The Puzzle

The Puzzle
Cropped logo
Project
Status	Active
Category	Cryptography, Mathematics
Compute	CPU & GPU
Requires	None
Development
Developer	Rytis Slatkevičius
Author	Rytis Slatkevičius
Sponsor	IĮ Technologica Ecliptica
Maintainer	Rytis Slatkevičius
Initial release	October 30, 2026  (0 years ago)
Completed	No
Software
Written in	C, C++
Operating system	Windows, Linux
Size	~10 MB
BOINC statistics
Stats as of	November 2, 2026  (0 years ago)
Performance	13.431 TFLOPS
Active users	54
Total users	336
Active hosts	191
Total hosts	191
Analytics
GPU performance	13.282 TFLOPS
CPU performance	149 GFLOPS
Metadata
Website	https://thepuzzle.cloud/
License	Proprietary (wrapper: LGPL-3.0-or-later)

The Puzzle is an active BOINC-based volunteer computing project that harnesses donated computer processing power to search for the private key of an unclaimed Bitcoin challenge address. It is catalogued among the active distributed computing initiatives documented in this wiki's BOINC projects directory. The project is developed and operated by veteran volunteer computing engineer Rytis Slatkevičius, founder of PrimeGrid and creator of The Science Cloud, through his enterprise IĮ Technologica Ecliptica based in Lithuania.

The Puzzle focuses exclusively on solving target #71 of the 2015 Bitcoin puzzle transaction, which contains approximately 7.1 BTC. Unlike traditional cryptocurrency mining, the project does not mint new tokens, validate transactions, or secure the blockchain network. Instead, it carries out a structured brute-force search over a mathematically bounded 70-bit interval on the secp256k1 elliptic curve. If the private key is recovered, the project provides a legally binding prize-sharing agreement under Lithuanian law, dividing proceeds between taxes, infrastructure operations, and participating volunteers in direct proportion to their validated BOINC credit.

The project's launch in late October 2026 followed intense community debate surrounding BitBOINC, an earlier multi-application project that had initiated a similar cryptographic puzzle hunt without open-source transparency or an enforceable reward structure.

History and background

The Bitcoin logo. The Bitcoin puzzle challenge was established in 2015 as a public demonstration of cryptographic difficulty across increasing keyspace sizes.

On 15 January 2015, an anonymous entity transferred funds to 256 distinct Bitcoin addresses within a single transaction recorded in block 339085. The transaction created a public benchmark for discrete-logarithm search bounds by assigning private keys of sequentially increasing bit lengths. Specifically, for puzzle number $n$, the private key was chosen uniformly from the interval:

$2^{n-1}\le k<2^n$

Under this construction, puzzle #1 required checking a 1-bit space, puzzle #2 a 2-bit space, and puzzle #160 a 160-bit space. Early, narrow-range puzzles were solved quickly by individuals and small computing clusters. Over the subsequent decade, collaborative search groups and mining pools solved puzzles sequentially up to #70.

Puzzle #71, linked to public address 1PWo3JeB9jrGwfHDNpdGK54CRas7fsVzXU, is the lowest remaining unsolved challenge in the sequence. The address holds a balance of approximately 7.100 BTC. Because each additional bit doubles the keyspace, puzzle #71 encompasses a range of $2^{70}$ possible keys (approximately 1.18 sextillion values), presenting a search space too vast for individual workstations but within reach of organized volunteer computing grids.

The Puzzle project was formally opened to the public on 30 October 2026 at 09:03:35 UTC by Rytis Slatkevičius. Participants could join directly via the project website or connect through their account on The Science Cloud, a BOINC infrastructure and account management platform. On 31 October 2026, the project published formal clarifications regarding prize distribution, tax handling, and claim deadlines. On 2 November 2026, version 1.10 of the primary search application was deployed across Windows and Linux platforms, introducing production support for NVIDIA GPU processing alongside multi-threaded CPU routines.

Controversy involving BitBOINC and project origins

The creation of The Puzzle occurred against the backdrop of significant controversy within the volunteer computing community regarding another project, BitBOINC. BitBOINC had launched on 28 September 2026 under the administration of developer Alperen Yavuz (operating as part of the Athena network), aiming to deploy volunteer computing power to search for Bitcoin puzzle keys alongside several astrophysics applications.

