GPU rental guide — lotterypzl

You don't need to own GPUs to hunt Bitcoin puzzles. Both Vast.ai and Clore.ai let you rent NVIDIA GPUs by the hour. This guide walks you through the entire process — verified against official docs as of June 2025.

Disclosure: The Vast.ai and Clore.ai links in this guide are referral links. If you sign up through them, we may earn a small commission at no extra cost to you. This helps support the project.

Choose a platform

Vast.ai

Larger marketplace, more GPU variety, lower prices. Best for cost-effective hunting.

Auth: SSH keys only (no passwords)
Min deposit: ~$5
Payment: Credit card, crypto
Docs: docs.vast.ai →

Clore.ai

Crypto-native, European hosting, simpler interface. Best for crypto payments.

Auth: SSH password or keys
Min deposit: Small (CLORE token or crypto)
Payment: CLORE, BTC, USDT
Docs: docs.clore.ai →

Choose a GPU

For puzzle hunting, you need NVIDIA GPUs with high CUDA core counts. Here's how the popular cards compare for brute-force key scanning.

GPU	CUDA cores	VRAM	~Keys/sec (BitCrack)	~Cost/hr (Vast)	Best for
RTX 3070	5,888	8 GB	~1.5 Bkeys/s	~$0.07	Budget scanning (puzzle 71)
RTX 3080	8,704	10 GB	~2.5 Bkeys/s	~$0.12	Good value
RTX 3090	10,496	24 GB	~3.5 Bkeys/s	~$0.20	Kangaroo (needs VRAM)
RTX 4070	5,888	12 GB	~2.8 Bkeys/s	~$0.15	Modern efficiency
RTX 4090	16,384	24 GB	~6.0 Bkeys/s	~$0.35	Best performance

Benchmarks are approximate community estimates for BitCrack address-only scanning. Actual speeds vary by tool, range, and clock speed. Kangaroo (for known-pubkey puzzles) needs significantly more VRAM — RTX 3090/4090 with 24GB are strongly preferred. btcpuzzle.info maintains a community benchmark list →

ASICs don't work. Bitcoin mining ASICs (Antminer, etc.) are SHA-256d only. Puzzle hunting needs elliptic curve operations — only GPUs (and CPUs, slowly) can do this. Don't rent or buy ASICs for puzzle hunting.

Set up SSH keys

You need SSH to connect to your rental. Both platforms support SSH keys — Vast.ai requires them (no password auth).

generate SSH key

# generate an ed25519 key (recommended, modern, fast)
ssh-keygen -t ed25519 -C "puzzle-hunting"

# view your public key — you'll paste this into Vast/Clore
cat ~/.ssh/id_ed25519.pub

Add key to Vast.ai

Go to Vast.ai → Account → Keys
Paste your public key
Keys apply to new instances only — existing instances need manual addition

Source: Vast.ai SSH docs →

Add key to Clore.ai

Go to Account → SSH Keys
Click Add Key
Paste your public key
Key auto-deploys to all new rentals

Source: Clore.ai connection docs →

Rent an instance

On Vast.ai

Go to cloud.vast.ai → Search offers
Filter: GPU type (e.g. RTX 3070), reliability > 0.9, price ascending
Choose a machine. Click Rent
Select launch mode: SSH (not Jupyter)
Use Docker image: nvidia/cuda:12.2.0-runtime-ubuntu22.04
Start the instance. Wait for "Running" status
Click the SSH icon to get your connection string

On Clore.ai

Go to clore.ai → Marketplace
Filter by GPU type and price
Choose a server. Select On-Demand (not Spot — you don't want to lose your session)
Choose Docker image: nvidia/cuda:12.8.0-base-ubuntu22.04
Open ports: 22 (SSH, TCP)
Place the order. Wait 2-3 minutes for boot
Check My Orders → order details for IP and SSH port

Source: Clore.ai Docker images →

Connect via SSH

connect.sh

# Vast.ai — copy the SSH string from the dashboard
ssh -p 20544 root@142.214.185.187

# Clore.ai — use IP and port from order details
ssh root@185.123.45.67 -p 22022

# verify GPU is visible
nvidia-smi

Vast.ai uses tmux by default. When you SSH in, you're placed in a tmux session. This protects your processes from SSH disconnects. To disable it: touch ~/.no_auto_tmux. Vast.ai SSH docs →

Install puzzle hunting tools

Once connected, install the tools you need. Here's the fastest path for BitCrack (brute force) and Kangaroo (pubkey known).

install tools

# update system
apt update && apt install -y build-essential cmake git curl

# --- BitCrack (GPU brute force, address-only) ---
git clone https://github.com/brichard19/BitCrack.git
cd BitCrack/Build
cmake .. -DCUDA_ENABLE=ON
make
cd ../Release

# test it — scan puzzle #71 range against its address
./cuBitCrack --keyspace 400000000000000000:7fffffffffffffffff \
  -c 1 1PWo3JeB9jrGwfHDNpdGK54CRas7fsVzXU

# --- Kangaroo (GPU, for puzzles with known public key) ---
git clone https://github.com/JeanLucPons/Kangaroo.git
cd Kangaroo
make

# create input file for puzzle 135 (known public key)
cat > 135.txt << 'EOF'
4000000000000000000000000000000000
7fffffffffffffffffffffffffffffffff
02145d2611c823a396ef6712ce0f712f09b9b4f3135e3e0aa3230fb9b6d08d1e16
EOF

./Kangaroo -gpu 135.txt

For puzzles 130+, use Etayson's modified kangaroo instead of JeanLucPons. For the SOTA kangaroo implementation, see RCKangaroo by RetiredC.

Keep your session alive

Rental instances charge by the hour. If your SSH disconnects, your process may die (unless you use tmux/screen). For long sessions, use lotterypzl --detach or run inside tmux:

session management

# start a named tmux session
tmux new -s puzzle71

# run your scan inside tmux
./cuBitCrack --keyspace 400000000000000000:7fffffffffffffffff \
  -c 1 1PWo3JeB9jrGwfHDNpdGK54CRas7fsVzXU

# detach: Ctrl+B then D
# reconnect later:
tmux attach -t puzzle71

Security checklist

While scanning

Never store found keys on the rental instance. If you find a key, write it down offline immediately and wipe it from the machine.
Don't share the instance IP. Other users on the same host could potentially access your container.
Use untrusted_computer mode if your tool supports it — prevents key storage on disk.
Check nvidia-smi periodically — if the GPU is shared, you may not get full performance.

After scanning

Wipe the instance: rm -rf /workspace/* before terminating
Terminate the rental — don't leave it running and accumulating charges
Verify charges — check your billing dashboard for unexpected costs
If you found a key: follow our How to Claim guide before doing anything else

GPU rentals are not private. The host machine's owner can theoretically see your container's processes and files. Treat rental instances as untrusted. Never paste private keys, never leave found keys on disk, and always wipe before terminating. If you find a key, disconnect immediately and follow the safe claiming procedure from your own machine.

Official documentation

Vast.ai SSH guide Keys, connection, tmux, port forwarding Vast.ai docs Full documentation Clore.ai connection guide SSH, Jupyter, file transfer, port forwarding Clore.ai Docker images Pre-built images and custom images Clore.ai docs Full documentation Puzzle hunting tools Our complete tool directory