A Cloud-User Protocol Based on Ciphertext Watermarking Technology

Algorithm 2

Generating .

Input: SW(Set of exist watermark of U with same

Fea), , L(Capacity of File)

Output: A new watermark

  while  flag  do

   randomly generate a sequence t shorter than . for

All item in SW  do

  if  sumthen

   break

  end

  end

  end

  return