1 files changed, 26 insertions, 52 deletions
diff --git a/src/block/idea/idea.cpp b/src/block/idea/idea.cpp
index fb5fe83f1..15ff7c0ec 100644
--- a/src/block/idea/idea.cpp
+++ b/src/block/idea/idea.cpp
@@ -55,13 +55,13 @@ u16bit mul_inv(u16bit x)
    return (1 - t0);
    }
 
-}
-
-/*
-* IDEA Encryption
+/**
+* IDEA is involutional, depending only on the key schedule
 */
-void IDEA::encrypt_n(const byte in[], byte out[], u32bit blocks) const
+void idea_op(const byte in[], byte out[], u32bit blocks, const u16bit K[52])
    {
+   const u32bit BLOCK_SIZE = 8;
+
    for(u32bit i = 0; i != blocks; ++i)
       {
       u16bit X1 = load_be<u16bit>(in, 0);
@@ -71,16 +71,16 @@ void IDEA::encrypt_n(const byte in[], byte out[], u32bit blocks) const
 
       for(u32bit j = 0; j != 8; ++j)
          {
-         X1 = mul(X1, EK[6*j+0]);
-         X2 += EK[6*j+1];
-         X3 += EK[6*j+2];
-         X4 = mul(X4, EK[6*j+3]);
+         X1 = mul(X1, K[6*j+0]);
+         X2 += K[6*j+1];
+         X3 += K[6*j+2];
+         X4 = mul(X4, K[6*j+3]);
 
          u16bit T0 = X3;
-         X3 = mul(X3 ^ X1, EK[6*j+4]);
+         X3 = mul(X3 ^ X1, K[6*j+4]);
 
          u16bit T1 = X2;
-         X2 = mul((X2 ^ X4) + X3, EK[6*j+5]);
+         X2 = mul((X2 ^ X4) + X3, K[6*j+5]);
          X3 += X2;
 
          X1 ^= X2;
@@ -89,10 +89,10 @@ void IDEA::encrypt_n(const byte in[], byte out[], u32bit blocks) const
          X3 ^= T1;
          }
 
-      X1  = mul(X1, EK[48]);
-      X2 += EK[50];
-      X3 += EK[49];
-      X4  = mul(X4, EK[51]);
+      X1  = mul(X1, K[48]);
+      X2 += K[50];
+      X3 += K[49];
+      X4  = mul(X4, K[51]);
 
       store_be(out, X1, X3, X2, X4);
 
@@ -101,48 +101,22 @@ void IDEA::encrypt_n(const byte in[], byte out[], u32bit blocks) const
       }
    }
 
+}
+
+/*
+* IDEA Encryption
+*/
+void IDEA::encrypt_n(const byte in[], byte out[], u32bit blocks) const
+   {
+   idea_op(in, out, blocks, EK);
+   }
+
 /*
 * IDEA Decryption
 */
 void IDEA::decrypt_n(const byte in[], byte out[], u32bit blocks) const
    {
-   for(u32bit i = 0; i != blocks; ++i)
-      {
-      u16bit X1 = load_be<u16bit>(in, 0);
-      u16bit X2 = load_be<u16bit>(in, 1);
-      u16bit X3 = load_be<u16bit>(in, 2);
-      u16bit X4 = load_be<u16bit>(in, 3);
-
-      for(u32bit j = 0; j != 8; ++j)
-         {
-         X1 = mul(X1, DK[6*j+0]);
-         X2 += DK[6*j+1];
-         X3 += DK[6*j+2];
-         X4 = mul(X4, DK[6*j+3]);
-
-         u16bit T0 = X3;
-         X3 = mul(X3 ^ X1, DK[6*j+4]);
-
-         u16bit T1 = X2;
-         X2 = mul((X2 ^ X4) + X3, DK[6*j+5]);
-         X3 += X2;
-
-         X1 ^= X2;
-         X4 ^= X3;
-         X2 ^= T0;
-         X3 ^= T1;
-         }
-
-      X1  = mul(X1, DK[48]);
-      X2 += DK[50];
-      X3 += DK[49];
-      X4  = mul(X4, DK[51]);
-
-      store_be(out, X1, X3, X2, X4);
-
-      in += BLOCK_SIZE;
-      out += BLOCK_SIZE;
-      }
+   idea_op(in, out, blocks, DK);
    }
 
 /*