Nick Szabo’s writing connects questions about trust, property, computation, and money. Two primary texts are especially useful here: Smart Contracts, dated 1994, and Bit Gold, published in December 2005. Read Smart Contracts and Bit Gold.
Agreements expressed in software
In Smart Contracts, Szabo describes computerized transaction protocols that execute contractual terms. He considers reducing reliance on intermediaries, but also asks whether software makes its actions understandable to the people using it. The idea predates Bitcoin and is broader than programs on a blockchain. The 1994 essay.
The bit gold proposal
The later essay describes proof-of-work results that are timestamped and entered into a distributed ownership registry. Each result supplies a challenge for the next. Szabo also discusses difficulties: hardware advantages and the challenge of making differently costly results interchangeable. The 2005 essay.
The text itself is careful about unresolved questions. It should not be rewritten as a claim that every part of Bitcoin had already been implemented.
Date the evidence precisely
The 2005 essay says the idea came earlier, but that is not an exact conception date. This profile dates the published document rather than assigning an unsupported year to a private thought process.
Our interest is in the proposals readers can inspect. Speculation about whether Szabo is Satoshi does not help explain how bit gold’s mechanism differs from Bitcoin’s.