# SilentDragonPaper
SilentDragonPaper is a paper wallet generator that can run completely offline.
You can run it on an air-gapped computer to generate your shielded z-addresses, which will allow you to keep your keys completely offline.
*Example:*
## Download
### Binary installation
SilentDragonPaper is available as pre-built binaries from our [release page](https://git.hush.is/hush/SilentDragonPaper/releases). Download the zip file for your platform, extract it and run the `./SilentDragonPaper` binary.
### Source code installation
If you decide to compile from source, then first use git to get the source code as follows:
```
git clone https://git.hush.is/hush/SilentDragonPaper
```
Then choose one of these two source compilation options to build the SilentDragonPaper CLI.
#### Option 1: Compile using system installed rust
SilentDragonPaper is built with rust. To compile from source, you [install Rust](https://www.rust-lang.org/tools/install).
```
cd SilentDragonPaper/cli
cargo build --release
```
#### Option 2: Compile using "embedded" rust
Here we do not need a system installed rust to compile. The build.sh script pulls Rust version 1.48 down for us and builds with it.
```
cd SilentDragonPaper/cli
./build.sh
```
#### Compiled binary location
The completed binary is available in the `cli/target/release` folder.
## Usage Instructions
### Generating wallets
To generate a Hush paper wallet, simply run `./SilentDragonPaper` or `./target/release/SilentDragonPaper` or `./cli/target/release/SilentDragonPaper` depending on method you used to install.
You'll be asked to type some random characters that will add entropy to the random number generator. Run with `--help` to see all options
### Saving as PDFs
To generate a Hush paper wallet and save it as a PDF, run:
```
./SilentDragonPaper -z 3 --format pdf sdp.pdf
```
This will generate 3 shielded z-addresses and their corresponding private keys, and save them in a PDF file called `sdp.pdf`
### Vanity Addresses
You can generate a "vanity address" (that is, an address starting with a given prefix) by specifying a `--vanity` argument with the prefix you want.
Note that generating vanity addresses with a prefix longer than 4-5 characters is computationally expensive. You can run it on multiple CPUs on your computer by specifying the `--threads` option.
## Ensuring Security
When generating paper wallets that will store large amounts of crypto, please take special care to ensure the keys are generated and kept completely offline.
1. `SilentDragonPaper` supports ARMv8 (Raspberry Pi 3+). You can put one in a Faraday cage along with a printer, and print out the PDFs securely.
2. Please ensure you supply random entropy when you run `SilentDragonPaper`. Your entropy is mixed in with system-provided entropy to generate keys
3. If you can, run with `unshare`, which will disable all network interfaces to a process, providing you with an additional layer of safety. (See next section)
4. After you've generated the keys, you can tear off the Address potion of the wallet and take it to your online computer/phone to send the address funds. Please always keep the private key offline.
5. When you're ready to spend the cold storage keys, import the private key into a full node, then don't re-use the key again.
### Run without network
If you are running a newish version of Linux, you can be doubly sure that the process is not contacting the network by running SilentDragonPaper without the network namespace.
```
sudo unshare -n ./target/release/SilentDragonPaper
```
`unshare -n` runs the process without a network interface which means you can be sure that your data is not being sent across the network.
## Help options
```
USAGE:
SilentDragonPaper [FLAGS] [OPTIONS] [output]
FLAGS:
-h, --help Prints help information
-n, --nohd Don't reuse HD keys. Normally, SilentDragonPaper will use the same HD key to derive multiple
addresses. This flag will use a new seed for each address
-V, --version Prints version information
OPTIONS:
-e, --entropy Provide additional entropy to the random number generator. Any random string,
containing 32-64 characters
-f, --format What format to generate the output in [default: json] [possible values: pdf, json]
-t, --taddrs Numbe rof T addresses to generate [default: 0]
--threads Number of threads to use for the vanity address generator. Set this to the number of
CPUs you have [default: 1]
--vanity Generate a vanity address with the given prefix.
Note that ['b', 'i', 'o', '1'] are not allowed in addresses.
-z, --zaddrs Number of Z addresses (Sapling) to generate [default: 1]
ARGS: