User Guide¶

The Zcash repository is a fork of Bitcoin Core which contains protocol changes to support the Zerocash protocol. This implements the Zcash cryptocurrency, which maintains a separate ledger from the Bitcoin network, for several reasons, the most immediate of which is that the consensus protocol is different.

Getting Started¶

Welcome! This guide is intended to get you running on the official Zcash network. To ensure your Zcash client behaves gracefully throughout the setup process, please check your system meets the following requirements:

64-bit Linux OS
64-bit Processor
5GB of free RAM
10GB of free Disk (the size of the block chain increases over time)

Note

Currently we only officially support Linux (Debian), but we are actively investigating development for other operating systems and platforms(e.g. macOS, Ubuntu, Windows, Fedora).

Please let us know if you run into snags. We plan to make it less memory/CPU intensive and support more architectures and operating systems in the future.

If you are installing Zcash for the first time, please skip to the Installation section. Otherwise, the below upgrading section will provide information to update your current Zcash environment.

If you’re on a Debian-based distribution, you can follow the Debian Binary Packages Setup to install Zcash on your system. Otherwise, you can update your local snapshot of our code:

git fetch origin

Ensure you check the current release version from here .
If v2.0.0 was current, issue the following commands:
git checkout v2.0.0
./zcutil/fetch-params.sh
./zcutil/build.sh -j$(nproc)  Note If you don’t have nproc, then substitute the number of cores on your system. If the build runs out of memory, try again without the -j argument, i.e. just ./zcutil/build.sh. If you are upgrading from testnet, make sure that your ~/.zcash directory contains only zcash.conf to start with, and that your ~/.zcash/zcash.conf does not contain testnet=1 or addnode=testnet.z.cash. If the build fails, move aside your zcash directory and try again by following the instructions in the Installation section below. Important If you ran into any issues upgrading to Overwinter, please see the Network Upgrade Developer Guide Setup¶ There are a couple options to setup Zcash for the first time. 1. If you would like to install binary packages for Debian-based operating systems, see Debian Binary Packages Setup 2. If you would like to compile Zcash from source, please continue to the Installation section. Installation¶ Before we begin installing Zcash, we need to get some dependencies for your system. UBUNTU/DEBIAN sudo apt-get install \ build-essential pkg-config libc6-dev m4 g++-multilib \ autoconf libtool ncurses-dev unzip git python python-zmq \ zlib1g-dev wget curl bsdmainutils automake  FEDORA sudo dnf install \ git pkgconfig automake autoconf ncurses-devel python \ python-zmq wget curl gtest-devel gcc gcc-c++ libtool patch  RHEL (including Scientific Linux) • Install devtoolset-3 and autotools-latest (if not previously installed). • Run scl enable devtoolset-3 'scl enable autotools-latest bash' and do the remainder of the build in the shell that this starts. WINDOWS (cross-compile) Note As of 5/1/2018 this platform is not fully supported. However, we are actively working to complete the components to support this. To view active work on this platform, see: #3172 MAC Note As of 5/1/2018 this platform is not fully supported. However, we are actively working to complete the components to support this. To view active work on this platform, see: #2820 CENTOS 7+ sudo yum install \ autoconf libtool unzip git python \ wget curl automake gcc gcc-c++ patch \ glibc-static libstdc++-static  Please execute the below commands in order. sudo yum install centos-release-scl-rh sudo yum install devtoolset-3-gcc devtoolset-3-gcc-c++ sudo update-alternatives --install /usr/bin/gcc-4.9 gcc-4.9 /opt/rh/devtoolset-3/root/usr/bin/gcc 10 sudo update-alternatives --install /usr/bin/g++-4.9 g++-4.9 /opt/rh/devtoolset-3/root/usr/bin/g++ 10 scl enable devtoolset-3 bash  Please see our Supported Platform Policy for additional details. Next, we need to ensure we have the correct version of gcc , g++ , and binutils 1. gcc/g++ 4.9 or later is required. Zcash has been successfully built using gcc/g++ versions 4.9 to 7.x inclusive. Use g++ --version or gcc --version to check which version you have. On Ubuntu Trusty, if your version is too old then you can install gcc/g++ 4.9 as follows: $ sudo add-apt-repository ppa:ubuntu-toolchain-r/test
$sudo apt-get update$ sudo apt-get install g++-4.9

2. binutils 2.22 or later is required.

Use as --version to check which version you have, and upgrade if necessary.

Now we need to get the Zcash software from the repository:

git clone https://github.com/zcash/zcash.git
cd zcash/
git checkout v2.0.0
./zcutil/fetch-params.sh


This will fetch both our Sprout proving and verifying keys (the final ones created in the Parameter Generation Ceremony) in addition to the parameters generated in the Sapling MPC which are used once Sapling activates, and place them into ~/.zcash-params/. These keys are just under 1.7GB in size, so it may take some time to download them. Users upgrading from earlier 1.x releases will need to download the additional Sapling parameters which are just under 800MB in size.

