private byte[] shaBlock(int length = PSVIMGConstants.PSVIMG_BLOCK_SIZE, bool final = false)
{
byte[] outbytes = new byte[PSVIMGConstants.SHA256_BLOCK_SIZE];
shaCtx.BlockUpdate(blockData, 0x00, length);
Sha256Digest shaTmp = (Sha256Digest)shaCtx.Copy();
shaTmp.DoFinal(outbytes, 0x00);
return(outbytes);
}