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The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.8 and up.
package org.bouncycastle.pqc.crypto.rainbow;
import java.security.SecureRandom;
import org.bouncycastle.crypto.Digest;
import org.bouncycastle.util.Arrays;
/**
* This class is needed for the conversions while encoding and decoding, as well as for
* comparison between arrays of some dimensions
*/
class RainbowUtil
{
/**
* This function converts an one-dimensional array of bytes into a
* one-dimensional array of type short
*
* @param in the array to be converted
* @return out
* one-dimensional short-array that corresponds the input
*/
public static short[] convertArray(byte[] in)
{
short[] out = new short[in.length];
for (int i = 0; i < in.length; i++)
{
out[i] = (short)(in[i] & GF2Field.MASK);
}
return out;
}
/**
* This function converts an array of type short into an array of type byte
*
* @param in the array to be converted
* @return out
* the byte-array that corresponds the input
*/
public static byte[] convertArray(short[] in)
{
byte[] out = new byte[in.length];
for (int i = 0; i < in.length; i++)
{
out[i] = (byte)in[i];
}
return out;
}
/**
* Compare two short arrays. No null checks are performed.
*
* @param left the first short array
* @param right the second short array
* @return the result of the comparison
*/
public static boolean equals(short[] left, short[] right)
{
if (left.length != right.length)
{
return false;
}
boolean result = true;
for (int i = left.length - 1; i >= 0; i--)
{
result &= left[i] == right[i];
}
return result;
}
/**
* Compare two two-dimensional short arrays. No null checks are performed.
*
* @param left the first short array
* @param right the second short array
* @return the result of the comparison
*/
public static boolean equals(short[][] left, short[][] right)
{
if (left.length != right.length)
{
return false;
}
boolean result = true;
for (int i = left.length - 1; i >= 0; i--)
{
result &= equals(left[i], right[i]);
}
return result;
}
/**
* Compare two three-dimensional short arrays. No null checks are performed.
*
* @param left the first short array
* @param right the second short array
* @return the result of the comparison
*/
public static boolean equals(short[][][] left, short[][][] right)
{
if (left.length != right.length)
{
return false;
}
boolean result = true;
for (int i = left.length - 1; i >= 0; i--)
{
result &= equals(left[i], right[i]);
}
return result;
}
public static short[][] cloneArray(short[][] toCopy)
{
short[][] local = new short[toCopy.length][];
for (int i = 0; i < toCopy.length; i++)
{
local[i] = Arrays.clone(toCopy[i]);
}
return local;
}
public static short[][][] cloneArray(short[][][] toCopy)
{
short[][][] local = new short[toCopy.length][toCopy[0].length][];
for (int i = 0; i < toCopy.length; i++)
{
for (int j = 0; j < toCopy[0].length; j++)
{
local[i][j] = Arrays.clone(toCopy[i][j]);
}
}
return local;
}
public static byte[] hash(Digest hashAlgo, byte[] partA, byte[] partB, byte[] result)
{
int digest_size = hashAlgo.getDigestSize();
// final_hash = hash(msg) || hash(hash(msg)) || ...
byte[] final_hash;
// initial hash of msg
hashAlgo.update(partA, 0, partA.length);
hashAlgo.update(partB, 0, partB.length);
if (result.length == digest_size)
{
hashAlgo.doFinal(result, 0);
return result;
}
byte[] hash = new byte[digest_size];
hashAlgo.doFinal(hash, 0);
// check if truncation is needed
if (result.length < digest_size)
{
System.arraycopy(hash, 0, result, 0, result.length);
return result;
}
System.arraycopy(hash, 0, result, 0, hash.length);
// compute expansion while needed
int left_to_hash = result.length - digest_size;
int index = digest_size;
while (left_to_hash >= hash.length)
{
hashAlgo.update(hash, 0, hash.length);
hashAlgo.doFinal(hash, 0);
System.arraycopy(hash, 0, result, index, hash.length);
left_to_hash -= hash.length;
index += hash.length;
}
// check if final expansion is needed
if (left_to_hash > 0)
{
hashAlgo.update(hash, 0, hash.length);
hashAlgo.doFinal(hash, 0);
System.arraycopy(hash, 0, result, index, left_to_hash);
}
return result;
}
public static byte[] hash(Digest hashAlgo, byte[] msg, int hash_length)
{
int digest_size = hashAlgo.getDigestSize();
// final_hash = hash(msg) || hash(hash(msg)) || ...