The BitBOINC dispute

BitBOINC deployed two applications for its Bitcoin puzzle search: Potamos, a sequential brute-force scan targeting puzzle #71, and Keraunos, a Pollard kangaroo algorithm search targeting puzzle #140. The project quickly encountered sharp opposition from established volunteer computing groups and third-party statistics providers:

1. Third-party delisting and trust issues: On its launch day, 28 September 2026, BitBOINC was delisted by major independent statistics tracker Free-DC. Free-DC administrator Skillz publicly stated that the project would not be tracked due to concerns over accountability, noting that an anonymous operator was soliciting free computing power from volunteers to hunt for cryptocurrency worth millions of dollars on a personal "pinky promise" of future scientific donations.
2. Governance and reward structure: Unlike academic BOINC projects where compute time contributes to public science, the cryptocurrency hunt offered direct monetary returns. However, BitBOINC's published terms proposed that volunteer rewards would be distributed through an informal "weighted random drawing" among recent contributors to a solved puzzle, rather than an equitable, legally binding revenue share.
3. Community tensions and forum bans: Heightened friction on Discord and the official BOINC community message boards culminated in BitBOINC's operator being permanently banned by volunteer BOINC forum moderator Jord, who cited policy violations and confrontational conduct.
4. Code opacity and GitHub release timeline: While BitBOINC published the source code for its gravitational microlensing application (Kampylos), its cryptographic applications remained closed-source. On GitHub, the operator's account (alplix) did not register repositories for its puzzle applications until nearly a month after project launch:
   • alplix/keraunos was created on 26 October 2026 at 11:47:10 UTC.
   • alplix/potamos was created on 26 October 2026 at 11:47:18 UTC.
   • alplix/sphinx (for the Certicom challenge) was created on 26 October 2026 at 11:47:25 UTC.
   • alplix/thermopsis was created on 26 October 2026 at 20:15:47 UTC.
   • alplix/bitboinc-android was created on 27 October 2026 at 15:46:21 UTC.

   Crucially, these GitHub repositories were designated as "Documentation only" stubs containing descriptive README files rather than compilable application source code, work-unit generators, or searched range records.

The Puzzle as an institutional alternative

Recognizing volunteer interest in mathematical key-search challenges but acknowledging the governance vacuum that had triggered the BitBOINC controversy, Rytis Slatkevičius launched The Puzzle on 30 October 2026. The new project differed from BitBOINC in several structural ways:

• Established operator reputation: Slatkevičius has been an active figure in the volunteer computing ecosystem since 2005, when he created PrimeGrid (originally Message@Home) to test PerlBOINC. As an established contributor to BOINC for over two decades, his leadership offered institutional credibility.
• Legally binding revenue sharing: Rather than relying on discretionary sweepstakes, The Puzzle instituted explicit contractual prize-sharing rules governed by the laws of the Republic of Lithuania, ensuring that 40% (or 50% if paid in Bitcoin) of any recovered value is distributed to volunteers strictly in proportion to their accumulated credit.
• Open progress reporting: Unlike BitBOINC's policy of withholding searched subranges, The Puzzle publishes exact cumulative progress metrics directly on its homepage, detailing the percentage of keyspace covered by project volunteers, daily throughput, and externally completed blocks.
• Single-target focus: While BitBOINC divided resources across multiple puzzle targets and scientific subprojects, The Puzzle concentrated all computational throughput onto puzzle #71.

Mathematical foundation and cryptographic search

Graph of the elliptic curve secp256k1 over real numbers ($y^2=x^3+7$), the mathematical curve utilized in Bitcoin public-key derivation.

The security of Bitcoin addresses relies on elliptic-curve cryptography and one-way cryptographic hash functions. A private key $k$ is an integer scalar selected within the group order of the secp256k1 curve.

Key derivation on secp256k1

The secp256k1 elliptic curve is defined over the prime finite field ${\mathbb{𝔽}}_p$ by the short Weierstrass equation:

$y^2\equiv x^3+7(\mathrm{mod}p)$

where the field prime is:

$p=2^{256}-2^{32}-977$

A candidate private key $k$ determines a corresponding public key point $P$ through scalar multiplication with the standardized base generator point $G$:

$P=k\cdot G=G+G+\dots +G(k\text{ times})$

Elliptic-curve point addition is efficient to compute in the forward direction. However, finding $k$ given only $P$ constitutes the elliptic-curve discrete logarithm problem (ECDLP), which admits no known polynomial-time solution on classical computers.

