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[Request] A tweak to control the bitcoin: url handler on ios. Be able to set default bitcoin wallet application for links to open.
I have numerous Bitcoin apps on my iPhone. I've had the BlockChain.info wallet for a long time and it has always automatically handled "bitcoin:" URIs. However, I recently installed the CoinJar app and it apparently took the liberty of deeming itself as the default URI handler for "bitcoin:". I didn't mind much at the time, but now that the eGifter app accepts BTC in-app (!!!), I find myself buying small gift cards here and there. Would be nice to be able to actually have my BCi wallet handle all payments again - would make purchases actually easier than credit card! I have a feeling it might work to uninstall CoinJar, but at the same time, I don't want to uninstall it because it's no longer available so I'll be saying "bye bye" to it forever! Any help would be much appreciated. Thanks!
Question about file size with Bitcoin Wallet Application
I have the Bitcoin Wallet application running on my computer. I haven't opened it in a long time, so right now it is synchronizing with the network. In the process it is creating some massive files(and growing): -blk0001.dat 2GB -blk0002.dat 2GB -blk0004.dat 350mb -blkindex.dat 1.3GB Are these files necessary? Is there another wallet I can use? Can I delete them? What are they for? Thanks
I’ve been storing several different cryptos on applications like Electrum, Exodus and Trust Wallet. I’ve been thinking about going to a device like the Ledger Nano S for more security, but is it really that much more secure than especially Electrum? (x-post from /r/Bitcoin)
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Open Bitcoin Privacy Protect Privacy Questionnaire, Mid-Year 2015 report | wei at openbitcoinprivacyproject.org | Aug 07 2015
wei at openbitcoinprivacyproject.org on Aug 07 2015: Hi, Hope it is OK to post this on the list, was not sure where else to post for answers from Bitcoin-Qt client developers. As part of the Open Bitcoin Privacy Project’s ongoing wallet privacy measurement efforts, we’ve selected the Bitcoin-Qt client v0.11.0 for inclusion into our 2015 mid year survey. While our volunteers will be performing a series of functional tests by interacting with your application directly, several of the features we’d like to examine are not easily discernible by non-developers, and for this reason we’re asking for your help. If you can answer the following questions about your wallet’s behavior it will assist us with the process of accurately rating your wallet’s privacy features.
Does your application take any steps to create ambiguity between
transactions which unavoidably spend from multiple addresses at the same time and intentional mixing transactions?
What algorithms does your application use for ordering inputs and
outputs in a transaction? In particular, how do you handle the change output and do you take into account common practices of other wallet applications when determining ordering?
Does your application minimize the harmful effects of address reuse
by spending every spendable input (“sweeping”) from an address when a transaction is created?
Does your application fully implement BIP 62?
If your application supports mixing:
a. What is the average number of participants a user can expect to interact with on a typical join transaction? b. Does your application attempt to construct join transactions in a way that avoids distinguishing them from non-join transactions? c. Does your application perform any kind of reversibility analysis on join transactions prior to presenting them to the user for confirmation? d. Is the mixing technique employed secure against correlation attacks by the facilitator, such as a CoinJoin server or off-chain mixing service? e. Is the mixing technique employed secure against theft of funds by the facilitator or its participants? Donations
If your application has a fee or donation to the developers feature:
a. What steps do you take to make the donations indistinguishable from regular spend in terms of output sizes and destination addresses? Balance Queries and Tx Broadcasting
Please describe how your application obtains balance information in
terms of how queries from the user’s device can reveal a connection between the addresses in their wallet. a. Does the application keep a complete copy of the blockchain locally (full node)? b. Does the user’s device provide a filter which matches some fraction of the blockchain while providing a false positive rate (bloom or prefix filters)? i. If so, approximately what fraction of the blockchain does the filter match in a default configuration (0% - 100%)? c. Does the user’s device query all of their addresses at the same time? d. Does the user’s device query addresses individually in a manner that does not allow the query responder to correlate queries for different addresses? e. Can users opt to obtain their balance information via Tor (or equivalent means)?
Does the applications route outgoing transactions independently from
the manner in which it obtains balance information? Can users opt to have their transactions submitted to the Bitcoin network via Tor (or an equivalent means) independently of how they obtain their balance information?
If your application supports multiple identities/wallets, does each
one connect to the network as if it were completely independent from the other? a. Does the application ever request balance information for addresses belonging to multiple identities in the same network query? b. Are outgoing transactions from multiple identities routed independently of each other to the Bitcoin network? c. When an identity/wallet is deleted, does the deletion process eliminate all evidence from the user's device that the wallet was previously installed?
When a user performs a backup operation for their wallet, does this
generate any automatic network activity, such as a web query or email?
