) | (s3 << 7));
    result[8] = (byte) (s3 >> 1);
    result[9] = (byte) (s3 >> 9);
    result[10] = (byte) ((s3 >> 17) | (s4 << 4));
    result[11] = (byte) (s4 >> 4);
    result[12] = (byte) (s4 >> 12);
    result[13] = (byte) ((s4 >> 20) | (s5 << 1));
    result[14] = (byte) (s5 >> 7);
    result[15] = (byte) ((s5 >> 15) | (s6 << 6));
    result[16] = (byte) (s6 >> 2);
    result[17] = (byte) (s6 >> 10);
    result[18] = (byte) ((s6 >> 18) | (s7 << 3));
    result[19] = (byte) (s7 >> 5);
    result[20] = (byte) (s7 >> 13);
    result[21] = (byte) s8;
    result[22] = (byte) (s8 >> 8);
    result[23] = (byte) ((s8 >> 16) | (s9 << 5));
    result[24] = (byte) (s9 >> 3);
    result[25] = (byte) (s9 >> 11);
    result[26] = (byte) ((s9 >> 19) | (s10 << 2));
    result[27] = (byte) (s10 >> 6);
    result[28] = (byte) ((s10 >> 14) | (s11 << 7));
    result[29] = (byte) (s11 >> 1);
    result[30] = (byte) (s11 >> 9);
    result[31] = (byte) (s11 >> 17);
    return result;
  }
}