I need to compare an email list with a list curated by someone else and see the % of overlap.
The first thought is to make hashes out of each email. However this only works until a match is found. Once we have overlap we will both know who is a double-subscriber, and this is arguably confidential info.
Any idea how to do this.
Is there any service that would allow us to compare? I am thinking that the matches would be meaningless for that 3rd party.