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0 sats \ 0 replies \ @klk 14 Jun \ on: Brute force and the coins are yours bitcoin
Looking at this BIP38 encrypted wallet challenge, I can make some educated guesses about the passphrase characteristics and brute force feasibility:

Passphrase Analysis

Likely Characteristics:
  • Length: Probably 8-20 characters (user mentioned combining 3 passwords, but likely not the full 30 characters)
  • Character set: Likely alphanumeric only (a-z, A-Z, 0-9) based on user saying "probably not with special characters"
  • Dictionary words: Possibly - user mentioned not using a password manager and needing to remember it, suggesting human-memorable patterns
Estimated Character Set Sizes:
  • Lowercase only: 26 characters
  • Alphanumeric (mixed case): 62 characters
  • Alphanumeric + common symbols: ~95 characters

Brute Force Time Estimates (RTX 3090)

BIP38 uses scrypt with heavy parameters (N=16384, r=8, p=8), making it very slow to compute. An RTX 3090 can achieve roughly 1,000-5,000 BIP38 attempts per second.
Time estimates for different scenarios:
LengthCharacter SetCombinationsTime (Average)
8 charsLowercase (26)2.1×10¹¹1-2 years
10 charsLowercase (26)1.4×10¹⁴900-4,500 years
8 charsAlphanumeric (62)2.2×10¹⁴1,400-7,000 years
12 charsAlphanumeric (62)3.2×10²¹20+ million years

Realistic Attack Strategies

Rather than pure brute force, more practical approaches would be:
  1. Dictionary attacks - Common passwords, personal info
  2. Hybrid attacks - Dictionary words + numbers/years
  3. Pattern-based attacks - Since user mentioned combining 3 passwords
  4. Wordlist attacks - Using leaked password databases

Verdict

Pure brute force is likely infeasible even with a 3090, unless the passphrase is very short (≤8 characters) and uses a limited character set. The BIP38 scrypt parameters were specifically designed to make brute forcing prohibitively expensive.
The 500k sats might not justify the electricity costs for extended brute forcing, especially given the astronomical time estimates for longer passphrases.
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