diff options
Diffstat (limited to 'core/src/main/java/org/bouncycastle/crypto/modes/gcm/GCMUtil.java')
| -rw-r--r-- | core/src/main/java/org/bouncycastle/crypto/modes/gcm/GCMUtil.java | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/core/src/main/java/org/bouncycastle/crypto/modes/gcm/GCMUtil.java b/core/src/main/java/org/bouncycastle/crypto/modes/gcm/GCMUtil.java new file mode 100644 index 00000000..48753011 --- /dev/null +++ b/core/src/main/java/org/bouncycastle/crypto/modes/gcm/GCMUtil.java @@ -0,0 +1,260 @@ +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 byte[] asBytes(int[] ns) + { + byte[] output = new byte[16]; + Pack.intToBigEndian(ns, output, 0); + return output; + } + + static int[] asInts(byte[] bs) + { + int[] output = new int[4]; + Pack.bigEndianToInt(bs, 0, output); + return output; + } + + static void asInts(byte[] bs, int[] output) + { + Pack.bigEndianToInt(bs, 0, output); + } + + 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 multiplyP(int[] x, int[] output) + { + boolean lsb = (x[3] & 1) != 0; + shiftRight(x, output); + if (lsb) + { + output[0] ^= 0xe1000000; + } + } + + // P is the value with only bit i=1 set + 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 multiplyP8(int[] x, int[] output) + { + int lsw = x[3]; + shiftRightN(x, 8, output); + for (int i = 7; i >= 0; --i) + { + if ((lsw & (1 << i)) != 0) + { + output[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(byte[] block, byte[] output) + { + int i = 0; + int bit = 0; + for (;;) + { + int b = block[i] & 0xff; + output[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 shiftRight(int[] block, int[] output) + { + int i = 0; + int bit = 0; + for (;;) + { + int b = block[i]; + output[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 shiftRightN(int[] block, int n, int[] output) + { + int i = 0; + int bits = 0; + for (;;) + { + int b = block[i]; + output[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(byte[] block, byte[] val, int off, int len) + { + while (len-- > 0) + { + block[len] ^= val[off + len]; + } + } + + static void xor(byte[] block, byte[] val, byte[] output) + { + for (int i = 15; i >= 0; --i) + { + output[i] = (byte)(block[i] ^ val[i]); + } + } + + static void xor(int[] block, int[] val) + { + for (int i = 3; i >= 0; --i) + { + block[i] ^= val[i]; + } + } + + static void xor(int[] block, int[] val, int[] output) + { + for (int i = 3; i >= 0; --i) + { + output[i] = block[i] ^ val[i]; + } + } +} |