BlockCypher: Zero Confirmation Bitcoin Transactions Still Viable – CCN …


BlockCypher provides Bitcoin wallet services to larger organizations such as exchanges and payment providers. During the recent fracas of “dust” transactions crowding the Bitcoin network, one of their larger clients, Erik Voorhees’, suffered a double-spend attack amounting to 2.6 BTC.

The biggest offering of BlockCypher is what they call a “Confidence Factor” which basically means what it sounds like – if the processor is reasonably sure (as in more than 99%) that a double-spend will not be attempted, the transaction is processed with zero confirmations. BlockCypher describes their method like so:

In simpler terms, if an unconfirmed transaction returns a confidence factor of 99.9%, then our data says there’s a 0.1% chance that an attempted double-spend will succeed. By design, we’re conservative. Even when we return 90% confidence, the likelihood of a successful double-spend is significantly lower than 10%.

The ability to do fast transactions is crucial to a business like ShapeShift, which offers instant conversions between cryptocurrencies. The technology is useful to Bitnet, the payment processor that has made several strategic partnerships in the last few months, not the least of which was with Cardinal Commerce, one of the bigger payment providers on the globe. Their ability to process transactions quickly and seamlessly is critical to their business model, and so it is no surprise that they have integrated BlockCypher’s Confidence Factor as well.

More Than 100,000 Double-Spend Attempts

Although vague as to how it occurred, a representative of BlockCypher, Josh Cincinnati, has published an insightful blog explaining that the attack vector used to execute the double-spend has

Originally appeared at: