016da1138f2ba94fb7b7bb37ccd915846c62fb1f995437b28e95ed3b48733c2d

Here the step-by-step procedure for the independent verification of the data or document notarization :

This is a courtesy page provided by Quadrans Foundation for convenience to easier proove the correct notarization of the submitted data hash.
This is a free service, as such Quadrans cannot be held responsible for any loss or damage.
Please print or save this page and store it in a safe place for later reference and use.
With those it's easy to proove ownership, timestamping, time of existence, consistency and immutability of data.

It is necessary to:

• store the original data at the time of this notarization
• store this page with the notarization data

Quadrans will not store any of those. No guaranties are provided that this page will still be available at any time in the future.
Therefore the owner of the data and email address is responsible for the storage of both.

All the following steps make extensive use of the cryptographic hash function (SHA256) on binary bytes strings, here represented in their exadecimal notation.

1) Getting to the evidence

The evidence is the double hash of the concatenation of 2 binary hashes of data available to the sender:

• the hash of the original data/document and
• the hash of email address thar the sender used

Using any Linux console, it is possible to check the evidence using the hash submitted for the data [hd] and the hash of the email address [he] used with:

echo -n [hd][he] | tr "[:lower:]" "[:upper:]" | xxd -r -p | sha256sum | xxd -r -p | sha256sum

According to the properties of cryptographic hash functions, excluding the extremelly unlikely event of collisions, that evidence can only result as hash of the to previously provided elements.

2) Merkle Proof

The evidence is stored with many others into a covenient data structure called Merkle Tree. All those evidences are coupled and hashed together in a binary tree until a single hash can be derived, called Merkle Root.
In order to proove matematically that an evidence is part of a merkle tree, a list of the other hashes (called Merkle Proof) must be provided, and those have to be hashed together and result in the same Merkle Root.

For this particular evidence the list of hashes is :

513caa4ec41bbb5acaba9144737425b7b78f92de8e0cf82b5039bad39110f715 (your data)
016da1138f2ba94fb7b7bb37ccd915846c62fb1f995437b28e95ed3b48733c2d (your evidence)
016da1138f2ba94fb7b7bb37ccd915846c62fb1f995437b28e95ed3b48733c2d (merkle tree root)

3) Merkle Tree

The correct combination of those hashes to get to the Merkle Root is:

016da1138f2ba94fb7b7bb37ccd915846c62fb1f995437b28e95ed3b48733c2d (calculated root)

This clearly shows :

• the Merkle Root (in bold) as calculated by the other hashes in the proof
• the data evidence value (in bold) as described in Point 1
• the other proof hashes (in italic)
• the combination of the other hashes (calculated from previous hashes)

Those hashes are calculated on binary numeric values (byte arrays). Using any Linux console it is possible to check each pair of hashes [h1] and [h2] with:

echo -n [h1][h2] | tr "[:lower:]" "[:upper:]" | xxd -r -p | sha256sum

This proves that the evidence 016da1138f2ba94fb7b7bb37ccd915846c62fb1f995437b28e95ed3b48733c2d is part of the merkle root 016da1138f2ba94fb7b7bb37ccd915846c62fb1f995437b28e95ed3b48733c2d

4) Blockchain Notarization

Provided that the evidence is part of the merkle root, that specific value has been notarized in the Quadrans blockchain in this position and date:

It is possible to use Quadrans Explorer to see that transaction and inspect it's content. The relevant data are stored in the transaction's event logs.

5) Transaction Analysis

With the merkle tree and the transaction it was recorded in, it is possible to use web3 api to get the transaction receipt.
It is necessary to have the smart contract ABI. Sample code for this operation is provided in python and javascript.
It is also necessary to have access to a free Quadrans Node.

Running that procedure the result is the following:

The recorded "_hash" value matches the merkle root, this shows that the all the evidences, with the provided merkle proof, where successfully notarized on the Quadrans blockchain.

Don't trust, verify.