From: anon <unknown>
Date: Sun, 8 Jun 2008 14:17:46 +0000 (+0800)
Subject: nagra-0101: fixed map3e
X-Git-Tag: 0.9.1~84
X-Git-Url: http://www.vanbest.org/gitweb/?a=commitdiff_plain;h=153fa0e79665544c648c70af758c07bb71c9adb8;p=sasc-ng.git

nagra-0101: fixed map3e
---

diff --git a/systems/nagra/nagra2-0101.c b/systems/nagra/nagra2-0101.c
index 5eac2f4..a8d4da4 100644
--- a/systems/nagra/nagra2-0101.c
+++ b/systems/nagra/nagra2-0101.c
@@ -238,14 +238,25 @@ fprintf(stderr,"map %x l=%d\n",f,l);
       break;
     case 0x3e:
       {
-      I.GetLE(data,l<<3);
-      BN_mod_exp(B,A,I,D,ctx);
-      BN_one(A);
-      int end=BN_num_bits(I);
+      cBN scalar;
+      scalar.GetLE(data,l<<3);
+      if(BN_is_zero(scalar) || BN_num_bits(D)<=1) {
+        MakeJ0(J,D);
+        if(BN_num_bits(D)==1 || !BN_is_zero(scalar)) BN_zero(B);
+        else BN_one(B);
+        BN_one(A);
+        }
+      else {
+        MonInit();
+        MonMul(B,A,B);
+        MonExp(scalar);
+        }
+      BN_zero(C);
+      int end=BN_num_bits(scalar);
       int msb=data[(end-1)/8];
       cycles=3848 + ((end-1)/8)*650 - 11;
       for(int i=8; --i>=1;) if(msb&(1<<i)) { cycles+=(i*75)-15; break; }
-      for(int i=end; --i>=0;) if(BN_is_bit_set(I,i)) cycles+=88;
+      for(int i=end; --i>=0;) if(BN_is_bit_set(scalar,i)) cycles+=88;
       break;
       }
     case 0x4d:
diff --git a/systems/nagra/nagra2.c b/systems/nagra/nagra2.c
index c3b6699..24c8c19 100644
--- a/systems/nagra/nagra2.c
+++ b/systems/nagra/nagra2.c
@@ -451,6 +451,18 @@ void cMapCore::MonInit(int bits)
   for(int i=0; i<4; i++) MonMul(B,B,B);
 }
 
+void cMapCore::MonExp(BIGNUM *scalar)
+{
+  if(BN_is_zero(D)) { BN_one(A); return; }
+  BN_copy(A,B);
+  for(int i=BN_num_bits(scalar)-2; i>-1; i--) {
+    MonMul(B,B,B);
+    if(BN_is_bit_set(scalar,i)) MonMul(B,A,B);
+    }
+  BN_one(A);
+  MonMul(B,A,B);
+}
+
 void cMapCore::MonExpNeg(void)
 {
   if(BN_is_zero(D)) { BN_set_word(A,1); return; }
diff --git a/systems/nagra/nagra2.h b/systems/nagra/nagra2.h
index 0e68e8a..30889aa 100644
--- a/systems/nagra/nagra2.h
+++ b/systems/nagra/nagra2.h
@@ -143,6 +143,7 @@ protected:
   cBN sA0, sC0, sE0, s100, s120, s140, s160;
   // statefull
   void MonInit(int bits=0);
+  void MonExp(BIGNUM *scalar);
   void MonExpNeg(void);
   // ECC
   void DoubleP(int temp);