public bool VerifyContent(byte[] content, uint offset)
{
Throw.If(offset >= MaxDepthLeafCount, "Offset does not correspond to maximum depth leaf");
var hash = new Hash(CryptoExtensions.Sha256(content, 0, (uint)content.Length));
return(hash == _tree[offset]);
}
// chunkSize must be a power of 2
public MerkleTree(byte[] content)
{
//Throw.If(content == null || content.Length < ChunkSize, "invalid content");
Throw.If(content == null, "invalid content");
var chunkCount = (uint)(content.Length / ChunkSize);
if (chunkCount * ChunkSize < content.Length)
{
chunkCount++;
}
MaxDepthLeafCount = NextPowerOf2(chunkCount);
//int maxLevel = 1;
var temp = MaxDepthLeafCount;
uint nodeCount = 0;
while (temp > 0)
{
nodeCount += temp;
temp /= 2;
//maxLevel++;
}
_tree = new Hash[nodeCount];
//hash the maximum depth leaves of the tree
for (int i = 0; i < MaxDepthLeafCount; i++)
{
Hash hash;
var ofs = (uint)(i * ChunkSize);
if (ofs < content.Length)
{
var length = ChunkSize;
if (ofs + length > content.Length)
{
length = (uint)(content.Length - ofs);
}
hash = new Hash(CryptoExtensions.Sha256(content, ofs, length));
}
else
{
hash = Hash.Null;
}
_tree[i] = hash;
}
//and how combine the leaf hashes in the branches
uint prevOffset = 0;
uint prevRows = MaxDepthLeafCount;
while (true)
{
uint rows = prevRows / 2;
if (rows <= 0)
{
break;
}
uint offset = prevOffset + prevRows;
for (uint i = 0; i < rows; i++)
{
uint childIndex = prevOffset + (i * 2);
var left = _tree[childIndex];
var right = _tree[childIndex + 1];
_tree[offset + i] = Hash.MerkleCombine(left, right);
}
prevOffset = offset;
prevRows = rows;
}
}
public static Hash CalculateBlockHash(byte[] content)
{
var hash = new Hash(CryptoExtensions.Sha256(content, 0, (uint)content.Length));
return(hash);
}
public static Hash FromString(string str)
{
var bytes = CryptoExtensions.Sha256(str);
return(new Hash(bytes));
}