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Dedicated Monero Hardware Wallet

Version: 1.0
Date: 15 September 2017
Author: Michael Schloh von Bennewitz
Contact: [email protected]
IRC-contacts: msvb-lab, msvb-mob
Title: Dedicated Monero Hardware Wallet

Get Monero Hardware Wallets

"There are currently no hardware wallets available at this time. Please check back for updates."
-, August 2017

It's time for the Monero community to come together and realize the goal of a hardware wallet!


The status of this proposal is:


Change Log

In reverse cron order.

20170915  Publish version 1.0
          Added sketchy RF integration
          Explained schedule of procurement
          Clarified work to reverse engineer
          Mentioned possible Shmoocon promotion
          Removed nonhardware based requirements
          Detailed role of microscopy in workflow
          Included more secure element details
          Zero sum corrected budget for lab
          Added plan column for FFS release

20170913  Publish version 0.9
          Added copyright statement
          Added airgap feature option
          Clarified choice of License
          Slight changes to the budget
          Slight changes to requirements
          Added related project content
          New Defunding Option section
          New Proposal Ownership section
          New Legal Summary section
          New requested Intention section
          Documented outreach to Gemalto
          Emphasized hardware focus and license

20170912  Publish version 0.8
          Nonfunctional Requirements additions
          Requirements 'note' reminder
          Time floor function removed
          Secure Element development
          New Scope Creep section
          Project plan adjustment
          Budget detailed design
          XMR rate changed to 67
          Workflow development

20170830  Publish version 0.7
          Functional Requirements additions
          Budget clarification
          New Workflow section

20170818  Publish revision 0.6

20170816  Proposal creation

20170801  DefCon Genesis

Monero Hardware Wallet


Note: PLEASE REMEMBER THAT THE DELIVERABLE (SEE SECTIONS 'DELIVERABLES' AND 'SCOPE CREEP') IS A PRINTED CIRCUIT BOARD DESIGN. Other efforts exist to produce related deliverables like bootloader, firmware, enclosures, branding, modding, and derivatives.

Nonfunctional Requirements

  • Quality: The project is bodacious (bold and audacious)
  • Usability: Simple and intuitive, one hour learning time
  • Availability: Build your own and commercial models supported
  • Accessibility: One (of two total) button operation
  • Verification: Standard on board private display
  • Legal clarity: Avoidance of NDA and closed source terms
  • Legal freedom: Patent treaty via Open Invention Network
  • Open natured: All assembled parts ship with datasheets
  • Regulatory compliance: Attention to RoHS certification
  • Invulnerability: Prohibitive intrusion effort or time
  • Data integrity: Selective verification by SE cryptoanalysis
  • Reliability: MTBF to be determined and documented
  • Operating constraints: High firmware compatibility
  • Size constraints: To be determined after enclosure research
  • Resilience: Broad degree (voltage and temperature) of operation
  • Interoperability: Provision to interface with software wallets
  • Capacity: Balance between feature storage size and transistor constraint
  • Supportability: Supported through existing (forum, IRC, Reddit) channels
  • Privacy: Timer equipped for dimming, and narrow viewing angle
  • Documentation: Camera ready collection of developer documents
  • HW testability: Unpopulated debug (JTAG or similar) headers
  • FW testability: Bootloader and sample firmware templates
  • Extensibility: Open design with a common EDA CAD application
  • Marketability: Support for product design and management efforts
  • Derivability: Variation by unpopulating an overextended design
  • Portability: Portions of design forked from other projects

Functional Requirements

  • Power supply
    • 5V USB connection
    • 3V3 Battery housing
  • Security design criteria
    • Crypto: Private key in secure element¹
    • Potting: Epoxy compound (optional²)
    • Production: Non-RST debug removal
    • Airgap: Disconnected media option³
  • CPA and glitch defense
    • Dual MCU comparison circuit⁴
    • ...or external secure element⁴
  • Invasive border search protection
    • Passphrase plausible deniability
    • 48V supercap discharge circuit
    • ...or puncture destruction kit⁵
  • Intrusion detection criteria⁶
    • Ambient light interruption
    • Mechanical switch interruption
  • Physical stability
    • High rated semiconductors
    • Moisture ingress nanocoating
  • Developer friendliness
    • Development: JTAG breakout
    • Pogo pin harness option
  • User friendliness
    • Replaceable battery
    • Replaceable optional media⁴
    • Screen sized to allow QR
    • Possible RF integration³
      ...unless we want to avoid BlueBorne

¹ Depending on availability of supporting IC
² How to apply potting is documentation only
³ Research prone feature, may yield suboptimal
⁴ Depending on results of cost and size analysis
⁵ Destruction by puncture is documentation only
⁶ Independent circuit for optional model extension

Secure Element

A secure element (SE) serves to verify firmware at boot via standard DSA or ECDSA, and hopefully a vendor of hardware key storage is found that supports Monero's ED25519 elliptic curve. A private key in a real (with lock features) secure element means that even rogue firmware cannot access the key.