Address generation and one-way hashing

In Bitcoin's standard Pay-to-Pubkey-Hash (P2PKH) scheme, the public key $P$ is not directly exposed as the address. Instead, the serialized coordinates of $P$ undergo successive cryptographic hashing:

$H=\text{RIPEMD-160}(\text{SHA-256}(P))$

The resulting 160-bit hash $H$ is prepended with a network version byte (0x00 for mainnet) and appended with a 4-byte checksum computed via double SHA-256, before being serialized in Base58Check encoding to produce the public address string:

$\text{Address}=\text{Base58Check}(0\text{x}00\parallel H)$

Because the composition $\text{RIPEMD-160}\circ \text{SHA-256}$ is a pre-image resistant hash function, the public key point $P$ cannot be reconstructed from the public address string.

Search complexity for Puzzle #71

For puzzle #71, the target address 1PWo3JeB9jrGwfHDNpdGK54CRas7fsVzXU has never spent funds or published a signed transaction to the blockchain. Consequently, its public key $P$ remains completely hidden, leaving only the 160-bit hash $H$ known.

Because $P$ is unknown, advanced discrete-logarithm algorithms such as Pollard's kangaroo algorithm or baby-step giant-step, which require group operations on known curve points, cannot be applied. The search is therefore mathematically constrained to sequential or segmented exhaustive enumeration. Every candidate scalar $k$ must be multiplied by $G$, hashed through SHA-256 and RIPEMD-160, and evaluated against the target hash.

The defined scalar interval for puzzle #71 is:

$2^{70}\le k<2^{71}$

In hexadecimal notation, this corresponds to:

${\text{0x400000000000000000}}_{16}\le k\le {\text{0x7fffffffffffffffff}}_{16}$

The total search space spans:

$|K|=2^{71}-2^{70}=2^{70}\approx 1.18059\times 10^{21}\text{ candidate keys}$

Because the private key was chosen randomly within this range, every key holds an identical probability of discovery. The search concludes as soon as a collision is verified, without requiring completion of the entire keyspace.

Computational architecture and applications

Task partitioning and work unit generation

The Puzzle server segments the $2^{70}$ keyspace into discrete, non-overlapping search blocks. Each block spans an interval of:

$2^{34}=17,179,869,184\text{ keys}\approx 1.718\times 10^{10}\text{ keys}$

The entire keyspace comprises:

$\frac{2^{70}}{2^{34}}=2^{36}=68,719,476,736\text{ potential work units}$

Each task dispatched to a volunteer machine assigns one or more blocks, calibrated to run for approximately one hour of wall-clock time on modern hardware. Upon task completion, the client returns an encrypted result file to the server. The server verifies the computation before awarding BOINC credit.

Software implementation and licensing

The search application, named keyrange, is a proprietary, high-performance binary developed by IĮ Technologica Ecliptica. While the search core itself is closed-source to safeguard against range-skipping and front-running exploits, it incorporates several standard open-source libraries:

• libsecp256k1: Optimized C library for elliptic-curve scalar multiplication and point arithmetic, developed by Pieter Wuille and released under the MIT licence.
• BOINC wrapper: Manages execution, monitoring, and checkpointing inside the BOINC client environment. Distributed under the GNU LGPL version 3 or later. The project publishes its custom patch enlarging the command-line buffer on Linux.
• libzip and zlib: Embedded compression libraries utilized by the BOINC wrapper (BSD 3-clause and zlib licences).
• mingw-w64 runtime: Supplies Windows threading and runtime dependencies via winpthreads (ZPL 2.1, MIT, and BSD 3-clause licences).

Platform support

As of 2 November 2026, The Puzzle distributes application version 1.10 across the following computing environments:

Platform	Application variant	Architecture	Primary hardware
Microsoft Windows	1.10 (mt)	x86_64 / EM64T	Multi-threaded CPU
Microsoft Windows	1.10 (cuda)	x86_64 / EM64T	NVIDIA GPU (Modern CUDA)
Microsoft Windows	1.10 (cuda11)	x86_64 / EM64T	NVIDIA GPU (Legacy CUDA 11)
Linux	1.10 (mt)	x86_64 / EM64T	Multi-threaded CPU
Linux	1.10 (cuda)	x86_64 / EM64T	NVIDIA GPU (Modern CUDA)
Linux	1.10 (cuda11)	x86_64 / EM64T	NVIDIA GPU (Legacy CUDA 11)

The multi-threaded CPU application automatically occupies all processor cores permitted by the volunteer's BOINC preferences. The application maintains a minimal resource profile, requiring only several megabytes of RAM and negligible disk storage.

