| 1 | Requirements in the OpenCoin standards |
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| 2 | |
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| 3 | 1) The system shall be resistant to compromising, i.e. |
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| 4 | * Tokens cannot be falsified without having the minting keys |
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| 5 | * 'Anonymity': issuer should not be able to correlate a minted |
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| 6 | blind to a redeemed token. |
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| 7 | * Everybody should be able to verify if a token is valid (signed |
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| 8 | by the issuer's mint, fulfills the token format specs of the |
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| 9 | issuer, not expired, not spent yet, ...) |
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| 10 | * no double spending possible. There shall be not racecondition |
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| 11 | or other trick to circumvent the double spending check. |
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| 12 | |
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| 13 | 2) Strength against denial of service |
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| 14 | * How to distribute the DSDB (double spending database) |
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| 15 | * How to prevent a malicious receiver from locking a token forever |
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| 16 | making it unredeemable for its owner? |
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| 17 | * How to minimize impact of temporarily unavailable issuer services |
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| 18 | (coin expiration!) |
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| 19 | |
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| 20 | 3) Future directions |
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| 21 | |
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| 22 | * Are there protocols/algorithms besides Chaum which are more suited? |
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| 23 | |
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| 24 | * Receipts: How could mutual reciepts ("i hereby certify that i sent/re- |
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| 25 | ceived 10 opencents from Alice/to Bob") come into play? Can the protocol |
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| 26 | be designed in a way such receipts are mandatory? I.e. the issuer can |
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| 27 | detect if receipts where exchanged and refuses redemption otherwise. |
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| 28 | |
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| 29 | * Offline tokens: There are way to debunk double spenders. How do they |
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| 30 | work? Is it feasable to implement them? |
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| 31 | |
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| 32 | * Transferable tokens (what's the correct term?): with Chaum's protocol, |
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| 33 | every receiver should redeem (or exchange) tokens immediatly. How to make |
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| 34 | tokens 'multi-hop' capable? |
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| 35 | |
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| 36 | * Condionional anonymity: The issuer can detect if blinded tokens are |
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| 37 | blinded such that a trusted third party (e.g. law enforcement agencies) |
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| 38 | could unblind them and refuses minting otherwise. |
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