Monero is a private, secure, untraceable, decentralised digital currency. You are your bank, you control your funds, and nobody can trace your transfers unless you allow them to do so.
**Privacy:** Monero uses a cryptographically sound system to allow you to send and receive funds without your transactions being easily revealed on the blockchain (the ledger of transactions that everyone has). This ensures that your purchases, receipts, and all transfers remain absolutely private by default.
**Security:** Using the power of a distributed peer-to-peer consensus network, every transaction on the network is cryptographically secured. Individual wallets have a 25 word mnemonic seed that is only displayed once, and can be written down to backup the wallet. Wallet files are encrypted with a passphrase to ensure they are useless if stolen.
**Untraceability:** By taking advantage of ring signatures, a special property of a certain type of cryptography, Monero is able to ensure that transactions are not only untraceable, but have an optional measure of ambiguity that ensures that transactions cannot easily be tied back to an individual user or computer.
This is the core implementation of Monero. It is open source and completely free to use without restrictions, except for those specified in the license agreement below. There are no restrictions on anyone creating an alternative implementation of Monero that uses the protocol and network in a compatible manner.
As with many development projects, the repository on Github is considered to be the "staging" area for the latest changes. Before changes are merged into that branch on the main repository, they are tested by individual developers in their own branches, submitted as a pull request, and then subsequently tested by contributors who focus on testing and code reviews. That having been said, the repository should be carefully considered before using it in a production environment, unless there is a patch in the repository for a particular show-stopping issue you are experiencing. It is generally a better idea to use a tagged release for stability.
**Anyone is welcome to contribute to Monero's codebase!** If you have a fix or code change, feel free to submit it as a pull request directly to the "master" branch. In cases where the change is relatively small or does not affect other parts of the codebase it may be merged in immediately by any one of the collaborators. On the other hand, if the change is particularly large or complex, it is expected that it will be discussed at length either well in advance of the pull request being submitted, or even directly on the pull request.
Monero is a 100% community-sponsored endeavor. If you want to join our efforts, the easiest thing you can do is support the project financially. Both Monero and Bitcoin donations can be made to **donate.getmonero.org** if using a client that supports the [OpenAlias](https://openalias.org) standard. Alternatively you can send XMR to the Monero donation address via the `donate` command (type `help` in the command-line wallet for details).
The Monero donation address is: `44AFFq5kSiGBoZ4NMDwYtN18obc8AemS33DBLWs3H7otXft3XjrpDtQGv7SqSsaBYBb98uNbr2VBBEt7f2wfn3RVGQBEP3A` (viewkey: `f359631075708155cc3d92a32b75a7d02a5dcf27756707b47a2b31b21c389501`)
There are also several mining pools that kindly donate a portion of their fees, [a list of them can be found on our Bitcointalk post](https://bitcointalk.org/index.php?topic=583449.0).
Monero uses a fixed-schedule mandatory software upgrade (hard fork) mechanism to implement new features. This means that users of Monero (end users and service providers) need to run current versions and upgrade their software on a regular schedule. Mandatory software upgrades occur during the months of March and September. The required software for these upgrades will be available prior to the scheduled date. Please check the repository prior to this date for the proper Monero software version. Below is the historical schedule and the projected schedule for the next upgrade.
Approximately three months prior to a scheduled mandatory software upgrade, a branch from Master will be created with the new release version tag. Pull requests that address bugs should then be made to both Master and the new release branch. Pull requests that require extensive review and testing (generally, optimizations and new features) should *not* be made to the release branch.
Installing a snap is very quick. Snaps are secure. They are isolated with all of their dependencies. Snaps also auto update when a new version is released.
build the library binary manually. This can be done with the following command ```sudo apt-get install libgtest-dev && cd /usr/src/gtest && sudo cmake . && sudo make && sudo mv libg* /usr/lib/ ```
Tested on a Raspberry Pi Zero with a clean install of minimal Raspbian Stretch (2017-09-07 or later) from https://www.raspberrypi.org/downloads/raspbian/. If you are using Raspian Jessie, [please see note in the following section](#note-for-raspbian-jessie-users).
If you are using the older Raspbian Jessie image, compiling Monero is a bit more complicated. The version of Boost available in the Debian Jessie repositories is too old to use with Monero, and thus you must compile a newer version yourself. The following explains the extra steps, and has been tested on a Raspberry Pi 2 with a clean install of minimal Raspbian Jessie.
* As before, `apt-get update && apt-get upgrade` to install all of the latest software, and increase the system swap size
```
sudo /etc/init.d/dphys-swapfile stop
sudo nano /etc/dphys-swapfile
CONF_SWAPSIZE=1024
sudo /etc/init.d/dphys-swapfile start
```
* Then, install the dependencies for Monero except `libunwind` and `libboost-all-dev`
* Install the latest version of boost (this may first require invoking `apt-get remove --purge libboost*` to remove a previous version if you're not using a clean install):
* From here, follow the [general Raspberry Pi instructions](#on-the-raspberry-pi) from the "Clone monero and checkout most recent release version" step.
* Edit the properties for the `MSYS2 Shell` shortcut changing "msys2_shell.bat" to "msys2_shell.cmd -mingw64" for 64-bit builds or "msys2_shell.cmd -mingw32" for 32-bit builds
The project can be built from scratch by following instructions for Linux above. If you are running monero in a jail you need to add the flag: `allow.sysvipc=1` to your jail configuration, otherwise lmdb will throw the error message: `Failed to open lmdb environment: Function not implemented`.
The Boost package has a bug that will prevent librpc.a from building correctly. In order to fix this, you will have to Build boost yourself from scratch. Follow the directions here (under "Building Boost"):
By default, in either dynamically or statically linked builds, binaries target the specific host processor on which the build happens and are not portable to other processors. Portable binaries can be built using the following targets:
This section contains general instructions for debugging failed installs or problems encountered with Monero. First ensure you are running the latest version built from the Github repo.
We generally use the tool `gdb` (GNU debugger) to provide stack trace functionality, and `ulimit` to provide core dumps in builds which crash or segfault.
* To use gdb in order to obtain a stack trace for a build that has stalled:
Run the build.
Once it stalls, enter the following command:
```
gdb /path/to/monerod `pidof monerod`
```
Type `thread apply all bt` within gdb in order to obtain the stack trace
* If however the core dumps or segfaults:
Enter `ulimit -c unlimited` on the command line to enable unlimited filesizes for core dumps
When it terminates with an output along the lines of "Segmentation fault (core dumped)", there should be a core dump file in the same directory as monerod. It may be named just `core`, or `core.xxxx` with numbers appended.
Instructions for debugging suspected blockchain corruption as per @HYC
There is an `mdb_stat` command in the LMDB source that can print statistics about the database but it's not routinely built. This can be built with the following command:
`cd ~/monero/external/db_drivers/liblmdb && make`
The output of `mdb_stat -ea <path to blockchain dir>` will indicate inconsistencies in the blocks, block_heights and block_info table.
The output of `mdb_dump -s blocks <path to blockchain dir>` and `mdb_dump -s block_info <path to blockchain dir>` is useful for indicating whether blocks and block_info contain the same keys.
These records are dumped as hex data, where the first line is the key and the second line is the data.
