Image: Surety.com
Before Satoshi and Bitcoin, researchers Stuart Haber and Scott Stornetta invented the blockchain concept in a paper published in the Journal of Cryptography in 1991. They then went on to found a company called Surety which provided timestamping and digital seal services for digital documents. To satisfy the public ledger aspect of their blcokchain implementation, they published a hash of all their clients seals in the Lost and Found section of The New York Times once a week since 1995.
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