Here’s how it works:

Every account on the Copper Platform is set up with a Vault. This is where you leave the digital assets you don’t want to trade with in any of the multiple trading accounts you or your team may be operating to buy/sell crypto on the Platform.

In order to withdraw digital assets from the Vault to an external location on the blockchain (ie not one of your trading accounts in the Copper Platform) you will need to authorise the transaction using Copper Unlimited, our standalone secure custody application.

There is no additional cost to this. There are just some additional steps to take, which secure your account better than any other provider on the market. It gives us peace of mind to know your digital assets are secure, even if it means taking a few moments longer to process withdrawals (please note this doesn't effect trading on the Copper Platform).

Read more about encryption and security in our post: Encrypting Crypto

The Copper Unlimited application is divided into two functions: wallet creation and transaction authorisations.

The first time a user interacts with the application, they will receive an activation code and download link from their account in the Copper Platform. From there:

Macos Catalina 10.15.7 Download Dmg Extra Quality < 4K 2027 >

There are two primary ways to obtain the installer. Note that Apple typically distributes the OS as an application bundle ( Install macOS Catalina.app ) rather than a raw DMG file. You generally have to convert the App or create a DMG from the App.

This version includes critical security patches that protect against modern vulnerabilities. Where to Download the macOS Catalina DMG macos catalina 10.15.7 download dmg

⚠️ Avoid random “free DMG download” websites – many bundle adware. Stick to Apple’s official channels or verified Terminal commands. There are two primary ways to obtain the installer

Connect a USB flash drive (at least 16GB) and format it as "Mac OS Extended (Journaled)" with the name MyVolume . This version includes critical security patches that protect

This command downloads the full installer directly from Apple's servers to your /Applications folder. How to Create a Bootable USB from the DMG

If you need a clean copy of macOS Catalina 10.15.7 to create a bootable USB, perform a fresh install on an older Mac, or keep as an offline backup, the official DMG file is your best option.

Visit Apple’s “How to get old versions of macOS” support article. From there, you’ll be redirected to the App Store, where the Catalina installer downloads as an app – not directly as a DMG. However, once downloaded (about 8 GB), you can right-click the installer package and select Show Package Contents → Contents → SharedSupport to extract the actual DMG installer.

If the user already has a wallet set up, or if they are a key holder and have just received a notification, then the process for transaction authorisation is as follows:

1. On the application home screen, the user selects the second option for Co-signing.
2. The user will then be prompted to upload their distributed key file and enter the password for their distributed key. This password was set by the account owner and will have been sent to the user when the distributed key was created.
3. The Copper Unlimited application will show the transaction details and ask for them to be verified as correct.
4. Once the key holder is satisfied that the details are correct they will click the confirmation button.
5. Once the Copper Unlimited application has received transaction authorisations from two out of three key holders it will broadcast the transaction to the blockchain.

Copper now supports Optical Air-Gapping for signing transactions

Why is this better, it sounds harder?

Distributed keys mean that even if you lose yours, having nominated three key holders (your solicitor and two colleagues, for example), a transaction can still be authorised. This would enable you to set up a new wallet, transfer all assets out of the old one into the new one, and this time be a little more careful with the password, should it slip your mind the first time.

The Copper Unlimited application provides additional security, additional accountability through co-signing, and additional protection from human error in the form of distributed keys. It is also the only blockchain agnostic custody solution you will find.

For more information on how your organisation can benefit from Copper Unlimited, please send an enquiry to our .

To learn more about how Optical Air-Gapping makes signing transactions offline even safer, read this article.