As reported by BBC News, digital fingerprints of a million images of child sexual abuse have been created, the Internet Watch Foundation has said.
The UK charity, which is responsible for finding and removing such material online, said the fingerprints, known as hashes, would help companies and police find copies of the images. It is hoped that by doing this, the reuse of the images can be prevented. The images are from the government’s Child Abuse Image Database.
Creating a hash value of images helps tremendously when law enforcement quickly search for known child abuse images but circumvention is still very possible with little or no expertise by those wanting to avoid being caught. Technology is getting better at speeding up the process whilst attempting to catch those using evasion techniques but unfortunately this is a cat and mouse race where criminals are often far out in front.
Simply changing a single pixel in a known image can affect the hash value completely, which throws off the database. Technology is slowly catching up at spotting these affected images but the false positive rate makes this process timely and often requires human eyes to review, making it a difficult task.