Algorithm for Digital Cash Transactions

[coolaj86]

We need two terms to use

• Clean (Cash-like, Respectful)
  • Clean transactions are cash-like
  • Normal txes are clean
  • Clean txes are respectful
• Dirty (Greedy, Rude, Irregular, high-entropy)
  • Dirty transactions are irregular, high-entropy
  • Dirty transactions leave fingerprints
  • Dirty transactions are rude to the person you're exchanging with
  • Greedy transactions are dirty

When we deal with cash (or even credit cards), we don't give exact change down to 0.00000001.

For a Cash-like digital currency (such as DASH), we should also follow a principle of rounding.

• pay at least the minimum transaction fee
• pay at least what was requested + 200-400 for tx fee
• probably rounding to the 0.001 DASH when DASH is worth between $5 and $75 (0.5¢-7.5¢)
• there needs to be a way to indicate
  • buyer pays fees vs seller pays fees
  • irregular (high-entropy) transactions
  • preferred cash back denoms
• 💡 there should be no difference between a payment, breaking change, and a coinjoin
  • if that's the case, we generally don't need extra payments back to self
  • (but if we do, there should always be multiple)
• must be easy to port, must have reference tests

For certain applications (such as Dash Direct), this may need to be turned off.

Ideal:

• no per transaction fee
• scattershot reputation-based broker feen

Runner Up:

• Cash
  • 1000.0 (special)
  • 200.0, 100.0, 50.0
  • 20.0, 10.0, 5.0
  • 2.0, 1.0, 0.5
  • 0.2, 0.1, 0.05
  • 0.02, 0.01, 0.005
  • 0.002, 0.001
• Stamps - 0.00001000, 0.00000500, 0.00000200