Internet giants such as Google, Facebook and Twitter are working with a UK charity to help uncover and remove millions of online images of child sexual abuse.
Internet Watch Foundation (IWF), an anti-abuse organisation, is sharing lists of images of indecent abuse with web companies to protect their customers and help victims.
Sharing the lists - in which images are identified by a hash, or unique digital fingerprint - will allow victims' images to be identified and removed more quickly from the internet, preventing them from being repeatedly shared.
Establishment of the "hash list" is an escalation of the efforts to make the internet a hostile place to view, download and trade images of children being sexually abused, the IWF believes.
Chief executive Susie Hargreaves said the move could be a "game-changer" in the fight against the prevalence of child sexual abuse images.
The NSPCC welcomed the online industry taking a "more pro-active role" but warned there was more to be done to "strangle the life out of this sordid trade".
The move will help prevent images of abuse from being uploaded to the internet in the first place, giving companies the power to stop people from sharing images on their services.
It will also protect people from accidentally stumbling across the images online.
Creating a hash of a single image allows it to be "plucked" from the internet, akin to finding a needle in a haystack, the IWF said.
Lists will be shared with internet companies that provide services such as the uploading, storage or search of images, filtering or hosting services and social media and chat services, as well as those working in connectivity and data centres.
Hashes will be created from images that IWF analysts have assessed, regardless of whether they was sourced from a public report, a report from the online industry, an image actively found by the charity's analysts, or an image from the Home Office's new Child Abuse Image Database.
Ms Hargreaves said: "The IWF Hash List could be a game-changer and really steps up the fight against child sexual abuse images online.
"This is something we have worked on with our members since the Prime Ministers' #WePROTECT summit last December. We'll soon be able to offer the hash list to all IWF members, who are based around the world.
"It means victims' images can be identified and removed more quickly, and we can prevent known child sexual abuse images from being uploaded to the internet in the first place."
An NSPCC spokesman said: "This latest development will help tighten the grip on the source of child abuse images but there is still a way to go before we can strangle the life out of this sordid trade.
"This technological breakthrough is really positive and should enable the industry to take a far more pro-active role in blocking these horrendous pictures.
"However we mustn't forget the victims who may need protection from further abuse. Greater efforts have to be made to arrest those responsible for these abhorrent crimes. Until we have a unified approach to this problem it will continue to plague our communities."