It seems this would be the first design to ever implement such a high degree of wallet security, but unfortunately ECDSA support depends on the hardware vendor. This is a formidable challenge.

Degree of Success

Several weeks of research will determine which of the desired secure element supported implementations are realistic. A worst case scenario is that ED25519 is completely unsupported and must be processed by firmware in SRAM, the same thing that Ledger and Trezor do. Preliminary research suggests the possibility that ARM CryptoCell circuits support hardware ED25519 calculations with a unknown (possibly no locking supported) key deployment method.

Vendor Proposal

Discussion (even before this proposal concludes) is ongoing with Microchip, Atmel, and Gemalto. We want them to produce integrated circuits according to the very easy to meet requirements.

Other Requirements

  • Review of requirements from the existing designs of Ledger, Trezor, and KeepKey
  • Blend of features from peripheral devices like Opendime, Mooltipass, and Cryptosteel


The Monero hardware wallet is a printed circuit board design resembling the Ledger or Trezor wallet PCBs. It may be slightly larger in size and composed of fewer (broader reach) or more (optimal electronic density) substrate layers.

Please see related RFC-HWALLET-X proposals for product design, firmware implementation, and other non hardware design work.

Scope Creep

The project is particularly vulnerable to scope creep. Votes or attempts at consensus on how to react to changing requirements are not planned. Rather, a compromise (maintaining pace of progress) is reached by attending nearly all Monero development meetings and reporting accordingly.

If contributors are interested in applied agile methods to track scope, then this can be arranged once agreement is reached in meetings.


Michael is a computer scientist undergraduate with 15 years of industry (software, telecom, embedded systems) experience. He trains groups at Black Hat [1] and produces (not for sale) hardware in his circuits lab. He worked with the inventor of mod_ssl at Cable & Wireless, collaborates with WolfSSL on Atmel/Microchip IC to low powered ESP8266 platform porting, as well as MbedTLS on Atmel secure element provisioning.

He is a cryptocurrency novice of Ethereum, Bitcoin, and now Monero. He has earned the trust of his students using custom derivatives of Bus Pirate, FRDM, and NodeMCU shield devices, as well as larger companies (references on request) assigning first generation SBC hardware shield extensions on contract.



If you look carefully, you will find the privacy sensitive software development Michael has done for high profile groups.


Michael is motivated to complete this project in order to have a Monero hardware wallet of his own, improve PCB design skills using a secure element, contribute to Monero enthusiasm, and become more active in the Monero community (by owning coins and IRC communicating frequently.)


If all related FFS proposals are rejected, then Michael will probably be a Monero currency owner but cannot afford to contribute software, firmware, or hardware logic.


Portions of the production machinery budget may be defunded, leading to the following added risk:

  • Unexpected scope reverse creep
  • Loss of miniaturization requirements
  • Loss of component choice requirements
  • Reduction or cancellation of samples distribution
  • Reduction or cancellation of promotion deliveries
  • Fewer test generations leading to reduced QA work
  • Introduction of new budget items to fund assembly
  • Failure of any process requiring quick or accurate manufacturing

The actions and features at risk would still be worked on a best effort basis. To be clear, this proposal has no defunded budget items and production machinery will be procured in the most expedient and inexpensive way.


Some RFC-HWALLET-X proposals are complementary and others mutually exclusive. In the best case, this pilot project will serve to launch and support other (conference badge, sponsored swag, product integrations, university research) related projects.


