Mycelium Bitcoin Wallet

[PremiumCodeX]

It seems the transaction fees increased ouse to be able to send for only a two cent fee now it's 14. I am only testing 100k Satoshi. Are they cheaper fees when I send more?

The transaction fee will depend on the size of the transmission in terms of kB.
If you have many small output in your wallet, then will you fee increase.
You can set mycelium for different priorities, high priority calculates a higher fee, but will also get confirmed faster.  

I am interested, but I am not using this wallet yet and I wonder if I have to look through a lot of code to find the answer.
How can I determine the size of the transmission for a certain amount of BTC sending or receiveing transaction in this wallet?

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[HCP]

It doesn't show the exact size... but you can roughly calculate it using the standard formula:

the size of the tx will be: 180 bytes per input + 34 bytes per output + 10 bytes.

For determining how many inputs you are going to have... From what I have seen, it would appear that Mycelium tries to be smart and optimises the transaction size by using the most appropriately sized, oldest, unspent input(s)...  if that is what you are asking?

For example... if your current wallet inputs are (in order from oldest to newest):

1. 0.01
2. 0.0043
3. 0.02
4. 0.1
5. 0.05

and you wanted to send 0.04BTC... it would use 5... which would *should* theoretically keep the transaction size (and fees required) as small as possible...

NOTE: I am not 100% sure that this is how it works... as I haven't checked the code either... but a quick look at my sends, seems to indicate that it is picking up the "best fit" unspent inputs to cover the outgoing amount.

[trasla]

Mycelium starts with the oldest output and adds more until enough value for the transaction was added, then goes through the outputs and checks whether some can get removed again.

If you have outputs, in chronological order, of
5, 5, 1, 5, 1, 20
If you want to send 12, it will select the first 4 ones, then remove the third one, so end up with the first, second and forth. If you want to send 18 it will select all, then remove all but the last one.

So it tries to spend older outputs over newer ones but optimizes to not include unnecessary outputs. A potential feature for some distant future which was discussed would be to have different options for output selection to pick from.

[HCP]

Ahhhh ok... That makes sense.

I went through my history, and was trying to track down how it was choosing the unspent inputs... At first I thought it was just using the oldest, regardless of optimisation... but then I noted that it had "skipped" a couple... so I figured it was trying to be clever. Just wasn't sure of the exact methodology and I was too lazy to read the source today (had a property inspection so was busy cleaning  )

Thanks for the clarification.

[PremiumCodeX]

It doesn't show the exact size... but you can roughly calculate it using the standard formula:

the size of the tx will be: 180 bytes per input + 34 bytes per output + 10 bytes.

That was what I was asking and I appreciate your will you tried to help me first!  I understand the calculation you wrote is a rough calculation that provides an estimated result for the tx, but it may be different in real because Mycelium tries to optimize the transaction. Well, even an estimated result is better than having no idea so I thank you!

Mycelium starts with the oldest output and adds more until enough value for the transaction was added, then goes through the outputs and checks whether some can get removed again.

...and if you wanted to send 16, it would choose the first four ones then remove nothing because 5 + 5 + 1 + 5 is 16 exactly. I hope I understand right, thank you! I could appreciate a feature to select my output option and also information about the exact fee before transaction, though.

[hgmichna]

… information about the exact fee before transaction …

Keep in mind that the ultimate effect of the fee amount, the speed of confirmation, is fundamentally very inexact. It may not be worth the trouble to aim for exactness here.

I think though that Mycelium displays the exact fee and changes it when you change the priority level.

[dooglus]

There will not be much development going on for the current app, efforts are focused on the new shiny next generation

Some feature requests for the next generation:

1) Allow me access multiple receiving addresses so I can issue more than one invoice at a time

2) Offer some kind of proper wallet encryption feature. A 6 digit code just doesn't cut it. I want something like Bitcoin Core has, so that when my phone is stolen I know it will take the thief a significant amount of time to access my wallet seed. Currently I think all he needs to do is root the phone and my seed is there in plain text. That's a worry.

3) Allow me to use my own local bitcore server instead of a central Mycelium server for blockchain queries and transaction broadcast.

Have you taken a look at the new Breadwallet beta that is available for Android phones running Marshmallow 6.0? The fully encrypted phone and fingerprint verification used by the wallet looks like a pretty secure setup for moderate amounts of bitcoin. Breadwallet connects directly to the bitcoin network and stores secret keys in the phone's hardware encrypted keystore,

Yes I have.

