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## Initializing the signer
First, initialize the master seed.
```text
#./signer init
WARNING!
The signer is alpha software, and not yet publically released. This software has _not_ been audited, and there
are no guarantees about the workings of this software. It may contain severe flaws. You should not use this software
unless you agree to take full responsibility for doing so, and know what you are doing.
TLDR; THIS IS NOT PRODUCTION-READY SOFTWARE!
Enter 'ok' to proceed:
>ok
A master seed has been generated into /home/martin/.signer/secrets.dat
This is required to be able to store credentials, such as :
* Passwords for keystores (used by rule engine)
* Storage for javascript rules
* Hash of rule-file
You should treat that file with utmost secrecy, and make a backup of it.
NOTE: This file does not contain your accounts. Those need to be backed up separately!
```
(for readability purposes, we'll remove the WARNING printout in the rest of this document)
## Creating rules
Now, you can create a rule-file. Note that it is not mandatory to use predefined rules, but it's really handy.
```javascript
function ApproveListing(){
return "Approve"
}
```
Get the `sha256` hash. If you have openssl, you can do `openssl sha256 rules.js`...
```text
#sha256sum rules.js
6c21d1737429d6d4f2e55146da0797782f3c0a0355227f19d702df377c165d72 rules.js
```
...now `attest` the file...
```text
#./signer attest 6c21d1737429d6d4f2e55146da0797782f3c0a0355227f19d702df377c165d72
INFO [02-21|12:14:38] Ruleset attestation updated sha256=6c21d1737429d6d4f2e55146da0797782f3c0a0355227f19d702df377c165d72
```
...and (this is required only for non-production versions) load a mock-up `4byte.json` by copying the file from the source to your current working directory:
```text
#cp $GOPATH/src/github.com/ethereum/go-ethereum/cmd/clef/4byte.json $PWD
```
At this point, we can start the signer with the rule-file:
```text
#./signer --rules rules.js --rpc
INFO [09-25|20:28:11.866] Using CLI as UI-channel
INFO [09-25|20:28:11.876] Loaded 4byte db signatures=5509 file=./4byte.json
INFO [09-25|20:28:11.877] Rule engine configured file=./rules.js
DEBUG[09-25|20:28:11.877] FS scan times list=100.781µs set=13.253µs diff=5.761µs
DEBUG[09-25|20:28:11.884] Ledger support enabled
DEBUG[09-25|20:28:11.888] Trezor support enabled
INFO [09-25|20:28:11.888] Audit logs configured file=audit.log
DEBUG[09-25|20:28:11.888] HTTP registered namespace=account
INFO [09-25|20:28:11.890] HTTP endpoint opened url=http://localhost:8550
DEBUG[09-25|20:28:11.890] IPC registered namespace=account
INFO [09-25|20:28:11.890] IPC endpoint opened url=<nil>
------- Signer info -------
* extapi_version : 2.0.0
* intapi_version : 2.0.0
* extapi_http : http://localhost:8550
* extapi_ipc : <nil>
```
Any list-requests will now be auto-approved by our rule-file.
## Under the hood
While doing the operations above, these files have been created:
```text
#ls -laR ~/.signer/
/home/martin/.signer/:
total 16
drwx------ 3 martin martin 4096 feb 21 12:14 .
drwxr-xr-x 71 martin martin 4096 feb 21 12:12 ..
drwx------ 2 martin martin 4096 feb 21 12:14 43f73718397aa54d1b22
-rwx------ 1 martin martin 256 feb 21 12:12 secrets.dat
/home/martin/.signer/43f73718397aa54d1b22:
total 12
drwx------ 2 martin martin 4096 feb 21 12:14 .
drwx------ 3 martin martin 4096 feb 21 12:14 ..
-rw------- 1 martin martin 159 feb 21 12:14 config.json
#cat /home/martin/.signer/43f73718397aa54d1b22/config.json
{"ruleset_sha256":{"iv":"6v4W4tfJxj3zZFbl","c":"6dt5RTDiTq93yh1qDEjpsat/tsKG7cb+vr3sza26IPL2fvsQ6ZoqFx++CPUa8yy6fD9Bbq41L01ehkKHTG3pOAeqTW6zc/+t0wv3AB6xPmU="}}
```
In `~/.signer`, the `secrets.dat` file was created, containing the `master_seed`.
The `master_seed` was then used to derive a few other things:
- `vault_location` : in this case `43f73718397aa54d1b22` .
- Thus, if you use a different `master_seed`, another `vault_location` will be used that does not conflict with each other.
- Example: `signer --signersecret /path/to/afile ...`
- `config.json` which is the encrypted key/value storage for configuration data, containing the key `ruleset_sha256`.
## Adding credentials
In order to make more useful rules like signing transactions, the signer needs access to the passwords needed to unlock keystores.