Production machinery

XMR Item
5 Qinsi QS-5100 reflow oven
45 Analog stereo microscope
150 NeoDen4 Pick and Place
200 Total machinery

Research equipment

XMR Item
1 Trezor
1 KeepKey
4 Ledgers
6 Chipwhisp
2 Launchpad
<1 Opendime
15 Total research

Passive and IC components

XMR Item
20 Total components

Consumable materials

XMR Item
25 Paste, substrate, nozzles

Facilities and services

XMR Item
2 Makerspace entry
68 Workspace rental
12 Datacenter, telco
80 Total facilities

Travel and promotion

XMR Item
0 Included in other items

Trips to manufacturing locations (Shenzhen or Hangzhou) will not be taken unless necessary, for example when a flight is cheaper than postal shipping or acting as a courier yields a customs free import. In those cases, trip cost is absorbed by the budget stated resource price (with nothing new to add.)

Worktime reimbursement

XMR Item
490 Lost contracts reimbursement⁷

⁷ Estimated by crossing vectors (6 months lapse, proximity obligation, hour loss) and considering used nonworktime procurements.

XMR Volatility

A 20% buffer is in place to lower risk of production loss or delay. This is partly due to Michael's lack of crypto trading experience and partly due to natural monetary fluctuation.

Total budget

XMR Item
996 Fulfillment of requirements

Note: The base rate is recalculated (95 € + 40 €) ÷ 2 resulting in 1XMR = 67EUR €. The previous base rate was 40EUR € before fluctuation and the current price is 80EUR €.

Existing Resources

A number of machines is already available including a Voltera V-One substrate printing machine, JND-983A solder dispenser, industrial air compressor, dedicated circuit production computer, and solder rework station.

The total value of already acquired machinery is estimated at 8000EUR € (120XMR.) These resources will be used but require no budget.

Nonexistent Resources

Any tools needed (see 'Production machinery') should be purchased in the first month (see 'Project Plan'), in order to avoid postponement of milestones.

Time Estimate

Ten to twenty hours per week six months long, scheduled at the author's discretion. This variability is to accommodate lack of sync in PCB printing, parts ordering, potential firmware integration, and test revisions, logistics which may take weeks to order and ship.

Time will be spent in a:

  • In house circuit lab
  • Local hacker space
  • Remote maker space


Work is transparently carried out according to typical distributed Opensource practices. The degree of in house production is maximized to shrink the attack surface introduced by contract manufacturing as well as increase the turn around time of generational testing.


External and prior logic is researched for possible integration. This may include reverse engineering of contending designs by Opensource documentation or closed source (to the legal extent) microscopic inspection.


A schematic diagram is designed using KiCad or equivalent Opensource software. A layout is derived from the schematic and integration work.


Two layer FR4 (flame retardant) substrate is printed according to the prior layout. Four layer substrate may be used, but a external contract manufacturer like Aisler or OSH Park is required for that.


An Sn63Pb37 alloy is applied to the substrate with an injection based solder printer.


The board is populated (stuffed) with components in a standard pick and place procedure. Manual placing is avoided due to error and delay concerns.


The board is baked according to a timed temperature curve yielding a ready to test PCB. An experimental two sided approach may allow for extra density.


Bridged solder pads, air wires, and other mistakes are corrected.


Electrical and optical tests are manually done to identify manufacturing problems. This may include stereoscopic magnification or controlled destruction.


MCU and external flash programming applies primitive bootloader and firmware interface images.


The PCB is ready for use, and a new generation of correction and improvement follows. Start from the beginning (integration step) to optimise the existing design and fulfill more requirements.


Production samples are mailed to investors, testers, and promoters identified during Monero meetings.

Project Plan

Date Milestone FFS Payment
October Initialisation work (platform, communication, and procurement) 314XMR
Early November Tool configs, project documentation, Opendime research 168XMR
Late November Set of PCBs employing secure elements from ST and Atmel
Early December Trezor and Ledger hardware (clone) production 120XMR
Mid December Trezor and Ledger firmware (fork) programming
Late December Mock or prototype demonstration at 34C3 [2]
Early January Midterm report on Trezor and Ledger findings 120XMR
Mid January Custom design and recent feature tailoring
Late January Midterm remix in favor of Monero features
Early February New prototype demonstration at FOSDEM [3] 154XMR
Late February Correlation power analysis, glitch attack trials
Early March PCB generations (schematic and layout improvements) 120XMR
Late March Size and complexity (less or more layers) optimizations
End of term⁸ Demonstration video of a release grade⁹ manufactured board


⁸ Six month conclusion
⁹ Post prototype

Funds are asymmetrically distributed, due to terms of machinery procurement and facilities use. Some correction (not receiving work time reimbursement the first month) attempts to balance this asymmetry.

Progress Reports

Progress is reported in bimonthly Monero developer meetings on the IRC developer channel.