Does your application perform any lookup external to the user’s
device related to identifying transaction senders or recipients?
Does you application connect to known endpoints which would be
visible to an ISP, such as your domain?
If your application connects directly to nodes in the Bitcoin P2P
network, does it either use an unremarkable user agent string (Bitcoin Core. BitcoinJ, etc), or randomize its user agent on each connection?
Does the application uninstall process for your application
eliminate all evidence from the user's device that the application was previously installed? Does it also eliminate wallet data?
Does your application use techniques such as steganography to store
persistent wallet metadata in a form not identifiable as belong to a Bitcoin wallet application?
Please describe the degree to which users can use passwords/PINs to
protect their data: a. Can the user set a password/PIN to protect their private keys? b. Can the user set a password/PIN to protect their public keys and balance information? c. Can the user set a password/PIN to encrypt other wallet metadata, such as address books and transaction notes? d. Does the application use a single password/PIN to cover all protected data, or does it allow the use of multiple passwords/PINs? Custodianship
Do you as a wallet provider ever have access to unencrypted copies
of the user’s private keys, public keys, or any other wallet metadata which may be used to associate a user with their transactions or balances?
If your application reports telemetry data, such as usage
information or automatic crash reporting, does the user have the opportunity to review and approve all information transmitted before it is sent?
Source Code and Building
Can a user of your application compile the application themselves in
a manner that produces a binary version identical to the version you distribute (deterministic build system)? Thank you for assisting us with this effort to measure privacy progress in the Bitcoin wallet space. If at all possible, please return this survey before 2015/08/13 to ensure the score for your application will be as accurate as possible. Sincerely, Wei Open Bitcoin Privacy Project Contributor original: http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-August/010006.html
An exhaustive look at private keys for the uninitiated.
I wrote this explanation of private keys several months ago for folks in /BitcoinBeginners, but I thought some of the new people here might get some benefit out of it. There is no TL;DR. Sorry for the length! Any corrections or clarifications are welcome and appreciated! A private key is just a really big number--that's it. If someone discovers the number you've chosen to use as your private key, they will be able to access any bitcoins assigned to that number. This may seem disconcerting at first. After all, if someone were to just happen to guess your number, they would have access to all your bitcoins, right? But many types of security come down to knowing or possessing something that is difficult to guess or reproduce. For example, a Master brand combination padlock with a 3 number combination on a dial with 0-36 has around 50,653 possible combinations (373 ). A typical pin-tumbler lock today has 5 pins with each pin having only about 10 different height levels meaning that there are only 100,000 (105 ) effective combinations for an average house key. Even a credit card number is only 15 characters long with 10 digits per character. That means there are only 1015 possible combinations of credit card numbers which is equivalent to about 1 quadrillion (there is some added security by combining that number with an expiration date and 3-digit security code, but I'm ignoring that for now). The point is, we're accustomed to using much smaller pools of possible combinations to protect many parts of our lives today. By comparison, a private key for Bitcoin begins as a 256-bit number or a number that is 256 characters long with 2 digits per character (a bit in the binary number system that computers understand is either 1 or 0), which is 2256. That's huge. How huge? Remember that 1015 was equal to a quadrillion? A 256-bit private key used for Bitcoin can be any number between 0 and 115 quattuorvigintillion 792 trevigintillion 89 duovigintillion 237 unvigintillion 316 vigintillion 195 novemdecillion 423 octodecillion 570 septendecillion 985 sexdecillion 8 quindecillion 687 quattuordecillion 907 tredecillion 852 duodecillion 837 undecillion 564 decillion 279 nonillion 74 octillion 904 septillion 382 sextillion 605 quintillion 163 quadrillion 141 trillion 518 billion 161 million 494 thousand 336. In reality (because of some of the fancy math we do to that 256-bit number to make it a bit more useable create the public key pair value which we will use as the address), some of the available addresses will overlap, so the actual pool of available addresses is more like 2160, but we're still talking about a gigantic number of possible addresses. To give you some context on the sheer scale of 2160, the number of grains of sand on the Earth is estimated at about 266. The number of stars in the universe is estimated at about 276. There are approximately 296 atoms in a cubic meter of water, and the number of atoms in the sun is estimated at 2190. Need a visual comparison? This graph shows the number of available Bitcoin addresses compared to the width of the universe in Zeptometers (one Zeptometer is one quintillionth of a meter) and the age of the universe in Yoctoseconds (one Yoctosecond is one sextrillionth of a second). So your private key with its 2160 possible combinations should be pretty safely hidden. Even a computer that could execute 1013 instructions per second would take around 5 trillion years to guess your private key. Since most humans can't keep a number in the quatturovigintillion's in their head, there are a number of tricks we can use to make it easier to manage. One thing we can do is to reduce the number of characters we have to remember, and the way to do that is to change the numerical base we use. Computers represent numbers in binary (also