I ended up figuring this out by doing it within Bitcoin Core itself, instead of the OS X Terminal.

These are the 3 steps I took:

1. I pulled down from the "Help" menu to "Debug Window", then clicked on the "Console" tab.

2. I typed in: to unlock my wallet for 300 seconds.

3. I typed in: to increase the size of my keypool to 10000 addresses. It took a few minutes for it to complete the process.

Afterwards, to verify:
- I checked the size of my wallet.dat file in the OS X Finder, which had now increased to 4.4 MB.
- In Bitcoin Core's Debug Window, I typed in: which confirmed my keypool size as 10001 addresses. (Where does it get that extra 1 address from, I wonder?)

Thanks for everyone's help!

Thanks for the link. I was actually looking to work with the "Master Public Key" feature of Electrum HD, so that all the generated addresses would appear within Electrum.

Hi there,

I am interesting in building a database app that will allow a user to paste in their Master Public Key from their Electrum HD wallet, and then the database will generate public Bitcoin addresses for them (based on their Master Public Key).

Does anybody know where I can find instructions on how to generate public Bitcoin addresses from an Electrum HD Master Public Key?

Thanks!

Thank you for your replies!! And thank you for all the amazing work you guys do!!!

Thanks so much! That makes a lot of sense. Two questions:

1. Do you have any suggestions for where to store our old non-HD-generated private keys that were generated in Bitcoin Core for public addresses that are still posted publicly (such as within our YouTube videos)? These private keys will still be valuable to us for a long time into the future. Should we just export to a paper wallet?

2. Someone asked me the other day, "How can MultiBit HD be trusted if it isn't open source?" I was under the impression that MultiBit HD was open source, but it seems like I was incorrect about this?

Thanks!

Any chance that MultiBit HD will allow us to import private keys in the future, knowing that we would need to manually backup those keys? For example, Armory allows us to use both a seed and gives us the ability to import private keys as well.

Really great Bitcoin 101 speech:

http://youtu.be/EzFOwFXlR48

More women in Bitcoin! 

https://www.youtube.com/watch?v=Ct8uBO6ir3M

Thanks so much for the information. What sort of hoops does Apple require in order to sign software? Bitcoin Core is signed, so those developers have already jumped through the hoops on their end.

We'd love to install Armory for OS X, but we don't install apps that come from unidentified developers! Below is a link to the screenshot of the error message we get when trying to install Armory for OS X.

http://imgur.com/PII1Js2

Whoa. This is very useful information. Thanks so much, everybody!

Thanks so much, everyone, for the excellent advice! I didn't realize that a random number generator isn't the exact same thing as a cryptographically secure random number generator?? So the random number generator within database applications isn't truly random?

Please excuse the very beginner level technical question here, but is there a way to create a Bitcoin private key with a simple consumer database app such as FileMaker Pro or Microsoft Access?

My guess is that there IS such a way, since both database apps include a "random number generator" function.

I suppose I just don't know where to find the information on:
1. What SPECIFIC criteria makes up a valid private key, including the checksum at the end of the key?
2. Once I have generated the private key, how do I translate that into the public key to distribute publicly to others?

My goal is to have my company's internal invoicing system (which prints out invoices on old-fashioned paper) automatically generate a brand new Bitcoin address (public key) on each printed invoice, so that clients can have the option of paying their invoices with Bitcoin.

Thanks in advance for any help or guidance that you can provide!

Oh wait, I just read this paragraph from https://en.bitcoin.it/wiki/Wallet_encryption

"When a wallet is encrypted, the passphrase is required to top up the keypool, thus, if the passphrase is rarely entered, it is possible that keypool might run out. In this case, the default key will be used as the target for payouts for mining, and calls to getnewaddress and getaccount address will return an error. In order to prevent such cases, the keypool is automatically refilled when walletpassphrase is called with a correct passphrase and when topupkeypool is called (while the wallet is unlocked). Note that the keypool continues to be topped up on various occasions when a new key from pool is used and the wallet is unlocked (or unencrypted)."

Okay, that seems like what is happening to me. My wallet is encrypted, but I rarely use my passphrase because I am just receiving Bitcoins at this point. So I suppose that I won't be able to really see what's going on until I enter my passphrase. I suppose that this is all the more reason to switch to a HD wallet!  

Thanks so much for your guidance. I ran the "getwalletinfo" command, and sure enough, my keypool size never increased yesterday when I ran the OS X Terminal command "bitcoin-qt -keypool=1000". No idea why it didn't work, but the "getwalletinfo" command confirmed to me that my keypoolsize was still at 101.

Then, I downloaded your sample configuration file -- thank you so much for creating this! I uncommented the keypool line and increased the number to 1000. I quit Bitcoin-QT, put the config file in the proper location (with the proper filename), and relaunched Bitcoin-QT. I created 4 new Receiving Addresses, then checked my keypoolsize with the "getwalletinfo" command, and it had not increased to 1000.  Instead, it simply told me that my keypool size is 97, which was the number of new addresses deducted from the former keypool size of 101.

So I quit Bitcoin-QT, deleted the config file altogether, relaunched Bitcoin-QT, created 2 new receiving addresses, but now my keypool size number is down to 95. It's not refilling my keypool automatically! Isn't Bitcoin-QT always supposed to refill the keypool, and keep this number at 100 or 101? Now I'm losing my keypool altogether, and I don't think I did anything wrong. But now it seems like I don't have a keypool at all.

Oh well, I'm clearly going to have to stop experimenting with all of this now. This is clearly waaay over my head, I can't figure it out, and I'm too nervous about making some change that is going to cause me to inadvertently lose my Bitcoins. It seems like I'm already on some path to destruction, because my keypool is no longer automatically refilling itself. So I'm going to stop now, and just make sure that I make backups every day. Now I don't have a auto-refilling keypool at all. Very sad.  I wonder what will happen when it gets to 0?

Thanks. Hmmm... I guess there's no way for me to tell what the size of my keypool is at the current moment. In the Finder, my wallet.dat file is the same size today that it was last week, so I'm assuming that my keypool never increased in size.  

Thanks. Nope, typing that in just yielded an empty line as the result.

Actually, I should say that I THINK it worked. Is there any way for me to tell if I now have 1,000 addresses in my Bitcoin-QT keypool? Is there a different terminal command that I can run, which will list all the public addresses in my keypool??    If I see a list of 1,000 addresses, then I know for sure that it worked!

Ah, thanks so much!!! That worked, once I removed the period at the beginning of the path.

So, to summarize, I quit out of Bitcoin-Qt, then I launched OS X Terminal and typed:

/Applications/Bitcoin-Qt.app/Contents/MacOS/Bitcoin-Qt -keypool=1000

And that did the trick!! Thank you so much!!

Thanks, I went into the OS X Terminal and typed in

bitcoin-qt -keypool=1000

but it returned the error message "command not found".

I don't feel comfortable creating & editing a config file. Would love to be able to just use the terminal command, but there seems to be no instructions anywhere on how to actually use these terminal commands.

(LOL. And we wonder why "normal people" don't use Bitcoin yet. This is so many years away from being easy enough for the mainstream populace! )