$BTC oin [20], the world’s first successful crypto-currency, is increasingly becom-

ing a popular method of payment for e-commerce due to low transaction fees

and the ease of use supplied by third party Payment Processors. BitPay and

Coinbase are currently the two dominant Payment Processors that handle Bit-

coin payments for more than 100,000 merchants. Their customers include Dell,

Microsoft, Overstock, Shopify, Paypal and CeX. This demonstrates that large

organisations are placing trust in Bitcoin as a viable form of payment. In fact,

Overstock claimed to have made $3 million worth of Bitcoin sales in 2014 [12].

These Payment Processors are attractive due to their ability to convert bitcoins

into fiat currency instantly which removes the risk involved in Bitcoin’s price

volatility on behalf of the merchant.

Both Payment Processors and all merchants are recommended to follow the

community accepted BIP70: Payment Protocol standard that was proposed by

Andresen and Hearn [5] to be used with Bitcoin. The motivation for this proto-

col is to reduce the complexity of Bitcoin payments as customers are no longer

required to handle Bitcoin addresses1. Instead, the customer can verify the mer-

chant’s identity using a human-readable name before authorising a payment.

1A form of identity (26–35 alphanumeric characters) that is related to a public-private

key pair and is used to send/receive bitcoin