called base 2) which means every digit in the number is either a 0 or 1. To represent a private key in base 2, we have to use 256 places. To represent the same number in the base 10 we most commonly use, where each digit can be 0-9, we would only need 77 places. So, the higher the base, the smaller the resulting string. Base 16 (also known as hexadecimal) uses 0-9 and A-F for a total of 16 different possibilities for each digit. This reduces the number of places needed to represent the number to 64. There are many other bases that use different characters to represent more and more of the number, but the most common numerical base to use for Bitcoin addresses is Base 58 (actually, it's a special version of Base 58 called Base58Check which only uses characters that are not easily confused visually like 0 and O, and includes a 32-bit checksum appended to the payload, and has an extra step to preserve leading zero bytes). The result is a string of letters and numbers that is usually about 51 characters long. Of course, if you don't want to waste time trying to memorize a string of 51 characters, most of us trust our Bitcoin wallet applications to write that number to a file and to keep track of it for us. But anytime you write down your key, you make it vulnerable to being discovered, especially if the thing you write it on is connected to the Internet. This is why it is smart to encrypt the file containing your private key. And this is where some people get confused: The passphrase for your private key, in this example, is only for locally decrypting a file on your computer or device that stores your private key. It is not for using or accessing the private key itself. You cannot passphrase-protect the ability to use your private key to prevent an unauthorized person from using your private key, you can only take steps to hide what that key actually is. Another way you can hide your private key to make it easier to transport on paper is by using an encryption process developed specifically for Bitcoin addresses known as BIP38 (BIP stands for Bitcoin Improvement Proposal). BIP38 allows you to create a new address which looks similar to a Bitcoin private key, but will not function as one directly. Instead, you will need to decrypt the BIP38 address using a program that understands how to decrypt BIP38 using the passphrase that encrypted the address. This is a handy process because you can carry a BIP38 protected address around on a piece of paper, and as long as you remember the passphrase, your bitcoins should remain safe even if the paper is stolen or lost. Again, this doesn't protect someone from using your private key if they discover it in some other way, but it will conceal your private key when you write it down to make it more difficult to discover. Now, you may have heard in some cases that a passphrase is a private key. This may be confusing, but this is just referring to another way to keep track of this very large number. There are mathmatical formulas that can take data of any length and by passing it through the formula they create a number with the same number of bits every time. These formulas are called hashing algorithms. One such hashing algorithm is called SHA-256 which can take data of any length and produce a 256-bit number from it. You could give it a single word that's 6 letters long, or give it a text file with all the collected works of William Shakespeare in it and each one would produce a unique 256-bit number. And because of the properties of the formula, as long as you feed it the same data that you did originally it will always produce the same number as a result (called a hash). So, when someone tells you that their passphrase is their private key, they mean that they have fed their passphrase through a hashing algorithm to produce a 256-bit number from which they can use as their private key. This process is also known as a brain wallet. While this may seem clever you're essentially pitting your memory capacity against a cracker with a computer, and the odds are the computer will win. Please avoid using brain wallets if you have the choice. If your private key is ever exposed or if it can ever be calculated using a hashing algorithm, that is all someone needs to take any bitcoins contained in that address, so take good care of it! edit: just clarifying a couple of points edit2: updated the name of the number between which private keys can be used, and clarifying that the math is applied to the public key which is what introduces the potential for collisions edit3: clarifying what Base58Check differs from Base58
I already sent email to the official Ledger support address, so i'll just copy paste it here to explain the issue. Dear Ledger, I just got my Nano S from the mail. I ordered it from your official website. I have now configured the device and everything went as expected, until I tried to open a wallet application on Ledger (with the Ledger manager open on the PC). Whenever I try to open for example the Bitcoin wallet application on the physical Ledger, a message pops up on the Ledger manager application with this text: "To begin, connect your Ledger wallet. If asked, enter your PIN code to unlock your device". I can run the Ledger manager app just fine, install and manage applications etc. The issue is whenever I want to open a wallet application. The apps (included in the manager) I have tried so far are Bitcoin, Ethereum, Ark and Neo. All have the same issue. I have tried 3 different USB cables (TWO different official Ledger cables), re-installing Google Chrome, re-installing the apps inside the Ledger, completely resetting the Ledger wallet, re-installing Ledger manager. I have also tried it with another computer (Windows 10 on both) with the same results. Also rebooting Windows multiple times with no results. Also, the "Need assistance?" link in the Ledger app (prompted when trying to open a wallet) gives an 404 page not found error. I have found several other people having the same issue, and tried to solve mine with no result. Please help me resolve this.
ledger Blue synchronizes with some currencies, but not others?
