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Crypto: New ChaCha20 wrapper around ChaChaCore, for use with Encrypted LS2

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This commit is contained in:
zzz
2019-02-19 19:11:34 +00:00
parent 14ac8fe545
commit e34b646231
3 changed files with 182 additions and 41 deletions
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43
router/java/src/com/southernstorm/noise/protocol/ChaChaPolyCipherState.java
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@ -89,45 +89,6 @@ public class ChaChaPolyCipherState implements CipherState {
public boolean hasKey() {
return haskey;
}
/**
* XOR's the output of ChaCha20 with a byte buffer.
*
* @param input The input byte buffer.
* @param inputOffset The offset of the first input byte.
* @param output The output byte buffer (can be the same as the input).
* @param outputOffset The offset of the first output byte.
* @param length The number of bytes to XOR between 1 and 64.
* @param block The ChaCha20 output block.
*/
private static void xorBlock(byte[] input, int inputOffset, byte[] output, int outputOffset, int length, int[] block)
{
int posn = 0;
int value;
while (length >= 4) {
value = block[posn++];
output[outputOffset] = (byte)(input[inputOffset] ^ value);
output[outputOffset + 1] = (byte)(input[inputOffset + 1] ^ (value >> 8));
output[outputOffset + 2] = (byte)(input[inputOffset + 2] ^ (value >> 16));
output[outputOffset + 3] = (byte)(input[inputOffset + 3] ^ (value >> 24));
inputOffset += 4;
outputOffset += 4;
length -= 4;
}
if (length == 3) {
value = block[posn];
output[outputOffset] = (byte)(input[inputOffset] ^ value);
output[outputOffset + 1] = (byte)(input[inputOffset + 1] ^ (value >> 8));
output[outputOffset + 2] = (byte)(input[inputOffset + 2] ^ (value >> 16));
} else if (length == 2) {
value = block[posn];
output[outputOffset] = (byte)(input[inputOffset] ^ value);
output[outputOffset + 1] = (byte)(input[inputOffset + 1] ^ (value >> 8));
} else if (length == 1) {
value = block[posn];
output[outputOffset] = (byte)(input[inputOffset] ^ value);
}
}
/**
* Set up to encrypt or decrypt the next packet.
@ -141,7 +102,7 @@ public class ChaChaPolyCipherState implements CipherState {
ChaChaCore.initIV(input, n++);
ChaChaCore.hash(output, input);
Arrays.fill(polyKey, (byte)0);
xorBlock(polyKey, 0, polyKey, 0, 32, output);
ChaChaCore.xorBlock(polyKey, 0, polyKey, 0, 32, output);
poly.reset(polyKey, 0);
if (ad != null) {
poly.update(ad, 0, ad.length);
@ -201,7 +162,7 @@ public class ChaChaPolyCipherState implements CipherState {
if (tempLen > length)
tempLen = length;
ChaChaCore.hash(output, input);
xorBlock(plaintext, plaintextOffset, ciphertext, ciphertextOffset, tempLen, output);
ChaChaCore.xorBlock(plaintext, plaintextOffset, ciphertext, ciphertextOffset, tempLen, output);
if (++(input[12]) == 0)
++(input[13]);
plaintextOffset += tempLen;