1 files changed, 155 insertions, 0 deletions
diff --git a/bcprov/src/main/java/org/bouncycastle/crypto/modes/gcm/GCMUtil.java b/bcprov/src/main/java/org/bouncycastle/crypto/modes/gcm/GCMUtil.java
new file mode 100644
index 0000000..ce02be4
--- /dev/null
+++ b/bcprov/src/main/java/org/bouncycastle/crypto/modes/gcm/GCMUtil.java
@@ -0,0 +1,155 @@
+package org.bouncycastle.crypto.modes.gcm;
+
+import org.bouncycastle.crypto.util.Pack;
+import org.bouncycastle.util.Arrays;
+
+abstract class GCMUtil
+{
+    static byte[] oneAsBytes()
+    {
+        byte[] tmp = new byte[16];
+        tmp[0] = (byte)0x80;
+        return tmp;
+    }
+
+    static int[] oneAsInts()
+    {
+        int[] tmp = new int[4];
+        tmp[0] = 0x80000000;
+        return tmp;
+    }
+
+    static int[] asInts(byte[] bs)
+    {
+        int[] us = new int[4];
+        us[0] = Pack.bigEndianToInt(bs, 0);
+        us[1] = Pack.bigEndianToInt(bs, 4);
+        us[2] = Pack.bigEndianToInt(bs, 8);
+        us[3] = Pack.bigEndianToInt(bs, 12);
+        return us;
+    }
+
+    static void multiply(byte[] block, byte[] val)
+    {
+        byte[] tmp = Arrays.clone(block);
+        byte[] c = new byte[16];
+
+        for (int i = 0; i < 16; ++i)
+        {
+            byte bits = val[i];
+            for (int j = 7; j >= 0; --j)
+            {
+                if ((bits & (1 << j)) != 0)
+                {
+                    xor(c, tmp);
+                }
+
+                boolean lsb = (tmp[15] & 1) != 0;
+                shiftRight(tmp);
+                if (lsb)
+                {
+                    // R = new byte[]{ 0xe1, ... };
+//                    GCMUtil.xor(v, R);
+                    tmp[0] ^= (byte)0xe1;
+                }
+            }
+        }
+
+        System.arraycopy(c, 0, block, 0, 16);
+    }
+
+    // P is the value with only bit i=1 set
+    static void multiplyP(int[] x)
+    {
+        boolean lsb = (x[3] & 1) != 0;
+        shiftRight(x);
+        if (lsb)
+        {
+            // R = new int[]{ 0xe1000000, 0, 0, 0 };
+//            xor(v, R);
+            x[0] ^= 0xe1000000;
+        }
+    }
+
+    static void multiplyP8(int[] x)
+    {
+//        for (int i = 8; i != 0; --i)
+//        {
+//            multiplyP(x);
+//        }
+
+        int lsw = x[3];
+        shiftRightN(x, 8);
+        for (int i = 7; i >= 0; --i)
+        {
+            if ((lsw & (1 << i)) != 0)
+            {
+                x[0] ^= (0xe1000000 >>> (7 - i));
+            }
+        }
+    }
+
+    static void shiftRight(byte[] block)
+    {
+        int i = 0;
+        int bit = 0;
+        for (;;)
+        {
+            int b = block[i] & 0xff;
+            block[i] = (byte) ((b >>> 1) | bit);
+            if (++i == 16)
+            {
+                break;
+            }
+            bit = (b & 1) << 7;
+        }
+    }
+
+    static void shiftRight(int[] block)
+    {
+        int i = 0;
+        int bit = 0;
+        for (;;)
+        {
+            int b = block[i];
+            block[i] = (b >>> 1) | bit;
+            if (++i == 4)
+            {
+                break;
+            }
+            bit = b << 31;
+        }
+    }
+
+    static void shiftRightN(int[] block, int n)
+    {
+        int i = 0;
+        int bits = 0;
+        for (;;)
+        {
+            int b = block[i];
+            block[i] = (b >>> n) | bits;
+            if (++i == 4)
+            {
+                break;
+            }
+            bits = b << (32 - n);
+        }
+    }
+
+    static void xor(byte[] block, byte[] val)
+    {
+        for (int i = 15; i >= 0; --i)
+        {
+            block[i] ^= val[i];
+        }
+    }
+
+    static void xor(int[] block, int[] val)
+    {
+        for (int i = 3; i >= 0; --i)
+        {
+            block[i] ^= val[i];
+        }
+    }
+}