Recently, I haven't been able to get my Ledger Blue to synch with the Ledger Bitcoin Wallet application. However, bizarrely, some other currencies pull up my wallet in the app right away. Currencies that don't work with my wallet app are; Bitcoin, Ripple, and Fido U2F. Currencies that do work with my wallet app: Dash, Litecoin, and Zcash. The Ethereum wallet (separate application) doesn't seem to be working for me either. Does anyone know what might be causing this, and how it can be fixed?
[Request] can someone compile this Github project? Xcode is required.
This is one of my priorities right now having a jailbroken phone. There is already a Bitcoin wallet application ready to compile on Github but I don't have XCode. If someone could compile it into a package and send it to me that would be awesome: https://github.com/voisine/zincwallet Someone else on /Bitcoin said they managed to compile it with XCode on their Mac. I managed to run 'git clone https://github.com/voisine/zincwallet.git' on my iPhone but I don't know how to progress from there. Here are installation instructions for XCode users: https://github.com/voisine/zincwallet/blob/masteINSTALL If anyone can do this it would be amazing! Thanks! Edit: if it's unclear: I would love if someone can compile that into a .deb package or .ipa (which I would need AppSync...) so I can get it running on my device. Thanks again!
Apple Publishes Revised Cryptocurrency, ICO Guidelines for App Store
https://preview.redd.it/blzhs1zenf311.jpg?width=760&format=pjpg&auto=webp&s=060f978786eac7b2822962194b4cc369e0baa199 Apple has revealed its revised guidelines in a dedicated section for iOS and MacOS apps centered on the cryptocurrency space. As bitcoin prices peaked near $20,000 in December 2017, Apple unveiled a new section of guidelines specific to cryptocurrencies and ICOs on December 20th. For instance, apps facilitating any exchange or transfer of cryptocurrencies like bitcoin were mandated to abide in compliance with all federal and relevant state laws of its offering. Under the mandated rules. On Monday June 4th, Apple expanded on those crypto-centric guidelines with several key inclusions into specific functionalities like wallet storage and mining for apps on its App Store platform. To keep its hardware, think iPhones, from draining battery or computing power, Apple has now forbid app developers from including any 3rd party advertisements that run cryptocurrency mining. The move comes at a time when ‘cryptojacking’, a malware attack wherein malicious attackers scrumptiously hijack a computer or a phone’s computing power to mine cryptocurrencies, is a growing menace. “Apps, including any third-party advertisements displayed within them, may not run unrelated background processes, such as cryptocurrency mining,” the updated policy reads. Apple has also outlawed apps from mining cryptocurrencies on the device altogether. An excerpt from the revised guidelines states: Apps may not mine for cryptocurrencies unless the processing is performed off device (e.g. cloud-based mining). ICO Norms In sticking with the original mandate, only mainstream banks and similar financial institutions will be allowed to develop and publish apps enabling crypto futures trading and initial coin offerings, Apple said. “Apps facilitating Initial Coin Offerings (“ICOs”), cryptocurrency futures trading, and other crypto-securities or quasi-securities trading must come from established banks, securities firms, futures commission merchants (“FCM”), or other approved financial institutions and must comply with all applicable law,” read the unchanged policy first unveiled in December. Wallets, Exchanges and Rewards Four years ago, Apple removed every single bitcoin wallet application on its App Store, including popular wallet app Blockchain. The technology giant reversed its stance soon after, despite pulling moves like removing multi-cryptocurrency wallet Jaxx after its disapproval of Dash in 2016. Speaking to CCN at the time, Jaxx CEO Anthony Di Iorio revealed Apple had stuck to approving a select six cryptocurrencies, namely: Bitcoin, Ethereum, Dogecoin, Litecoin, Ripple and the then DAO token. In July 2017, Apple ‘approved’ Dash as a cryptocurrency. Six months after crypto exchange Coinbase’s app became the number one trending app on the App Store, Apple has now apps to provide wallet services under a caveat. “Apps may facilitate virtual currency storage, provided they are offered by developers enrolled as an organization,” the policy states. Similarly, Apple is also allowing apps to facilitate crypto transactions “on an approved exchange, provided they are offered by the exchange itself.” Finally, the world’s most valuable company has also mandated that apps do not offer cryptocurrency as rewards to users for completing tasks. It states: Cryptocurrency apps may not offer currency for completing tasks, such as downloading other apps, encouraging other users to download, posting to social networks, etc. Source
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