Have you heard of the "Bitcoin Wallet Cracking Contest" that started in 2015? This is not an ordinary event.

Back then, someone conducted a bold experiment to prove the security of Bitcoin private key space: creating 160 wallets with increasing difficulty levels, with a total of 1000 BTC as the prize pool. The rules were straightforward—whoever can crack the wallet's private key gets to take the coins inside.

**How does the difficulty increase?**

Wallet #1 is the simplest, with private keys ranging from 2^0 to 2^1, only one number "1." Sounds manageable. But as you go further, the difficulty explodes exponentially. Wallet #2's private keys can only be "2" or "3," wallet #3's range is 4–7... and so on, stacking up.

By wallet #130, the private key range is from 2^129 to 2^130, with the number of bits soaring to 33. Pushing further to wallet #160? The private key length jumps to 40 bits.

**What does these 40 bits mean?**

Look at it from another perspective. Suppose you want to store all possible private keys for wallet #160 in a TXT text file (each private key is 40 bytes). How much storage space would that require?

2^159 ≈ 7.3×10^47 private keys × 40 bytes ≈ 2.9×10^49 bytes

Converted, that’s: **29,000,000,000,000,000,000,000,000,000,000,000,000,000 TB** (29 followed by 36 zeros).

Imagine that—this is the storage capacity you would need. And this is just for ONE wallet.

In comparison, the total theoretical number of Bitcoin private key addresses is 2^256. From this perspective, cracking wallet #160 is approaching the limit of feasibility.

**How has progress been?**

Since 2015, nearly 10 years have passed. Out of these 160 wallets, only about 50% have been successfully cracked—that is, 80 wallets. The remaining 80 are still sitting there, with the BTC inside quietly sleeping.

If you want to learn more, just search online for "Bitcoin Puzzle Transaction." This challenge, from design to execution, is the ultimate test of cryptographic security.