| 摘要 |
A digital wallet stores a cryptographically camouflaged access-controlled datum (330), e.g., a private key encrypted under the user's PIN (300). Entry of the correct PIN will correctly decrypt the stored key (330). Entry of certain "pseudo-valid" PINs will also decrypt the stored key, but incorrectly, resulting in a candidate key indistinguishable from the correct key (350). Such pseudo-valid PINs are spread thinly over the space of PINs, so that the valid user is unlikely to realize a pseudo-valid PIN via a typographical error in entering the correct PIN. In existing wallet technologies only the correct PIN produces a candidate key; thus, hackers can discover the correct PIN by exhaustive search. |
