Provable Solvency Report #66 – September 2019

Coinfloor is a custodian of client bitcoins and we believe that we must set the industry standard for transparency and regular audits. Without proper public accountability, the industry will not be able to grow and mature. This is why we are committed to releasing a
Provable Solvency Report every month. Coinfloor is proud to have the longest standing track record among bitcoin exchanges in regards to auditing.

Today we are publishing our 66th monthly Provable Solvency Report with step-by-step
validation instructions for your convenience.

As of today, Coinfloor holds a total of
3,907.8566 XBT on behalf of our clients. You are invited to verify that your held bitcoins are included in this balance by following the instructions below.

What does the Provable Solvency Report include?

We started out by creating an obfuscated report of all current client balances (the Solvency Report) and then generated a
SHA-256 hash of this report.

We then created a bitcoin transaction to ourselves, that includes all currently held client bitcoins, for a value of
3,944.0563 XBT. The output of the script also includes the
OP_RETURN of the SHA-256 hash of the report, proving that at the time of making the solvency report, Coinfloor held all of our clients’ XBT funds. You can
verify the amount and details of the transaction on the blockchain.

Key Pieces of information:


Provable Solvency Report #66 (September 30th, 2019):

https://s3-eu-west-1.amazonaws.com/provablesolvency/solvency_20190930.txt

SHA-256 Hash of the Provable Solvency Report: 0F7C866DC215B965067F7E01828696216F19141CA11638AD21C7272E1879404C

Transaction ID: 737282fa27d66208b53541a78b7c9a31c8e7bd7a8d52ad87de2498421ce0ea95

View the transaction here:

https://explorer.bitcoin.com/btc/tx/737282fa27d66208b53541a78b7c9a31c8e7bd7a8d52ad87de2498421ce0ea95

Your API authentication cookie:

You will find it in My Account > Dashboard in the Coinfloor signed in view, in the API section (visible only for fully verified accounts).

Instructions for Validating Solvency Report:

1. Open the Provable Solvency Report file:

https://s3-eu-west-1.amazonaws.com/provablesolvency/solvency_20190930.txt

2. Go to

https://passwordsgenerator.net/sha256-hash-generator/ or to your SHA256sum calculating application.

Copy the entire contents of the solvency report (including any leading or trailing spaces or blank lines) into the SHA-256 generator and calculate the SHA-256 hash of the report.

3. Go to

https://explorer.bitcoin.com/btc/tx/737282fa27d66208b53541a78b7c9a31c8e7bd7a8d52ad87de2498421ce0ea95

Click on the `SHOW ADVANCED` switch to view the OP_RETURN, where you will find the hash generated in the previous step matches the hash in the OP_RETURN output script of the transaction that includes all customer bitcoins.

Instructions for finding your account balance within the Solvency Report:

1. Go to

your local SHA1sum application

to calculate the SHA-1 digest of a message consisting of the timestamp shown at the top of the Solvency Report (1569839219) and your API authentication cookie.

Example (Linux):

    timestamp: 1569839219

    API authentication cookie (API Key): 9BTa7M0Z/Mrk6tFMJwEkTV3BQek=

    command: echo -n ‘15698392199BTa7M0Z/Mrk6tFMJwEkTV3BQek=’ | sha1sum

(the command may differ depending on the SHA1sum application used)

2. Find the resulting hash in the solvency report. Your balance is shown on that line in satoshi units. 1 bitcoin = 100 000 000 satoshis. For your convenience, here is a link to a bitcoin unit converter:

http://www.satoshi.24ex.com

We believe that this approach is the best way to achieve maximum accountability whilst retaining privacy for our clients. We welcome your feedback and hope that in time, other exchanges will also help safeguard client funds by providing proof of solvency reports to their users on a regular basis.

Thank you for your trust,

Coinfloor Team

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