Continuation Plan (Pending New RFC and Revote)

Date Milestone
April First viable wallet with hello world firmware
May Invitation documents produced with instructions
June Virtual community event for alpha testers, demo
August Official release at Black Hat and DefCon


The Monero Project owns this (Opensource) proposal, the blueprint-like result of a month's careful deliberation and research. The author contributed it by uploading content to the forum. Readers are free to print and hand it to investors, colleagues, university professors, or whoever else, in order to start a hardware project of their own.


Source files (text and binary) of all work state Copyright (c) 2017-2018, The Monero Project.


CERN Open Hardware License 1.2

Being a hardware project, no software license is used. Instead, a open hardware license is applied whose terms resemble the other Monero projects' (BSD|MIT) licenses. Patents are more relevant to hardware projects so to counter risk of conflict the CERN OHL is used.

Note: While deliberating between TAPR and CERN, online chats led to a preference for CERN due to its:

  • Poison pill
  • Conciseness
  • Bodaciousness
  • Lack of lame conditions
  • Lack of Eric Raymond complaints
  • Adoption by other like minded projects

Legal Summary

The legal terms mentioned in this text are chosen with the intent of maintaining free and open access to the work. Some call this intellectual property (IP) and others consider deliverables (see section 'Deliverables'.)

These intentions are no different than other Monero projects, and the community is unified in encouraging freedom. Like any other similarly licensed Opensource project, groups and individuals may enjoy the free and open terms as specified in the license.


The project intends to serve as a launchpad for small (one man-hour) to large (one man-year) efforts at distributing Monero featured wallet hardware. Several requirements (see section 'Non/Functional Requirements') support the derivation, customization, marketing, and teaching of how to begin commercialization. All are welcome to participate in this way, and the hope is that we end up with both collaborating and competing groups.


This project proposal was first discussed by Michael, endogenic, and anonimal at the Monero themed party during DefCon 2017.


Teamwork and collaboration from any competent person is encouraged. Outreach to other hardware makers mutually benefits the respective communities.


The hackerspace mailing lists and IRC channels for C-Base, MuCCC, and the Noisebridge will serve to promote, while dedicated lists and channels will serve to support. Outreach is conducted with the EFF, NLNet, and other like minded groups.

Midterm deliverables will be taken to CCC congress at Leipzig in December, possibly Shmoocon in January, and prototype or release grade devices will be distributed at DefCon 2018 (see project plan.) It may be Michael that makes these visits or another person familiar with the project.

Replies: 78
michael edited 6 years ago Weight: 0 | Link [ - ]

Opinion: If the project starts, then there should be coordination with other development like RingCT, RuffCT, Kovri, and whatever else is unique to Monero.

Comment: That's right, and would attend IRC meetings and publish progress reports, trying to sync releases with other relevant development.

Note to myself: Don't forget to review other projects' roadmaps and adjust the RFC-HWALLET-X timeline and project plan accordingly (still at 0.6 and prone to change for just these reasons.)

This is maybe another benefit to controlling the tech behind a dedicated wallet (RFC-HWALLET-1) rather than RFC-HWALLET-2, since we can increase flash size in order to support unique Monero features.

Who (dis)agrees?

michael posted 6 years ago Replies: 1 | Weight: 0 | Link [ - ]

Forum proposal (currently in Open Ideas) 90126 Advancing the Monero Hardware Wallet is now public and welcoming questions and comments. It extends the gains made in this proposal past schematic and layout, integrating bootloader, firmware, mechanical engineering elements, and peripherals as well:

Reply to: michael
ninja_cad posted 6 years ago Replies: 1 | Weight: 0 | Link [ - ]

Do you need a design for the enclosure?

Reply to: ninja_cad michael
michael posted 6 years ago Weight: 0 | Link [ - ]

Hello Ninja,

Yes, we are working towards having an enclosure. This includes design work, and at least a few people are involved. You're quite welcome to participate in this respect, and probably the best way to collaborate is starting with a short status report of mechanical engineering underway. Catch me on IRC (msvb-lab) or email (michael@getmonero) to get this information interactively (with questions and answers.)