byte[] final_hash;
// initial hash of msg
hashAlgo.update(msg, 0, msg.length);
byte[] hash = new byte[digest_size];
hashAlgo.doFinal(hash, 0);
// check if truncation is needed
if (hash_length == digest_size)
{
return hash;
}
else if (hash_length < digest_size)
{
return Arrays.copyOf(hash, hash_length);
}
else
{
final_hash = Arrays.copyOf(hash, digest_size);
}
// compute expansion while needed
int left_to_hash = hash_length - digest_size;
while (left_to_hash >= digest_size)
{
hashAlgo.update(hash, 0, digest_size);
hash = new byte[digest_size];
hashAlgo.doFinal(hash, 0);
final_hash = Arrays.concatenate(final_hash, hash);
left_to_hash -= digest_size;
}
// check if final expansion is needed
if (left_to_hash > 0)
{
hashAlgo.update(hash, 0, digest_size);
hash = new byte[digest_size];
hashAlgo.doFinal(hash, 0);
int current_length = final_hash.length;
final_hash = Arrays.copyOf(final_hash, current_length + left_to_hash);
System.arraycopy(hash, 0, final_hash, current_length, left_to_hash);
}
return final_hash;
}
public static short[][] generate_random_2d(SecureRandom sr, int dim_row, int dim_col)
{
byte[] tmp = new byte[dim_row * dim_col];
sr.nextBytes(tmp);
short[][] matrix = new short[dim_row][dim_col];
for (int j = 0; j < dim_col; j++)
{
for (int i = 0; i < dim_row; i++)
{
matrix[i][j] = (short)((tmp[j * dim_row + i] & GF2Field.MASK));
}
}
return matrix;
}
public static short[][][] generate_random(SecureRandom sr, int dim_batch, int dim_row, int dim_col, boolean triangular)
{
int bytes_needed;
if (triangular)
{
bytes_needed = dim_batch * (dim_row * (dim_row + 1) / 2);
}
else
{
bytes_needed = dim_batch * dim_row * dim_col;
}
byte[] tmp = new byte[bytes_needed];
sr.nextBytes(tmp);
int index = 0;
short[][][] matrix = new short[dim_batch][dim_row][dim_col];
for (int i = 0; i < dim_row; i++)
{
for (int j = 0; j < dim_col; j++)
{
for (int k = 0; k < dim_batch; k++)
{
if (triangular && (i > j))
{
continue;
}
matrix[k][i][j] = (short)((tmp[index++] & GF2Field.MASK));
}
}
}
return matrix;
}
public static byte[] getEncoded(short[][] a)
{
int row = a.length;
int col = a[0].length;
byte[] ret = new byte[row * col];
for (int j = 0; j < col; j++)
{
for (int i = 0; i < row; i++)
{
ret[j * row + i] = (byte)a[i][j];
}
}
return ret;
}
public static byte[] getEncoded(short[][][] a, boolean triangular)
{
int dim = a.length;
int row = a[0].length;
int col = a[0][0].length;
int ret_size;
if (triangular)
{
ret_size = dim * (row * (row + 1) / 2);
}
else
{
ret_size = dim * row * col;
}
byte[] ret = new byte[ret_size];
int cnt = 0;
for (int i = 0; i < row; i++)
{
for (int j = 0; j < col; j++)
{
for (int k = 0; k < dim; k++)
{
if (triangular && (i > j))
{
continue;
}
ret[cnt] = (byte)a[k][i][j];
cnt++;
}
}
}
return ret;
}
public static int loadEncoded(short[][] a, byte[] enc, int off)
{
int row = a.length;
int col = a[0].length;
for (int j = 0; j < col; j++)
{
for (int i = 0; i < row; i++)
{
a[i][j] = (short)(enc[off + j * row + i] & 0xff);
}
}
return row * col;
}
public static int loadEncoded(short[][][] a, byte[] enc, int off, boolean triangular)
{
int dim = a.length;
int row = a[0].length;
int col = a[0][0].length;
int cnt = 0;
for (int i = 0; i < row; i++)
{
for (int j = 0; j < col; j++)
{
for (int k = 0; k < dim; k++)
{
if (triangular && (i > j))
{
continue;
}
a[k][i][j] = (short)(enc[off + cnt++] & 0xff);
}
}
}
return cnt;
}
}
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