The world of gold bullion sales is often peopled by the odd and interesting. Joseph Castillo is one of the latter. The owner of Agora Commodities, his company now only accepts Bitcoin for online sales, a move that has reduced fraud and improved his service.

Castillo talked to Coindesk about his decision, saying that “What we had to do to protect ourselves against card fraud, we no longer have to do with bitcoin – and that saves us on costs.”

The company has done $10 million in revenue through bitcoin since he moved to cryptocurrencies in the beginning of 2014. Customers understood the move and have been working with him to transfer assets via the blockchain rather than the Visa card. Castillo is also planning on building a BTC exchange for his customers. The goal is to create a one-stop-shop for all your goldbug tendencies, including fiat to BTC conversions.

“Bitcoin fits perfectly with gold and silver, right? So if people come to the site and want to buy gold and silver, why wouldn’t they want to buy bitcoin from us as well?” he told Coindesk.

Seems like Bitcoin (and other) mining is artificially crippled so the miner devs make higher profits:
http://da-data.blogspot.de/2014/08/minting-money-with-monero-and-cpu.html

EBay’s PayPal Unit to Start Accepting Bitcoin Payments

EBay Inc. (EBAY)’s PayPal service will start accepting bitcoins, opening up the world’s second-biggest Internet payment network to virtual currency transactions.

“We’re announcing PayPal’s first foray into bitcoin,” Bill Ready, the chief of EBay’s Braintree unit, said at Techcrunch’s Disrupt SF conference yesterday. “Over the coming months we’ll allow our merchants to accept bitcoin. On the consumer side it will be a sleek experience.”

EBay, as the world’s biggest Web marketplace and operator of a global payments service, is the most significant business to date that’s embraced bitcoin. The move could potentially enable PayPal’s 152 million registered accounts to transact using the virtual currency, spurring wider use and acceptance of bitcoin, according to Gil Luria, an analyst at Wedbush Securities Inc.

“PayPal integrating bitcoin into Braintree is a very substantial development,” Luria said. “Not only will it make it possible for some of the fastest-growing apps to integrate bitcoin seamlessly, it opens the door for PayPal to integrate bitcoin into its main wallet functionality. If that happens millions of retailers will de facto be accepting bitcoin overnight.”

The Math Behind Bitcoin

One reason Bitcoin can be confusing for beginners is that the technology behind it redefines the concept of ownership.

To own something in the traditional sense, be it a house or a sum of money, means either having personal custody of the thing or granting custody to a trusted entity such as a bank.

With Bitcoin the case is different. Bitcoins themselves are not stored either centrally or locally and so no one entity is their custodian. They exist as records on a distributed ledger called the block chain, copies of which are shared by a volunteer network of connected computers. To “own” a bitcoin simply means having the ability to transfer control of it to someone else by creating a record of the transfer in the block chain. What grants this ability? Access to an ECDSA private and public key pair. What does that mean and how does that secure Bitcoin?

Let’s have a look under the hood.

...SNIP...

Conclusion

For those of you who saw all the equations and skipped to the bottom, what have we just learned?

We have developed some intuition about the deep mathematical relationship that exists between public and private keys. We have seen how even in the simplest examples the math behind signatures and verification quickly gets complicated, and we can appreciate the enormous complexity which must be involved when the parameters involved are 256-bit numbers. We have seen how the clever application of the simplest mathematical procedures can create the one-way “trap door” functions necessary to preserve the information asymmetry which defines ownership of a bitcoin. And we have newfound confidence in the robustness of the system, provided that we carefully safeguard the knowledge of our private keys.

In other words, this is why it is commonly said that Bitcoin is “backed by math.”

If you hung in through the complicated bits, we hope it gave you the confidence to take the next step and try out the math on your own (a modular arithmetic calculator makes the finite field math much easier). We found that going through the steps of signing and verifying data by hand provides a deeper understanding of the cryptography that enables Bitcoin’s unique form of ownership.

I decided to give out $0.10 USD worth of Bitcoin to anybody who uses ktbyte.com:

• (Optional) Try our free intro CS class on a desktop / laptop
• Make an account and login
• Click the check button after listening to any lecture (or solve a problem). The shortest lecture is the intro. Should take you less than 10 seconds.
• Go to https://www.ktbyte.com/users/progress#freegoodie and send me the redirected url (or paste it below), and I'll send you your bits using changetip!

The second two steps are there so that we don't get ddosed by bots.