Cheers, Michael

michael posted 6 years ago Weight: 0 | Link [ - ]

>I think this is a fine proposal and michael's community presence is an invaluable one.
Hey thanks! I'm quite enthusiastic about closing the gap in my Monero knowledge and contributing accordingly.

michael posted 6 years ago Weight: 0 | Link [ - ]

Question: Why did the budget decrease (a lot) while the time estimate increased?
Answer 1: To accommodate community feedback, where several asked for discount.
Answer 2: To adjust for recent XMR exchange rate variance, which allows less payment for equivalent value.
Answer 3: Community members found the time estimate floor function concluding in 10 hours per questionable, so it is removed in version 0.8.

Thanks a lot for the feedback everyone!

michael posted 6 years ago Weight: 0 | Link [ - ]

Question: The Atmel secure elements fail to support our curve, can the Gemalto Cinterion models do better?
Answer: I found the local Gemalto office last week and want to make a trip there. The datasheets don't specify any ECC cryptography other than key size (of which curve please?)

michael posted 6 years ago Weight: 0 | Link [ - ]

Question: Can the device play the role of a (SSH token | SecurID | password vault) etcetera?
Answer 1: Yes, the components are chosen with attention to support from WolfSSL and MbedSSL, our best chance at a wide variety of firmware interfacing.
Answer 2: Obviously, this is only possible if a developer implements the non cryptocurrency firmware logic in question.

michael edited 6 years ago Weight: 0 | Link [ - ]

Question: Why is a moisture ingress nanocoating (nonpotting waterproof) layer required?
Answer: It's a soft requirement that not only defends against moisture but generally increases resilience and life for a small manufacturing surcharge.

michael posted 6 years ago Weight: 0 | Link [ - ]

Question: Why is a expensive stereo microscope needed?
Answer 1: Several hardware wallet designs are closed source, requiring reverse engineering at high dimensional magnification.
Answer 2: To get some value without paying 100Ks for decapsulation, SEM, FIB, and other services.

michael posted 6 years ago Weight: 0 | Link [ - ]

Question: Why is Opendime (with no wallet functions) receiving attention?
Answer 1: For its use of a weak ATxmega32A4U for strong cryptomethods.
Answer 2: To borrow parts of its miniaturization and cost reduction design.

YAFFY posted 6 years ago Weight: 0 | Link [ - ]

Hi folks! - next generation hardware wallet. Project founded by YAF.FY - Yet Another Foundation for you.

Project already have hardware prototype, and I will show it in couple of weeks. For now crowdfunding started, there is also bounty for new members.

drfloydch posted 6 years ago Replies: 1 | Weight: 0 | Link [ - ]

I don't know if it's allowed, but can be cool to put a link about your initiative on the official download page (hardware wallets section) ?

Reply to: drfloydch
michael posted 6 years ago Replies: 1 | Weight: 0 | Link [ - ]

You mean like an announcement that hardware development is on the way, similar to how the download page leads mobile users to ask for advice in another channel?

Your idea seems quite helpful. I'll create a bug report on the website repository once I'm back on a full keyboard.

Reply to: michael drfloydch
drfloydch posted 6 years ago Weight: 0 | Link [ - ]

Yes, exactly like for the mobile section : "not available now but an interesting community project is on the way" ;).

afighttilldeath posted 6 years ago Replies: 1 | Weight: 0 | Link [ - ]


Reply to: afighttilldeath
michael posted 6 years ago Weight: 0 | Link [ - ]

Thanks a lot for voting for the project with your wallet! Very generous of you.

michael edited 6 years ago Weight: 0 | Link [ - ]

Question: Why is a expensive pick and place machine needed?
Answer 1: Wrong question. It's better to ask, 'how can the chosen machine cost a fraction of 100K?' *. Because the industrial ones are made to the same specs but operate faster. The chosen desktop one is just as accurate but much slower and shorter lived.
Answer 2: It is needed to (1) miniaturize circuits, (2) avoid hand placement errors, (3) allow dozens of samples for a 500 strong community, (4) avoid unhealthy work conditions, (5) reduce delay in test phases, and (6) likely cheaper than six months of express assembly from a local contract manufacturer. All these advantages reduce the risk of project failure considerably.

* Samsung, Fuji, Yamaha, Philips, Juki, Suzuki, and Manncorp all make similar PnP machines, with prices around 100K.

michael edited 6 years ago Weight: 0 | Link [ - ]

Question: Why is there confusion about what competing designs support and who well a Monero port would work?
Answer: The confusion results from (1) poor or lack of documentation and (2) secretive closed source, possibly due to NDA contract terms.

Note: The competing designs are doing an excellent job, but with a different set of expectations and ethic.