veracity

Veracity is a command line tool providing support for inspecting the DataTrails native MERKLE_LOG verifiable data structures.

A general familiarity with verifiable data structures, and in particular binary merkle trees, would be advantageous, but is not required.

Installation

Veracity provides native binaries for Mac OS, Linux on the releases page.

Note: For The Windows Subsystem for Linux (WSL), use the Linux binaries.

1. Select the desired release from the releases page.
2. Download the archive for your host platform
3. Extract the archive
4. Set the file permissions
5. Move the binary to a location on your PATH

Or, follow these commands to install the latest build.

Mac Install

PLATFORM=$(uname -s | tr [:upper:] [:lower:])
ARCH=$(uname -m)
cd $TMPDIR
curl -sLO https://github.com/datatrails/veracity/releases/latest/download/veracity_${PLATFORM}_${ARCH}.tar.gz
tar -xf veracity_${PLATFORM}_${ARCH}.tar.gz
chmod +x ./veracity
mv ./veracity $HOME/.local/bin/
veracity --help

Linux/WSL Install

PLATFORM=$(uname -s | tr [:upper:] [:lower:])
ARCH=$(uname -m)
cd /tmp
curl -sLO https://github.com/datatrails/veracity/releases/latest/download/veracity_${PLATFORM}_${ARCH}.tar.gz
tar -xf veracity_${PLATFORM}_${ARCH}.tar.gz
chmod +x ./veracity
mv ./veracity $HOME/.local/bin/
veracity --help

Troubleshooting

If veracity --help fails, check the following:

Confirm $PATH includes .local/bin. Either add the location to $PATH, or place veracity in an alternate location within an existing $PATH.

# Check veracity exists in your $PATH
echo $PATH

# Add to the path
export PATH="$HOME/.local/bin:$PATH"
# reload the configuration
source ~/.bashrc

# Confirm which veracity binary is being used
which veracity

Example Usage

Environment Variables

The following samples use environment variables to simplify the commands:

EVENT_ID=publicassets/87dd2e5a-42b4-49a5-8693-97f40a5af7f8/events/a022f458-8e55-4d63-a200-4172a42fc2aa
DATATRAILS_URL=https://app.datatrails.ai
PUBLIC_TENANT_ID=tenant/6ea5cd00-c711-3649-6914-7b125928bbb4

Verifying A Single Event

The following steps verify the single public event a022f458-8e55-4d63-a200-4172a42fc2aa using the DataTrails API.

Check the event details directly.

1. Download the event from the DataTrails ledger:

   curl -sL $DATATRAILS_URL/archivist/v2/$EVENT_ID > event.json
   

2. Verify inclusion with veracity

   cat event.json | \
       veracity --data-url $DATATRAILS_URL/verifiabledata \
       --tenant=$PUBLIC_TENANT_ID \
       --loglevel=INFO \
       verify-included
   

3. View the output, noting there are no verification errors

   verifying for tenant: tenant/6ea5cd00-c711-3649-6914-7b125928bbb4
   verifying: 663 334 018fa97ef269039b00 2024-05-24T08:27:00.2+01:00 
   publicassets/87dd2e5a-42b4-49a5-8693-97f40a5af7f8/events/a022f458-8e55-4d63-a200-4172a42fc2aa
   leaf hash: bfc511ab1b880b24bb2358e07472e3383cdeddfbc4de9d66d652197dfb2b6633
   OK|663 334|[aea799fb2a8..., proof path nodes, ...f0a52d2256c235]
   

Note: To minimize veracity output, remove --loglevel, checking the exit code of 0 (echo $?) for a successful verification.

The elided proof path at time of writing was:

[aea799fb2a8c4bbb6eda1dd2c1e69f8807b9b06deeaf51b9e0287492cefd8e4c,
9f0183c7f79fd81966e104520af0f90c8447f1a73d4e38e7f2f23a0602ceb617, 
a21cb383d63896a9811f06ebd2094921581d8eb72f7fbef566b730958dc35f1, 
1ea08fd02da3633b72ef0b09d8ba4209db1092d22367ef565f35e0afd4b0fc3, 
85a9d55cf507ef85bd264f4db7228e225032c48da689aa8597e11059f45ab30, 
ab40107f7d7bebfe30c9cea4772f9eb3115cae1f801adab318f90fcdc204bdc, 
4ca607094ead6fcd23f52851c8cdd8c6f0e2abde20dca19ba5abc8aff70d0d1, 
a6d0fd8922342aafbba6073c5510103b077a7de9cb2d72fb652510110250f9e, 
fafc7edc434225afffc19b0582efa2a71b06a2d035358356df0a52d2256c235, 
737375d837e67ee7bce182377304e889187ef0f335952174cb5bf707a0b4788]

Verify Tamper Resiliency

One of the many scenarios DataTrails prevents is tampering if and when information was written to the ledger.

1. To simulate backdating, the following backdates one of the events in the log:

   sed -i -e 's/2024-05-24T07:27:00.200Z/2024-04-24T07:27:00.200Z/g' ./event.json
   

2. Re-verify inclusion with veracity verify-included, noting the error

   cat event.json | \
       veracity --data-url $DATATRAILS_URL/verifiabledata \
       --tenant=$PUBLIC_TENANT_ID \
       --loglevel=INFO \
       verify-included
   

3. View the output

   ...
   error: the entry is not in the log. for tenant tenant/6ea5cd00-c711-3649-6914-7b125928bbb4
   

Verify All Events

The veracity verify-included command accepts the result of a DataTrails list events call. This verifies the inclusion of each event in the returned list.

1. Pipe the events to veracity:

   PUBLIC_ASSET_ID=publicassets/87dd2e5a-42b4-49a5-8693-97f40a5af7f8
   curl -sL $DATATRAILS_URL/archivist/v2/$PUBLIC_ASSET_ID/events | \
       veracity --data-url $DATATRAILS_URL/verifiabledata \
           --tenant=$PUBLIC_TENANT_ID \
           --loglevel=INFO \
           verify-included 
   

Read a Selected Node From the Log

An example of reading a node associated with event, it's possible to visit merkle log entry page for event 999773ed-cc92-4d9c-863f-b418418705ea

On the Merkle log entry page we can see the MMR Index field with a value of 916 which can be used with the node command to retrieve the leaf directly from the merklelog using following command:

veracity --data-url $DATATRAILS_URL/verifiabledata \
    --tenant=$PUBLIC_TENANT_ID \
    node --mmrindex 916

The above command will output c3323019fd1d325ac068d203c62007b504c5fa762446a9fe5d88e392ec96914b which will match the value from the merkle log entry page.

General Use Commands

Additional Commands include:

• node - read a merklelog node
• verify-included - verify the inclusion of an event, or list of events, in the tenant's merkle log
• watch - discover recently active logs
• replicate-logs - create or update a local trusted replica of one more more tenants logs, accepts the output of watch as input.
• receipt - Generate a COSE Receipt of inclusion using the MMRIVER profile for an entry.

For more information, please visit the DataTrails documentation