The message printed by git checkout about a “detached head” is normal and does not indicate a problem.

Build¶

Ensure you have successfully installed all system package dependencies as described above. Then run the build, e.g.:

./zcutil/build.sh -j$(nproc)  Attention If you recieved any errors, from the above command, please check out our Troubleshooting Guide Note This should compile our dependencies and build zcashd. (Note: if you don’t have nproc, then substitute the number of cores on your system. If the build runs out of memory, try again without the -j argument, i.e. just ./zcutil/build.sh. Configuration¶ Following the steps below will create your zcashd configuration file which can be edited to either connect to mainnet or testnet as well as applying settings to safely access the RPC interface. Tip For a complete list of parameters used in zcash.conf, please check out Zcash.conf Guide Create the ~/.zcash directory: mkdir -p ~/.zcash  Mainnet¶ Place a configuration file at ~/.zcash/zcash.conf using the following commands: Warning Note that this will overwrite any zcash.conf settings you may have added from testnet. (If you want to run on testnet, you can retain a zcash.conf from testnet.) echo "addnode=mainnet.z.cash" >~/.zcash/zcash.conf  Example configured for mainnet : zcash.conf addnode=mainnet.z.cash  Testnet¶ After running the above commands to create the zcash.conf file, edit the following parameters in your zcash.conf file to indicate network and node discovery for testnet: • add the line testnet=1 • addnode=testnet.z.cash instead of addnode=mainnet.z.cash Example configured for testnet: zcash.conf testnet=1 addnode=testnet.z.cash  Enabling CPU Mining¶ If you want to enable CPU mining, run these commands: echo 'gen=1' >> ~/.zcash/zcash.conf echo "genproclimit=-1" >> ~/.zcash/zcash.conf  Setting genproclimit=-1 mines on the maximum number of threads possible on your CPU. If you want to mine with a lower number of threads, set genproclimit equal to the number of threads you would like to mine on. The default miner is not efficient, but has been well reviewed. To use a much more efficient but unreviewed solver, you can run this command: echo 'equihashsolver=tromp' >> ~/.zcash/zcash.conf  Note, you probably want to read the Zcash Mining Guide to learn more mining details. Usage¶ Now, run zcashd! ./src/zcashd  To run it in the background (without the node metrics screen that is normally displayed) use ./src/zcashd --daemon. Important If you are running Zcash for the first time you will need to allow your node to fully sync:  :88SX@888@@X8: 8; %X X% ;8 %%Xt%tt%SSSSS:XXXt@@ X :: :: X @S;;tt%%%t ;;::XXXXSX % SS % .t:::;;%8888 88888tXXXX8; S S .%...:::8 8::XXX%; X X 8888...:t888888X 8t;;::XX8 8 8 %888888...:::;:8 :Xttt;;;::X@ 888888888...:St 8:%%tttt;;;:X X X 88888888888S8 :%;ttt%%tttt;;X 8 8 %888888888%t 8S:;;;tt%%%ttt;8 : : 8t8888888 S8888888Stt%%%t@ :: :: .@tt888@ 8;;ttt@; t t .8ttt8@SSSSS SXXXX%:;;;X; 8 8 X8ttt8888% %88...::X8 X. .X %8@tt88;8888%8888%8X :; ;: :@888@XXX@888: tt Thank you for running a Zcash node! You're helping to strengthen the network and contributing to a social good :) In order to ensure you are adequately protecting your privacy when using Zcash, please see <https://z.cash/support/security/>. Block height | 319430 Connections | 8 Network solution rate | 508319381 Sol/s You are currently not mining. To enable mining, add 'gen=1' to your zcash.conf and restart. Since starting this node 9 minutes, 1 seconds ago: - You have validated 7815 transactions! [Press Ctrl+C to exit] [Set 'showmetrics=0' to hide]  Notice 319430, in the above output, after the Block height field, this means your zcashd is fully synced. Alternatively, if you were NOT fully synced your output would look similar to below:  :88SX@888@@X8: 8; %X X% ;8 %%Xt%tt%SSSSS:XXXt@@ X :: :: X @S;;tt%%%t ;;::XXXXSX % SS % .t:::;;%8888 88888tXXXX8; S S .%...:::8 8::XXX%; X X 8888...:t888888X 8t;;::XX8 8 8 %888888...:::;:8 :Xttt;;;::X@ 888888888...:St 8:%%tttt;;;:X X X 88888888888S8 :%;ttt%%tttt;;X 8 8 %888888888%t 8S:;;;tt%%%ttt;8 : : 8t8888888 S8888888Stt%%%t@ :: :: .@tt888@ 8;;ttt@; t t .8ttt8@SSSSS SXXXX%:;;;X; 8 8 X8ttt8888% %88...::X8 X. .X %8@tt88;8888%8888%8X :; ;: :@888@XXX@888: tt Thank you for running a Zcash node! You're helping to strengthen the network and contributing to a social good :) In order to ensure you are adequately protecting your privacy when using Zcash, please see <https://z.cash/support/security/>. Downloading blocks | 319610 / ~320290 (99%) Connections | 6 Network solution rate | 389211802 Sol/s You are currently not mining. To enable mining, add 'gen=1' to your zcash.conf and restart. Since starting this node 59 seconds ago: - You have validated 7144 transactions! [Press Ctrl+C to exit] [Set 'showmetrics=0' to hide]  Notice now how the Block height field has changed to Downloading blocks with value 319610 / ~320290 (99%). This indicates that your node is attempting to sync with the current block height. You should be able to use the RPC after it finishes syncing. If you are running zcashd in the background, issue the below command to test: ( If you did not run zcashd in the background, you will need to open a new terminal) ./src/zcash-cli getinfo  Note If you are familiar with bitcoind’s RPC interface, you can use many of those calls to send ZEC between t-addr addresses. We do not support the ‘Accounts’ feature (which has also been deprecated in bitcoind) — only the empty string "" can be used as an account name. The main network node at mainnet.z.cash is also accessible via Tor hidden service at zcmaintvsivr7pcn.onion. Using Zcash¶ First, you want to obtain Zcash. You can purchase them from an exchange, from other users, or sell goods and services for them! Exactly how to obtain Zcash (safely) is not in scope for this document, but you should be careful. Avoid scams! Important Terminology Zcash supports two different kinds of addresses, a z-addr (which begins with a z) is an address that uses zero-knowledge proofs and other cryptography to protect user privacy. There are also t-addrs (which begin with a t) that are similar to Bitcoin’s addresses. The interfaces are a commandline client (zcash-cli) and a Remote Procedure Call (RPC) interface, which is documented here: Zcash Payment API Attention Wallet Backup To ensure you have properly backedup your wallet, we strongly encourage you to review the Wallet Backup Instructions . Generating a t-addr¶ Let’s generate a t-addr first. If you are running zcashd for the first time, you can issue zcash-cli getaddressesbyaccount "" to view existing addresses. $ ./src/zcash-cli getnewaddress
t14oHp2v54vfmdgQ3v3SNuQga8JKHTNi2a1


