Centralized SSI Ledger

This is an implementation of a basic Centralized SSI Ledger. It can be run with aries-cloudagent-python and it has been tested and used with the indy wallet.

Table of contents

• Dependencies
• How to build libindy
• How to build
  • Build on Linux
  • Build on macOS
• How to run
  • Run on Linux
  • Run on macOS
• macOS troubleshooting
  • OpenSSL error
  • libindy not found

Dependencies

All the project dependencies are automatically handled with maven except for the libindy native library, which you must compile on your machine in order to let this ledger run correctly. Despite the libindy dependency, this ledger is not indy-based: indeed libindy is used only to allow the generation of a keypair from a seed.

If you have not compiled this library on your machine yet, please refer to the How to build libindy section.

How to build libindy

As first step, we need to compile the libindy library. To do it, you must clone the indy-sdk repository on your machine. Once you have cloned the repository, install the sdk referring to the How to build Indy SDK from source section.

In the next sections we refer the location where you have cloned the indy-sdk repository as <indy-sdk-folder>.

How to build

Build on linux

To build this project, run from the root of this project the command:

$ LD_LIBRARY_PATH=<indy-sdk-folder>/libindy/target/debug mvn clean install

Build on macOS

To build this project, run from the root of this project the command:

$ DYLD_LIBRARY_PATH=<indy-sdk-folder>/libindy/target/debug mvn clean install

How to run

If the build was successful, you should have a .jar archive built under the ./target folder.

Run on linux

To start the centralized ledger, run the command:

$ LD_LIBRARY_PATH=<indy-sdk-folder>/libindy/target/debug java -jar centralizedledger-0.0.1-SNAPSHOT.jar

Run on macOS

To start the centralized ledger, run the command:

$ DYLD_LIBRARY_PATH=<indy-sdk-folder>/libindy/target/debug java -jar centralizedledger-0.0.1-SNAPSHOT.jar

macOS troubleshooting

Here a quick guide to solve some errors you could encounter when following the guide above.

OpenSSL error

If you get an error regarding the OpenSSL package when you build the library libindy with the cargo build command, this may be related to the wrong definition of the OPENSSL_DIR environment variable. At the time of writing, libindy is compatible with [email protected], but not with openssl@3. Make sure that OPENSSL_DIR points to the former version:

$ export OPENSSL_DIR=/usr/local/Cellar/[email protected]/1.1.1o

libindy not found

When we build and run this ledger, we must be able to manipulate the DYLD_LIBRARY_PATH environment variable on macOS in order to allow java to find and use the libindy library. On recent macOS versions the manipulation of DYLD_LIBRARY_PATH could be prevented by the System Integrity Protection (aka SIP) feature, which prevents users from changing a bunch of environment variables for all the binaries located in some specific filesystem locations (e.g. all the binaries under the folder /usr). If SIP is enabled on your machine and your mvn and java binaries are located under one of the protected folders, you cannot change the value of DYLD_LIBRARY_PATH.

To check if SIP is enabled on your machine, run:

$ csrutil status

To check the location of your java binary run the command:

$ which java

If SIP is enabled on your machine and your mvn and java binaries are located under one of the protected folders, you cannot change the value of DYLD_LIBRARY_PATH. To solve this problem you either need to disable SIP on your macOS (see here) or use java and mvn binaries located outside the /usr folder.