```text
#./signer addpw "0x694267f14675d7e1b9494fd8d72fefe1755710fa" "test_password"
INFO [02-21|13:43:21] Credential store updated key=0x694267f14675d7e1b9494fd8d72fefe1755710fa
```
## More advanced rules
Now let's update the rules to make use of credentials:
```javascript
function ApproveListing(){
return "Approve"
}
function ApproveSignData(r){
if( r.address.toLowerCase() == "0x694267f14675d7e1b9494fd8d72fefe1755710fa")
{
if(r.message.indexOf("bazonk") >= 0){
return "Approve"
}
return "Reject"
}
// Otherwise goes to manual processing
}
```
In this example:
* Any requests to sign data with the account `0x694...` will be
* auto-approved if the message contains with `bazonk`
* auto-rejected if it does not.
* Any other signing-requests will be passed along for manual approve/reject.
_Note: make sure that `0x694...` is an account you have access to. You can create it either via the clef or the traditional account cli tool. If the latter was chosen, make sure both clef and geth use the same keystore by specifing `--keystore path/to/your/keystore` when running clef._
Attest the new file...
```text
#sha256sum rules.js
2a0cb661dacfc804b6e95d935d813fd17c0997a7170e4092ffbc34ca976acd9f rules.js
#./signer attest 2a0cb661dacfc804b6e95d935d813fd17c0997a7170e4092ffbc34ca976acd9f
INFO [02-21|14:36:30] Ruleset attestation updated sha256=2a0cb661dacfc804b6e95d935d813fd17c0997a7170e4092ffbc34ca976acd9f
```
And start the signer:
```
#./signer --rules rules.js --rpc
INFO [09-25|21:02:16.450] Using CLI as UI-channel
INFO [09-25|21:02:16.466] Loaded 4byte db signatures=5509 file=./4byte.json
INFO [09-25|21:02:16.467] Rule engine configured file=./rules.js
DEBUG[09-25|21:02:16.468] FS scan times list=1.45262ms set=21.926µs diff=6.944µs
DEBUG[09-25|21:02:16.473] Ledger support enabled
DEBUG[09-25|21:02:16.475] Trezor support enabled
INFO [09-25|21:02:16.476] Audit logs configured file=audit.log
DEBUG[09-25|21:02:16.476] HTTP registered namespace=account
INFO [09-25|21:02:16.478] HTTP endpoint opened url=http://localhost:8550
DEBUG[09-25|21:02:16.478] IPC registered namespace=account
INFO [09-25|21:02:16.478] IPC endpoint opened url=<nil>
------- Signer info -------
* extapi_version : 2.0.0
* intapi_version : 2.0.0
* extapi_http : http://localhost:8550
* extapi_ipc : <nil>
```
And then test signing, once with `bazonk` and once without:
```
#curl -H "Content-Type: application/json" -X POST --data "{\"jsonrpc\":\"2.0\",\"method\":\"account_sign\",\"params\":[\"0x694267f14675d7e1b9494fd8d72fefe1755710fa\",\"0x$(xxd -pu <<< ' bazonk baz gaz')\"],\"id\":67}" http://localhost:8550/
{"jsonrpc":"2.0","id":67,"result":"0x93e6161840c3ae1efc26dc68dedab6e8fc233bb3fefa1b4645dbf6609b93dace160572ea4ab33240256bb6d3dadb60dcd9c515d6374d3cf614ee897408d41d541c"}
#curl -H "Content-Type: application/json" -X POST --data "{\"jsonrpc\":\"2.0\",\"method\":\"account_sign\",\"params\":[\"0x694267f14675d7e1b9494fd8d72fefe1755710fa\",\"0x$(xxd -pu <<< ' bonk baz gaz')\"],\"id\":67}" http://localhost:8550/
{"jsonrpc":"2.0","id":67,"error":{"code":-32000,"message":"Request denied"}}
```
Meanwhile, in the signer output:
```text
INFO [02-21|14:42:41] Op approved
INFO [02-21|14:42:56] Op rejected
```
The signer also stores all traffic over the external API in a log file. The last 4 lines shows the two requests and their responses:
```text
#tail -n 4 audit.log
t=2018-02-21T14:42:41+0100 lvl=info msg=Sign api=signer type=request metadata="{\"remote\":\"127.0.0.1:49706\",\"local\":\"localhost:8550\",\"scheme\":\"HTTP/1.1\"}" addr="0x694267f14675d7e1b9494fd8d72fefe1755710fa [chksum INVALID]" data=202062617a6f6e6b2062617a2067617a0a
t=2018-02-21T14:42:42+0100 lvl=info msg=Sign api=signer type=response data=93e6161840c3ae1efc26dc68dedab6e8fc233bb3fefa1b4645dbf6609b93dace160572ea4ab33240256bb6d3dadb60dcd9c515d6374d3cf614ee897408d41d541c error=nil
t=2018-02-21T14:42:56+0100 lvl=info msg=Sign api=signer type=request metadata="{\"remote\":\"127.0.0.1:49708\",\"local\":\"localhost:8550\",\"scheme\":\"HTTP/1.1\"}" addr="0x694267f14675d7e1b9494fd8d72fefe1755710fa [chksum INVALID]" data=2020626f6e6b2062617a2067617a0a
t=2018-02-21T14:42:56+0100 lvl=info msg=Sign api=signer type=response data= error="Request denied"
```
|