Prize distribution and legal governance

The Puzzle operates under a binding prize-sharing charter established to ensure transparency and prevent internal misappropriation. If the private key is identified, the on-chain assets (nominally 7.100 BTC) are allocated according to a fixed formula:

Allocation	Share (Fiat disbursement)	Share (Direct Bitcoin payout)	Purpose
Taxes	20%	0% (Volunteer portion untaxed at source)	Legal tax compliance under Lithuanian tax law
Project operator	40%	50%	Server hosting, bandwidth, infrastructure, and administration
Volunteers	40%	50%	Proportional distribution among participating contributors

Credit-proportional distribution

The volunteer prize share is distributed strictly on a merit basis according to valid work submitted prior to the solve. For any volunteer $i$ with accumulated project credit $C_i$ out of total valid project credit $C_{\text{total}}$, the reward $S_i$ is given by:

$S_i=S_{\text{volunteers}}\times \left(\frac{C_i}{C_{\text{total}}}\right)$

Crucially, the prize distribution rules stipulate that it does not matter which individual computer discovers the key. The host that returns the winning block receives the same credit-proportional share as any other participant, eliminating the "lottery" dynamic and encouraging consistent hardware contribution.

Payout rules and thresholds

The project establishes clear operational rules governing prize disbursement:

1. Eligibility cutoff: Only tasks validated by the server before receipt of the winning key qualify for credit calculation. Tasks submitted after discovery are excluded from that puzzle's prize pool.
2. Single-puzzle accounting: Contribution counters used for prize sharing reset to zero upon the conclusion of puzzle #71, whether solved by The Puzzle or an external group. Standard BOINC credits on user profiles remain unchanged.
3. Disbursement tiers: Volunteer shares are evaluated in euros on the date amounts are finalized:
   • Above 50 €: Disbursed in Bitcoin, euros, or US dollars at the volunteer's discretion.
   • 1 € to 50 €: Disbursed in euros, US dollars, or credited directly to the participant's account on The Science Cloud.
   • Below 1 €: Forfeited due to banking and transaction processing overhead, and donated in full to Sengirės fondas, a Lithuanian conservation foundation dedicated to protecting old-growth ancient forests.
4. Claim window: Beneficiaries must claim their prize within 30 calendar days of finalization; unclaimed shares are forfeited.
5. Anti-frontrunning clause: If a participant discovers the private key using project work units and attempts to claim the funds independently on-chain, project terms mandate that the funds belong to the collective project and must be returned for distribution under project rules.
6. Legal jurisdiction: All prize sharing, contractual agreements, and distributions are legally governed by the laws of the Republic of Lithuania.

Volunteer computing and statistics

As of 2 November 2026, The Puzzle demonstrates rapid early adoption across the volunteer computing community.

Metric	Value (as of 2 November 2026)	Source
Overall computing throughput	13,431 GFLOPS (13.431 TFLOPS average)	Applications registry
Peak active throughput	52,298.77 GFLOPS (52.299 TFLOPS)	Server status daemon
GPU computing throughput	13,282 GFLOPS (13.282 TFLOPS)	Applications registry
CPU computing throughput	149 GFLOPS (0.149 TFLOPS)	Applications registry
Active users with credit	54	Server status daemon
Total registered users	336+	Server status daemon
Active hosts with credit	191	Server status daemon
Tasks in progress	6,837	Server status daemon
Tasks ready to send	4,977	Server status daemon
Cumulative keyspace checked	0.0023% (approx. 2.71 quadrillion keys)	Project homepage
24-hour search rate	0.00073% of keyspace	Project homepage

See also

• BOINC projects
• BitBOINC
• PrimeGrid
• BOINC Central
• iThena.Computational
• iThena.Measurements
• WUProp@Home
• Yoyo@home
• Gaia@home
• Einstein@Home
• MilkyWay@home
• Universe@Home
• SETI@home

External links

• The Puzzle official website
• About The Puzzle and prize distribution terms
• The Puzzle server status
• The Puzzle applications and computing statistics
• The Science Cloud
• Bitcoin puzzle #71 address on Mempool Space
• Sengirės fondas (Ancient Woods Foundation)