1) breadwallet has the same shortcoming - you can only have one receiving address at a time

2) the PIN is only 4 digits, not 6, so it's worse in this respect

3) breadwallet connects to random full nodes; I cannot tell it which nodes to connect to

In addition, breadwallet shows my balance in 'b', which it defines as a millionth of a bitcoin. The developers refuse to allow us to see amounts in BTC. I'll be sticking with Mycelium for now, despite its shortcomings.

[dooglus]

So, with Mycelium BTC Wallet and a portable device that can run Android, can I create my own "hardware wallet"? I find it awesome.

Well, kind of. Usually when people talk about "hardware wallets" they mean some kind of device which can't be hacked due to the code it runs being very limited in scope, and uneditable without physically pressing some buttons on the device. Android on the other hand is a general purpose operating system and probably has many vulnerabilities and possibly even deliberate backdoors.

...and if you wanted to send 16, it would choose the first four ones then remove nothing because 5 + 5 + 1 + 5 is 16 exactly. I hope I understand right, thank you! I could appreciate a feature to select my output option and also information about the exact fee before transaction, though.

If the 16 included the fee, yes, but probably it doesn't. In which case 5+5+1+5 isn't quite enough because you need to fund the tx fee as well.

[TookDk]

It doesn't show the exact size... but you can roughly calculate it using the standard formula:

the size of the tx will be: 180 bytes per input + 34 bytes per output + 10 bytes.

That was what I was asking and I appreciate your will you tried to help me first!  I understand the calculation you wrote is a rough calculation that provides an estimated result for the tx, but it may be different in real because Mycelium tries to optimize the transaction. Well, even an estimated result is better than having no idea so I thank you!

Mycelium starts with the oldest output and adds more until enough value for the transaction was added, then goes through the outputs and checks whether some can get removed again.

...and if you wanted to send 16, it would choose the first four ones then remove nothing because 5 + 5 + 1 + 5 is 16 exactly. I hope I understand right, thank you! I could appreciate a feature to select my output option and also information about the exact fee before transaction, though.

I can further add to the discussion that I use both core and Mycelium, but for very different purpose.
I use core when I receive payment for trading etc. in other words relative large amounts that I need to keep safe. With core am I in full control. I run it on a dedicated PC. Downsides, its slow to sync, slow to start... but it is OK, since only actually use the application once in a while to "unload" my balance to other addresses.

For everyday use do I use Mycelium, I have found it to be extremely reliable, and the "priority" system works well, if setting to highest priority then does the tx always gets calculated in such a way that I my tx gets a priority for confirming (nothing is more frustrating that having a tx stuck in a medium priority when buying something). I also have the "normal" priority if speed is not an issue. I also find the "cold storage" option really useful, my favorite storage mediums are paper wallets, Mycelium is excellent in quickly sweeping these with the phone camera. I can sincerely recommend for day-to-day use. There is some apparent security issues, but they can be mitigated by not having large sums on you Mycelium wallet, since it is so easy to sweep paper wallets, it is very easy just to sweep a paper wallet to "fill up" your Mycelium wallet when needed.
 

[HCP]

… information about the exact fee before transaction …

Keep in mind that the ultimate effect of the fee amount, the speed of confirmation, is fundamentally very inexact. It may not be worth the trouble to aim for exactness here.

I think though that Mycelium displays the exact fee and changes it when you change the priority level.

This is correct... after you put in the amount you wish to send, on the "confirmation" screen... you get to see what fee the system has calculated for your transaction before you send it... you can also cycle through the fee levels (Low-prio, economic, normal, priority) by tapping the box...

see here: http://imgur.com/a/35oLU

It doesn't give you the exact transaction size... and it doesn't give fine grained control... having said that, I've used "low prio" for all my sends so far and they usually get confirmed within an hour or 2... I think the longest wait so far was 93minutes... but YMMV

Also, as mentioned, the fees are an inexact science and don't really guarantee any sort of confirmation time frame... just because you put a "priority" fee on a transaction, it doesn't obligate the miners to process your transaction in the next block... or ever.

[PremiumCodeX]

@TookDk, yeah, thank you for summing up your favorit features about Mycelium! As you wrote, it is not like if I use Mycelium I cannot use anything else, but I appreciate your positive feedback about the software, appreciate enough to want to try out Mycelium soon next to my current wallets.

Well, kind of. Usually when people talk about "hardware wallets" they mean some kind of device which can't be hacked due to the code it runs being very limited in scope, and uneditable without physically pressing some buttons on the device. Android on the other hand is a general purpose operating system and probably has many vulnerabilities and possibly even deliberate backdoors.

