{"action":"created","issue":{"url":"https://api.github.com/repos/zcash/zcash/issues/853","repository_url":"https://api.github.com/repos/zcash/zcash","labels_url":"https://api.github.com/repos/zcash/zcash/issues/853/labels{/name}","comments_url":"https://api.github.com/repos/zcash/zcash/issues/853/comments","events_url":"https://api.github.com/repos/zcash/zcash/issues/853/events","html_url":"https://github.com/zcash/zcash/issues/853","id":147186800,"number":853,"title":"Zerocash paper does not specify that v^new_i and v_pub are in [0, v_max].","user":{"login":"daira","id":643204,"avatar_url":"https://avatars.githubusercontent.com/u/643204?v=3","gravatar_id":"","url":"https://api.github.com/users/daira","html_url":"https://github.com/daira","followers_url":"https://api.github.com/users/daira/followers","following_url":"https://api.github.com/users/daira/following{/other_user}","gists_url":"https://api.github.com/users/daira/gists{/gist_id}","starred_url":"https://api.github.com/users/daira/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/daira/subscriptions","organizations_url":"https://api.github.com/users/daira/orgs","repos_url":"https://api.github.com/users/daira/repos","events_url":"https://api.github.com/users/daira/events{/privacy}","received_events_url":"https://api.github.com/users/daira/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/zcash/zcash/labels/documentation","name":"documentation","color":"906b75"},{"url":"https://api.github.com/repos/zcash/zcash/labels/engineering%20meeting%20agenda","name":"engineering meeting agenda","color":"8fe4ff"},{"url":"https://api.github.com/repos/zcash/zcash/labels/SECURITY","name":"SECURITY","color":"e01010"},{"url":"https://api.github.com/repos/zcash/zcash/labels/Zerocash%20paper","name":"Zerocash paper","color":"f97695"}],"state":"open","locked":false,"assignee":{"login":"imichaelmiers","id":1102962,"avatar_url":"https://avatars.githubusercontent.com/u/1102962?v=3","gravatar_id":"","url":"https://api.github.com/users/imichaelmiers","html_url":"https://github.com/imichaelmiers","followers_url":"https://api.github.com/users/imichaelmiers/followers","following_url":"https://api.github.com/users/imichaelmiers/following{/other_user}","gists_url":"https://api.github.com/users/imichaelmiers/gists{/gist_id}","starred_url":"https://api.github.com/users/imichaelmiers/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/imichaelmiers/subscriptions","organizations_url":"https://api.github.com/users/imichaelmiers/orgs","repos_url":"https://api.github.com/users/imichaelmiers/repos","events_url":"https://api.github.com/users/imichaelmiers/events{/privacy}","received_events_url":"https://api.github.com/users/imichaelmiers/received_events","type":"User","site_admin":false},"milestone":null,"comments":1,"created_at":"2016-04-10T02:52:51Z","updated_at":"2016-04-11T18:57:09Z","closed_at":null,"body":"It specifies this in section 4.2 point 2. for v<sup>old</sup><sub>1..2</sub>, but not for v<sup>new</sup><sub>1..2</sub> and v<sub>pub</sub>, which is inconsistent. (It would be sufficient to specify that all of these values are nonnegative, since their sum is equal to v<sup>old</sup><sub>1</sub> + v<sup>old</sup><sub>2</sub> which is ≤ v<sub>max</sub>.)\r\n\r\nIn fact, values outside the range of unsigned 64-bit integers are not representable in the input to the coin commitments, so conditions 1. (d) and 1. (e) are not well-defined unless 0 ≤ v<sup>old</sup><sub>1..2</sub>, v<sup>new</sup><sub>1..2</sub> < 2<sup>64</sup> - 1. However, it would be confusing to rely on that *implicit* constraint. There appears to be no (implicit or explicit) range constraint specified for v<sub>pub</sub>.\r\n\r\nSee https://github.com/zcash/zips/issues/41 for a related issue in the Zcash protocol spec. There is an intentional difference between Zerocash and Zcash (ZCP 2.0) in that the maximum Zcash note value is ``MAX_MONEY`` = 21000000 \\* 10<sup>8</sup>, not 2<sup>64</sup> - 1.\r\n\r\nSee #854 for a related issue in the Zcash implementation."},"comment":{"url":"https://api.github.com/repos/zcash/zcash/issues/comments/208498661","html_url":"https://github.com/zcash/zcash/issues/853#issuecomment-208498661","issue_url":"https://api.github.com/repos/zcash/zcash/issues/853","id":208498661,"user":{"login":"daira","id":643204,"avatar_url":"https://avatars.githubusercontent.com/u/643204?v=3","gravatar_id":"","url":"https://api.github.com/users/daira","html_url":"https://github.com/daira","followers_url":"https://api.github.com/users/daira/followers","following_url":"https://api.github.com/users/daira/following{/other_user}","gists_url":"https://api.github.com/users/daira/gists{/gist_id}","starred_url":"https://api.github.com/users/daira/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/daira/subscriptions","organizations_url":"https://api.github.com/users/daira/orgs","repos_url":"https://api.github.com/users/daira/repos","events_url":"https://api.github.com/users/daira/events{/privacy}","received_events_url":"https://api.github.com/users/daira/received_events","type":"User","site_admin":false},"created_at":"2016-04-11T18:57:09Z","updated_at":"2016-04-11T18:57:09Z","body":"See https://github.com/zcash/zcash/issues/854#issuecomment-208497102"}}