I stored most of my Bitcoin in a wallet with four backups. Two were paper backups containing only 7 of 12 seed words, and another backup existed on my computer and USB drive. After a power surge, my computer’s HDD failed. When I tried the USB drive, the data was corrupted.

The good news is that the missing words are the last 5 (out of 12). The amount is relatively high (I’ve been in the market since 2013). Recovering the last 5 words is basically the upper practical limit for brute-force recovery today.

Because of this, I started building recovery prototypes in OpenCL, and now in Verilog on FPGAs, to compute hashes and test partial-seed recovery approaches. In my tests, FPGAs showed extremely low energy usage (under 10% of what GPUs consume), although hardware cost is still comparable to high-end GPUs.

I also tried renting machines on VastAI, but the total cost ended up close to simply buying RTX 5090 GPUs.

If anyone is interested, here are the prototypes.

Everything below is open source — no subscription, no paid service, just code and experiments. If it’s useful, feel free to clone/fork. I’m genuinely happy to see people using the code and contributing.

GitHub repositories

ipsbruno3/fpga_bitcoin_seed_rescue
Pipeline / PBKDF2-HMAC-SHA512-oriented workspace for accelerated hardware (FPGA-focused).

ipsbruno/bitcoin_cracking_final
Performance-oriented OpenCL implementation for PBKDF2 workloads on NVIDIA GPUs.

ipsbruno3/bitcoin_electrum_cracking
OpenCL tools for Electrum-related checks; includes checksum-based shortcuts for faster screening (benchmarks included).

ipsbruno3/secp256k1-gpu-accelerator
GPU code for secp256k1 public key generation (point_add / point_mul), with incremental techniques and throughput benchmarks.

ipsbrunoreserva/seedmistake
Typing aid for seed words using Levenshtein distance (matches the nearest BIP39 word).

If you have any questions about the implementations, benchmarks, or the FPGA approach, I’ll be happy to answer.