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Diff for /src/usr.bin/ssh/sntrup761.c between version 1.5 and 1.6

version 1.5, 2021/01/08 02:33:13 version 1.6, 2023/01/11 02:13:52
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 Time still varies depending on m; user must ensure that m is constant.  Time still varies depending on m; user must ensure that m is constant.
 Time also varies on CPUs where multiplication is variable-time.  Time also varies on CPUs where multiplication is variable-time.
 There could be more CPU issues.  There could be more CPU issues.
 There could also be compiler issues.  There could also be compiler issues.
 */  */
   
 static void uint32_divmod_uint14(uint32 *q,uint16 *r,uint32 x,uint16 m)  static void uint32_divmod_uint14(uint32 *q,uint16 *r,uint32 x,uint16 m)
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 #ifndef LPR  #ifndef LPR
   
 static Fq Fq_recip(Fq a1)  static Fq Fq_recip(Fq a1)
 {  {
   int i = 1;    int i = 1;
   Fq ai = a1;    Fq ai = a1;
   
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     i += 1;      i += 1;
   }    }
   return ai;    return ai;
 }  }
   
 #endif  #endif
   
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 /* returns 0 if recip succeeded; else -1 */  /* returns 0 if recip succeeded; else -1 */
 static int R3_recip(small *out,const small *in)  static int R3_recip(small *out,const small *in)
 {  {
   small f[p+1],g[p+1],v[p+1],r[p+1];    small f[p+1],g[p+1],v[p+1],r[p+1];
   int i,loop,delta;    int i,loop,delta;
   int sign,swap,t;    int sign,swap,t;
   
   for (i = 0;i < p+1;++i) v[i] = 0;    for (i = 0;i < p+1;++i) v[i] = 0;
   for (i = 0;i < p+1;++i) r[i] = 0;    for (i = 0;i < p+1;++i) r[i] = 0;
   r[0] = 1;    r[0] = 1;
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   f[0] = 1; f[p-1] = f[p] = -1;    f[0] = 1; f[p-1] = f[p] = -1;
   for (i = 0;i < p;++i) g[p-1-i] = in[i];    for (i = 0;i < p;++i) g[p-1-i] = in[i];
   g[p] = 0;    g[p] = 0;
   
   delta = 1;  
   
     delta = 1;
   
   for (loop = 0;loop < 2*p-1;++loop) {    for (loop = 0;loop < 2*p-1;++loop) {
     for (i = p;i > 0;--i) v[i] = v[i-1];      for (i = p;i > 0;--i) v[i] = v[i-1];
     v[0] = 0;      v[0] = 0;
   
     sign = -g[0]*f[0];      sign = -g[0]*f[0];
     swap = int16_negative_mask(-delta) & int16_nonzero_mask(g[0]);      swap = int16_negative_mask(-delta) & int16_nonzero_mask(g[0]);
     delta ^= swap&(delta^-delta);      delta ^= swap&(delta^-delta);
     delta += 1;      delta += 1;
   
     for (i = 0;i < p+1;++i) {      for (i = 0;i < p+1;++i) {
       t = swap&(f[i]^g[i]); f[i] ^= t; g[i] ^= t;        t = swap&(f[i]^g[i]); f[i] ^= t; g[i] ^= t;
       t = swap&(v[i]^r[i]); v[i] ^= t; r[i] ^= t;        t = swap&(v[i]^r[i]); v[i] ^= t; r[i] ^= t;
     }      }
   
     for (i = 0;i < p+1;++i) g[i] = F3_freeze(g[i]+sign*f[i]);      for (i = 0;i < p+1;++i) g[i] = F3_freeze(g[i]+sign*f[i]);
     for (i = 0;i < p+1;++i) r[i] = F3_freeze(r[i]+sign*v[i]);      for (i = 0;i < p+1;++i) r[i] = F3_freeze(r[i]+sign*v[i]);
   
     for (i = 0;i < p;++i) g[i] = g[i+1];      for (i = 0;i < p;++i) g[i] = g[i+1];
     g[p] = 0;      g[p] = 0;
   }    }
   
   sign = f[0];    sign = f[0];
   for (i = 0;i < p;++i) out[i] = sign*v[p-1-i];    for (i = 0;i < p;++i) out[i] = sign*v[p-1-i];
   
   return int16_nonzero_mask(delta);    return int16_nonzero_mask(delta);
 }  }
   
 #endif  #endif
   
Line 599 
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 static void Rq_mult3(Fq *h,const Fq *f)  static void Rq_mult3(Fq *h,const Fq *f)
 {  {
   int i;    int i;
   
   for (i = 0;i < p;++i) h[i] = Fq_freeze(3*f[i]);    for (i = 0;i < p;++i) h[i] = Fq_freeze(3*f[i]);
 }  }
   
 /* out = 1/(3*in) in Rq */  /* out = 1/(3*in) in Rq */
 /* returns 0 if recip succeeded; else -1 */  /* returns 0 if recip succeeded; else -1 */
 static int Rq_recip3(Fq *out,const small *in)  static int Rq_recip3(Fq *out,const small *in)
 {  {
   Fq f[p+1],g[p+1],v[p+1],r[p+1];    Fq f[p+1],g[p+1],v[p+1],r[p+1];
   int i,loop,delta;    int i,loop,delta;
   int swap,t;    int swap,t;
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Line 735 
 {  {
   small g[p];    small g[p];
   Fq finv[p];    Fq finv[p];
   
   for (;;) {    for (;;) {
     Small_random(g);      Small_random(g);
     if (R3_recip(ginv,g) == 0) break;      if (R3_recip(ginv,g) == 0) break;
Line 773 
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   for (i = 0;i < w;++i) r[i] = ((ev[i]^1)&~mask)^1;    for (i = 0;i < w;++i) r[i] = ((ev[i]^1)&~mask)^1;
   for (i = w;i < p;++i) r[i] = ev[i]&~mask;    for (i = w;i < p;++i) r[i] = ev[i]&~mask;
 }  }
   
 #endif  #endif
   
 /* ----- NTRU LPRime Core */  /* ----- NTRU LPRime Core */
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   for (i = 0;i < I;++i)    for (i = 0;i < I;++i)
     r[i] = -int16_negative_mask(Fq_freeze(Right(T[i])-aB[i]+4*w+1));      r[i] = -int16_negative_mask(Fq_freeze(Right(T[i])-aB[i]+4*w+1));
 }  }
   
 #endif  #endif
   
 /* ----- encoding I-bit inputs */  /* ----- encoding I-bit inputs */
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 }  }
   
 #endif  #endif
   
 /* ----- NTRU LPRime Expand */  /* ----- NTRU LPRime Expand */
   
 #ifdef LPR  #ifdef LPR
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Line 970 
 {  {
   uint16 R[p],M[p];    uint16 R[p],M[p];
   int i;    int i;
   
   for (i = 0;i < p;++i) R[i] = r[i]+q12;    for (i = 0;i < p;++i) R[i] = r[i]+q12;
   for (i = 0;i < p;++i) M[i] = q;    for (i = 0;i < p;++i) M[i] = q;
   Encode(s,R,M,p);    Encode(s,R,M,p);
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Line 985 
   Decode(R,s,M,p);    Decode(R,s,M,p);
   for (i = 0;i < p;++i) r[i] = ((Fq)R[i])-q12;    for (i = 0;i < p;++i) r[i] = ((Fq)R[i])-q12;
 }  }
   
 #endif  #endif
   
 /* ----- encoding rounded polynomials */  /* ----- encoding rounded polynomials */
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Removed from v.1.5  
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  Added in v.1.6