/* Galbraith & Scott Method */
static void gs(BIG u[4],BIG e)
{
int i,j;
BIG v[4],t,q;
DBIG d;
BIG_rcopy(q,CURVE_Order);
for (i=0;i<4;i++)
{
BIG_rcopy(t,CURVE_WB[i]);
BIG_mul(d,t,e);
BIG_ddiv(v[i],d,q);
BIG_zero(u[i]);
}
BIG_copy(u[0],e);
for (i=0;i<4;i++)
for (j=0;j<4;j++)
{
BIG_rcopy(t,CURVE_BB[j][i]);
BIG_modmul(t,v[j],t,q);
BIG_add(u[i],u[i],q);
BIG_sub(u[i],u[i],t);
BIG_mod(u[i],q);
}
return;
}
/* SU= 16 */
void BIG_fromBytes(BIG a,char *b)
{
int i;
BIG_zero(a);
for (i=0;i<MODBYTES;i++)
{
BIG_fshl(a,8); a[0]+=(int)(unsigned char)b[i];
//BIG_inc(a,(int)(unsigned char)b[i]); BIG_norm(a);
}
#ifdef DEBUG_NORM
a[NLEN]=0;
#endif
}
/* Galbraith & Scott Method */
static void gs(BIG u[4],BIG e)
{
int i;
#if CHOICE<BLS_CURVES
int j;
BIG v[4],t,q;
DBIG d;
BIG_rcopy(q,CURVE_Order);
for (i=0; i<4; i++)
{
BIG_rcopy(t,CURVE_WB[i]);
//BIG_norm(t); BIG_norm(e);
BIG_mul(d,t,e);
BIG_ddiv(v[i],d,q);
BIG_zero(u[i]);
}
BIG_copy(u[0],e);
for (i=0; i<4; i++)
for (j=0; j<4; j++)
{
BIG_rcopy(t,CURVE_BB[j][i]);
BIG_modmul(t,v[j],t,q);
BIG_add(u[i],u[i],q);
BIG_sub(u[i],u[i],t);
BIG_mod(u[i],q);
}
#else
BIG x,w;
BIG_rcopy(x,CURVE_Bnx);
BIG_copy(w,e);
for (i=0; i<4; i++)
{
BIG_copy(u[i],w);
BIG_mod(u[i],x);
BIG_sdiv(w,x);
}
#endif
return;
}
/* GLV method */
static void glv(BIG u[2],BIG e)
{
#if CHOICE<BLS_CURVES
int i,j;
BIG v[2],t,q;
DBIG d;
BIG_rcopy(q,CURVE_Order);
for (i=0; i<2; i++)
{
BIG_rcopy(t,CURVE_W[i]);
//BIG_norm(t); BIG_norm(e);
BIG_mul(d,t,e);
BIG_ddiv(v[i],d,q);
BIG_zero(u[i]);
}
BIG_copy(u[0],e);
for (i=0; i<2; i++)
for (j=0; j<2; j++)
{
BIG_rcopy(t,CURVE_SB[j][i]);
BIG_modmul(t,v[j],t,q);
BIG_add(u[i],u[i],q);
BIG_sub(u[i],u[i],t);
BIG_mod(u[i],q);
}
#else
// -(x^2).P = (Beta.x,y)
BIG x,x2,q;
BIG_rcopy(x,CURVE_Bnx);
BIG_smul(x2,x,x);
BIG_copy(u[0],e);
BIG_mod(u[0],x2);
BIG_copy(u[1],e);
BIG_sdiv(u[1],x2);
BIG_rcopy(q,CURVE_Order);
BIG_sub(u[1],q,u[1]);
#endif
return;
}
/* SU= 40 */
void BIG_smul(BIG c,BIG a,BIG b)
{
int i,j;
chunk carry;
BIG_norm(a);
BIG_norm(b);
BIG_zero(c);
for (i=0;i<NLEN;i++)
{
carry=0;
for (j=0;j<NLEN;j++)
if (i+j<NLEN) carry=muladd(a[i],b[j],carry,&c[i+j]);
}
#ifdef DEBUG_NORM
c[NLEN]=0;
#endif
}
/* r=x^n using XTR method on traces of FP12s */
void FP4_xtr_pow(FP4 *r,FP4 *x,BIG n)
{
int i,par,nb;
BIG v;
FP2 w;
FP4 t,a,b,c;
BIG_zero(v); BIG_inc(v,3);
FP2_from_BIG(&w,v);
FP4_from_FP2(&a,&w);
FP4_copy(&b,x);
FP4_xtr_D(&c,x);