Oh I see. Hardware wallets are dedicated device. Its purposes is to keep the virtual wallet secure by limiting the possibilities of system vulnerabilities thanks to a minimalistic system and in addition it also restricts how a person ( or an other device ) can communicate with the wallet. However, according to this definition I wonder what if I bought a board with the physical controls I would want to use it with, installed a minimalistic Linux onto the board ( with the minimal software I need like Mycelium ) and set proper security rules? That also would be a  compact hardware with restricted system and minimalistic design.

If the 16 included the fee, yes, but probably it doesn't. In which case 5+5+1+5 isn't quite enough because you need to fund the tx fee as well.

You mean it is not that easy to pre-calculate the exact amount of output ( as @HCP pointed out too right above ) because the transaction size contains inexact parameters. I get that, I just wanted to point out I understood how the logical layer worked. But again, I got to know, the software displayed the exact tx parameter, at least.

[hgmichna]

Oh I see. Hardware wallets are dedicated device. Its purposes is to keep the virtual wallet secure by limiting the possibilities of system vulnerabilities thanks to a minimalistic system …

True, but you can create something almost like a hardware wallet with Mycelium. Take an Android smartphone. It can be one that is just barely capable of running Mycelium, because the idea is to run nothing or very little else on it.

Install Mycelium, then safeguard the phone. Lock it down. Do not install anything else on it that could possibly reduce your security. For example, take an older, but sufficient phone, install CyanogenMod on it, but not the Google apps. Now you have a minimalistic phone that does not even have the Google Play Store and has no connection to Google whatsoever.

Install Mycelium on it (by copying the APK file to the phone and installing it). Now, as long as you keep it safeguarded and inaccessible, you have something that is much more secure than any ordinary smartphone. True, it is not really a hardware wallet, but it comes fairly close.

Also read up on the true hardware wallets that work with Mycelium. I like my Trezor, for example, but there are at least two more hardware wallet types that work with Mycelium and that can keep even large bitcoin amounts safe while still allowing transactions with them.

[japerry]

Oh I see. Hardware wallets are dedicated device. Its purposes is to keep the virtual wallet secure by limiting the possibilities of system vulnerabilities thanks to a minimalistic system …

Also read up on the true hardware wallets that work with Mycelium. I like my Trezor, for example, but there are at least two more hardware wallet types that work with Mycelium and that can keep even large bitcoin amounts safe while still allowing transactions with them.

My Ledger HW.1 works great with a old Samsung S II. It's the perfect portable hardware wallet.

[Johnny00]

I think I'll just have to eat he fee sick I have many small outputs.  I remember pay on only 2 cents on two bit coins and since I have many small transactions I'm paying 15 cents.

[Sgmaster]

Hello, I am using mycelium for a few years now, although I had to make an electrum wallet for a specific reason. The thing is I really don't like the electrum app, its at least inconvenient. So I thought it would be great if I could import the wallet to mycelium so I can keep an eye on the electrum wallet without  having to use their terrible app. I tried importing the master key, although a notification appeared saying "Can only import account level 3 (xpub) addresses, this was level 0". What does this mean, and can I watch my electrum wallet through mycelium?
Thank you in advance.

[hgmichna]

Hello, I am using mycelium for a few years now, although I had to make an electrum wallet for a specific reason. The thing is I really don't like the electrum app, its at least inconvenient. So I thought it would be great if I could import the wallet to mycelium so I can keep an eye on the electrum wallet without  having to use their terrible app. I tried importing the master key, although a notification appeared saying "Can only import account level 3 (xpub) addresses, this was level 0". What does this mean, and can I watch my electrum wallet through mycelium? …

This question translates into, how can you export the private key from your Electrum wallet.

That however, is a question you may have to ask the Electrum people. You have to find a format that Electrum can export and Mycelium can import.

Another possibility could be a tool that can convert a level 0 master key representation into level 3.

I have no answers for any of these questions, just wanted to clarify. Does anybody know a way?

[TheFuzzStone]

ask the Electrum people.

Best answer I think

[Pro Gamers]

anyone can help? my phone went on bootloop yesterday so i had no choice but to reformat it, just what i did. and i retrieved it using my secret codes but the problem is its not my account i supposed to get i have three hd account, each has balances although not much because i was lucky that i transferred them before this happen, what does it means?

[gentlemand]

Have you pressed reload account on the accounts screen? I occasionally don't get a new deposit showing up. Reloading it does the job.

[Pro Gamers]

Have you pressed reload account on the accounts screen? I occasionally don't get a new deposit showing up. Reloading it does the job.

i just did now but still the same. sorry its my first time facing with this problem and what i dont get is after i create a new hd account, 47 private keys just appeared and in the transaction tab  there has input and output that i dont know where they came from.