$./src/zcash-cli getaddressesbyaccount ""  This should show the address that was just created. Receiving Zcash with a z-addr¶ Now let’s generate a z-addr. $ ./src/zcash-cli z_getnewaddress
zcBqWB8VDjVER7uLKb4oHp2v54v2a1jKd9o4FY7mdgQ3gDfG8MiZLvdQga8JK3t58yjXGjQHzMzkGUxSguSs6ZzqpgTNiZG


This creates a private address and stores its key in your local wallet file. Give this address to the sender!

A z-addr is pretty large, so it’s easy to make mistakes with them. Let’s put it in an environment variable to avoid mistakes:

$ZADDR='zcBqWB8VDjVER7uLKb4oHp2v54v2a1jKd9o4FY7mdgQ3gDfG8MiZLvdQga8JK3t58yjXGjQHzMzkGUxSguSs6ZzqpgTNiZG'  Listing z-addr¶ To get a list of all addresses in your wallet for which you have a spending key, run this command: $ ./src/zcash-cli z_listaddresses


You should see something like:

[
{
"txid" : "af1665b317abe538148114a45322f28151925501c081949cc7a5207ef21cb750",
"amount" : 1.23,
"memo" : "48656c6c6f20ceb2210000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
}
]


If someone gives you their z-addr…

$FRIEND='zcCDe8krwEt1ozWmGZhBDWrcUfmK3Ue5D5z1f6u2EZLLCjQq7mBRkaAPb45FUH4Tca91rF4R1vf983ukR71kHyXeED4quGV'  You can send 0.8 ZEC by doing… $ ./src/zcash-cli z_sendmany "$ZADDR" "[{\"amount\": 0.8, \"address\": \"$FRIEND\"}]"


After waiting about a minute, you can check to see if the operation has finished and produced a result:

\$ ./src/zcash-cli z_getoperationresult

[
{
"id" : "opid-4eafcaf3-b028-40e0-9c29-137da5612f63",
"status" : "success",
"creation_time" : 1473439760,
"result" : {
},
"execution_secs" : 51.64785629
}
]


As Zcash is an extension of bitcoin, zcash-cli supports all commands that are part of the Bitcoin Core API (as of version 0.11.2), https://en.bitcoin.it/wiki/Original_Bitcoin_client/API_calls_list

For a full list of new commands that are not part of bitcoin API (mostly addressing operations on z-addrs) see Zcash Payment API

To list all Zcash commands:

./src/zcash-cli help


To get help with a particular command:

./src/zcash-cli help <command>


Attention

Known Security Issues

Each release contains a ./doc/security-warnings.md document describing security issues known to affect that release. You can find the most recent version of this document here:

Security Warnings

Please also see our security page for recent notifications and other resources:

https://z.cash/support/security.html