This was a development by David Chaum put out in 1983. It was the first known attempt at digital, decentralized money. He set up a corporation Digicash and used the software as a micropayment processor at one US bank during 1995-1998.
He first put his paper out in 1983. Digicash was set up in 1989.
Mark Twain bank was the only one to try it in the United States. The money was stores on a local computer in a digital format, cryptographically signed by a bank. One simply could send the money to any store accepting eCash.
The business model was similar to credit cards in that it was free to users and the merchants were the ones charged. One of the issues for the company was the timing because credit card usage took off in the late 1990s. Visa credit and debit cards really took off.
After the trial with Mark Twain bank ended, Digicash went bankrupt.
It is believed that eCash was one of the templates that was used for the formation of the Bitcoin network. Blockchain mechanics are similar to what the early Cypherpunks were playing around with.
We can see the fingerprints of the early pioneers all throughout the cryptocurrency industry.