BIG_norm(n); par=BIG_parity(n); BIG_copy(v,n); BIG_shr(v,1);
if (par==0) {BIG_dec(v,1); BIG_norm(v);}
nb=BIG_nbits(v);
for (i=nb-1;i>=0;i--)
{
if (!BIG_bit(v,i))
{
FP4_copy(&t,&b);
FP4_conj(x,x);
FP4_conj(&c,&c);
FP4_xtr_A(&b,&a,&b,x,&c);
FP4_conj(x,x);
FP4_xtr_D(&c,&t);
FP4_xtr_D(&a,&a);
}
else
{
FP4_conj(&t,&a);
FP4_xtr_D(&a,&b);
FP4_xtr_A(&b,&c,&b,x,&t);
FP4_xtr_D(&c,&c);
}
}
if (par==0) FP4_copy(r,&c);
else FP4_copy(r,&b);
FP4_reduce(r);
}
/* SU= 240 */
void FP4_pow(FP4 *r,FP4* a,BIG b)
{
FP4 w;
BIG z,zilch;
int bt;
BIG_zero(zilch);
BIG_norm(b);
BIG_copy(z,b);
FP4_copy(&w,a);
FP4_one(r);
while(1)
{
bt=BIG_parity(z);
BIG_shr(z,1);
if (bt) FP4_mul(r,r,&w);
if (BIG_comp(z,zilch)==0) break;
FP4_sqr(&w,&w);
}
FP4_reduce(r);
}
void FP12_pow4(FP12 *p,FP12 *q,BIG u[4])
{
int i,j,a[4],nb,m;
FP12 g[8],c,s[2];
BIG t[4],mt;
sign8 w[NLEN*BASEBITS+1];
for (i=0;i<4;i++)
BIG_copy(t[i],u[i]);
FP12_copy(&g[0],&q[0]); FP12_conj(&s[0],&q[1]); FP12_mul(&g[0],&s[0]); /* P/Q */
FP12_copy(&g[1],&g[0]);
FP12_copy(&g[2],&g[0]);
FP12_copy(&g[3],&g[0]);
FP12_copy(&g[4],&q[0]); FP12_mul(&g[4],&q[1]); /* P*Q */
FP12_copy(&g[5],&g[4]);
FP12_copy(&g[6],&g[4]);
FP12_copy(&g[7],&g[4]);
FP12_copy(&s[1],&q[2]); FP12_conj(&s[0],&q[3]); FP12_mul(&s[1],&s[0]); /* R/S */
FP12_conj(&s[0],&s[1]); FP12_mul(&g[1],&s[0]);
FP12_mul(&g[2],&s[1]);
FP12_mul(&g[5],&s[0]);
FP12_mul(&g[6],&s[1]);
FP12_copy(&s[1],&q[2]); FP12_mul(&s[1],&q[3]); /* R*S */
FP12_conj(&s[0],&s[1]); FP12_mul(&g[0],&s[0]);
FP12_mul(&g[3],&s[1]);
FP12_mul(&g[4],&s[0]);
FP12_mul(&g[7],&s[1]);
/* if power is even add 1 to power, and add q to correction */
FP12_one(&c);
BIG_zero(mt);
for (i=0;i<4;i++)
{
if (BIG_parity(t[i])==0)
{
BIG_inc(t[i],1); BIG_norm(t[i]);
FP12_mul(&c,&q[i]);
}
BIG_add(mt,mt,t[i]); BIG_norm(mt);
}
FP12_conj(&c,&c);
nb=1+BIG_nbits(mt);
/* convert exponent to signed 1-bit window */
for (j=0;j<nb;j++)
{
for (i=0;i<4;i++)
{
a[i]=BIG_lastbits(t[i],2)-2;
BIG_dec(t[i],a[i]); BIG_norm(t[i]);
BIG_fshr(t[i],1);
}
w[j]=8*a[0]+4*a[1]+2*a[2]+a[3];
}
w[nb]=8*BIG_lastbits(t[0],2)+4*BIG_lastbits(t[1],2)+2*BIG_lastbits(t[2],2)+BIG_lastbits(t[3],2);
FP12_copy(p,&g[(w[nb]-1)/2]);
for (i=nb-1;i>=0;i--)
{
m=w[i]>>7;
j=(w[i]^m)-m; /* j=abs(w[i]) */
j=(j-1)/2;
FP12_copy(&s[0],&g[j]);
FP12_conj(&s[1],&g[j]);
FP12_usqr(p,p);
FP12_mul(p,&s[m&1]);
}
FP12_mul(p,&c); /* apply correction */
FP12_reduce(p);
}
