package net.i2p.crypto.eddsa.math.ed25519;
import net.i2p.crypto.eddsa.math.ScalarOps;
import static net.i2p.crypto.eddsa.math.ed25519.Ed25519LittleEndianEncoding.load_3;
import static net.i2p.crypto.eddsa.math.ed25519.Ed25519LittleEndianEncoding.load_4;
/**
* 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]+...+256^63*s[63] = s
* <p>
* Output:
* s[0]+256*s[1]+...+256^31*s[31] = s mod q
* where q = 2^252 + 27742317777372353535851937790883648493.
*/
public byte[] reduce(byte[] s) {
// s0,..., s22 have 21 bits, s23 has 29 bits
long s0 = 0x1FFFFF & load_3(s, 0);
long s1 = 0x1FFFFF & (load_4(s, 2) >> 5);
long s2 = 0x1FFFFF & (load_3(s, 5) >> 2);
long s3 = 0x1FFFFF & (load_4(s, 7) >> 7);
long s4 = 0x1FFFFF & (load_4(s, 10) >> 4);
long s5 = 0x1FFFFF & (load_3(s, 13) >> 1);
long s6 = 0x1FFFFF & (load_4(s, 15) >> 6);
long s7 = 0x1FFFFF & (load_3(s, 18) >> 3);
long s8 = 0x1FFFFF & load_3(s, 21);
long s9 = 0x1FFFFF & (load_4(s, 23) >> 5);
long s10 = 0x1FFFFF & (load_3(s, 26) >> 2);
long s11 = 0x1FFFFF & (load_4(s, 28) >> 7);
long s12 = 0x1FFFFF & (load_4(s, 31) >> 4);
long s13 = 0x1FFFFF & (load_3(s, 34) >> 1);
long s14 = 0x1FFFFF & (load_4(s, 36) >> 6);
long s15 = 0x1FFFFF & (load_3(s, 39) >> 3);
long s16 = 0x1FFFFF & load_3(s, 42);
long s17 = 0x1FFFFF & (load_4(s, 44) >> 5);
long s18 = 0x1FFFFF & (load_3(s, 47) >> 2);
long s19 = 0x1FFFFF & (load_4(s, 49) >> 7);
long s20 = 0x1FFFFF & (load_4(s, 52) >> 4);
long s21 = 0x1FFFFF & (load_3(s, 55) >> 1);
long s22 = 0x1FFFFF & (load_4(s, 57) >> 6);
long s23 = (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;
/**
* Lots of magic numbers :)
* To understand what's going on below, note that
*
* (1) q = 2^252 + q0 where q0 = 27742317777372353535851937790883648493.
* (2) s11 is the coefficient of 2^(11*21), s23 is the coefficient of 2^(^23*21) and 2^252 = 2^((23-11) * 21)).
* (3) 2^252 congruent -q0 modulo q.
* (4) -q0 = 666643 * 2^0 + 470296 * 2^21 + 654183 * 2^(2*21) - 997805 * 2^(3*21) + 136657 * 2^(4*21) - 683901 * 2^(5*21)
*
* Thus
* s23 * 2^(23*11) = s23 * 2^(12*21) * 2^(11*21) = s3 * 2^252 * 2^(11*21) congruent
* s23 * (666643 * 2^0 + 470296 * 2^21 + 654183 * 2^(2*21) - 997805 * 2^(3*21) + 136657 * 2^(4*21) - 683901 * 2^(5*21)) * 2^(11*21) modulo q =
* s23 * (666643 * 2^(11*21) + 470296 * 2^(12*21) + 654183 * 2^(13*21) - 997805 * 2^(14*21) + 136657 * 2^(15*21) - 683901 * 2^(16*21)).
*
* The same procedure is then applied for s22,...,s18.
*/
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;
/**
* Time to reduce the coefficient in order not to get an overflow.
*/
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;
/**
* Continue with above procedure.
*/
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;
/**
* Reduce coefficients again.
*/
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;
}
/**
* Input:
* <p><ul>
* <li>a[0]+256*a[1]+...+256^31*a[31] = a
* <li>b[0]+256*b[1]+...+256^31*b[31] = b
* <li>c[0]+256*c[1]+...+256^31*c[31] = c
* </ul><p>
* Output:
* result[0]+256*result[1]+...+256^31*result[31] = (ab+c) mod 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 & load_3(a, 0);
long a1 = 0x1FFFFF & (load_4(a, 2) >> 5);
long a2 = 0x1FFFFF & (load_3(a, 5) >> 2);
long a3 = 0x1FFFFF & (load_4(a, 7) >> 7);
long a4 = 0x1FFFFF & (load_4(a, 10) >> 4);
long a5 = 0x1FFFFF & (load_3(a, 13) >> 1);
long a6 = 0x1FFFFF & (load_4(a, 15) >> 6);
long a7 = 0x1FFFFF & (load_3(a, 18) >> 3);
long a8 = 0x1FFFFF & load_3(a, 21);
long a9 = 0x1FFFFF & (load_4(a, 23) >> 5);
long a10 = 0x1FFFFF & (load_3(a, 26) >> 2);
long a11 = (load_4(a, 28) >> 7);
long b0 = 0x1FFFFF & load_3(b, 0);
long b1 = 0x1FFFFF & (load_4(b, 2) >> 5);
long b2 = 0x1FFFFF & (load_3(b, 5) >> 2);
long b3 = 0x1FFFFF & (load_4(b, 7) >> 7);
long b4 = 0x1FFFFF & (load_4(b, 10) >> 4);
long b5 = 0x1FFFFF & (load_3(b, 13) >> 1);
long b6 = 0x1FFFFF & (load_4(b, 15) >> 6);
long b7 = 0x1FFFFF & (load_3(b, 18) >> 3);
long b8 = 0x1FFFFF & load_3(b, 21);
long b9 = 0x1FFFFF & (load_4(b, 23) >> 5);
long b10 = 0x1FFFFF & (load_3(b, 26) >> 2);
long b11 = (load_4(b, 28) >> 7);
long c0 = 0x1FFFFF & load_3(c, 0);
long c1 = 0x1FFFFF & (load_4(c, 2) >> 5);
long c2 = 0x1FFFFF & (load_3(c, 5) >> 2);
long c3 = 0x1FFFFF & (load_4(c, 7) >> 7);
long c4 = 0x1FFFFF & (load_4(c, 10) >> 4);
long c5 = 0x1FFFFF & (load_3(c, 13) >> 1);
long c6 = 0x1FFFFF & (load_4(c, 15) >> 6);
long c7 = 0x1FFFFF & (load_3(c, 18) >> 3);
long c8 = 0x1FFFFF & load_3(c, 21);
long c9 = 0x1FFFFF & (load_4(c, 23) >> 5);
long c10 = 0x1FFFFF & (load_3(c, 26) >> 2);
long c11 = (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;
}
}