{"action":"created","issue":{"url":"https://api.github.com/repos/jedisct1/libsodium/issues/681","repository_url":"https://api.github.com/repos/jedisct1/libsodium","labels_url":"https://api.github.com/repos/jedisct1/libsodium/issues/681/labels{/name}","comments_url":"https://api.github.com/repos/jedisct1/libsodium/issues/681/comments","events_url":"https://api.github.com/repos/jedisct1/libsodium/issues/681/events","html_url":"https://github.com/jedisct1/libsodium/issues/681","id":298004072,"number":681,"title":"Why does Key Exchange use unkeyed blake2b?","user":{"login":"riobard","id":22984,"avatar_url":"https://avatars3.githubusercontent.com/u/22984?v=4","gravatar_id":"","url":"https://api.github.com/users/riobard","html_url":"https://github.com/riobard","followers_url":"https://api.github.com/users/riobard/followers","following_url":"https://api.github.com/users/riobard/following{/other_user}","gists_url":"https://api.github.com/users/riobard/gists{/gist_id}","starred_url":"https://api.github.com/users/riobard/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/riobard/subscriptions","organizations_url":"https://api.github.com/users/riobard/orgs","repos_url":"https://api.github.com/users/riobard/repos","events_url":"https://api.github.com/users/riobard/events{/privacy}","received_events_url":"https://api.github.com/users/riobard/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":0,"created_at":"2018-02-17T13:15:40Z","updated_at":"2018-02-17T13:44:56Z","closed_at":null,"author_association":"NONE","body":"https://github.com/jedisct1/libsodium/blob/8b9b6a54be5490449e0c5e535aa257d6406b04b2/src/libsodium/crypto_kx/crypto_kx.c#L58\r\n\r\nThe construction is `x || tx = BLAKE2B-512(p.n || client_pk || server_pk)`. I'm wondering what's the security of prepending the key vs using keyed blake2b instead?"},"comment":{"url":"https://api.github.com/repos/jedisct1/libsodium/issues/comments/366442398","html_url":"https://github.com/jedisct1/libsodium/issues/681#issuecomment-366442398","issue_url":"https://api.github.com/repos/jedisct1/libsodium/issues/681","id":366442398,"user":{"login":"jedisct1","id":124872,"avatar_url":"https://avatars2.githubusercontent.com/u/124872?v=4","gravatar_id":"","url":"https://api.github.com/users/jedisct1","html_url":"https://github.com/jedisct1","followers_url":"https://api.github.com/users/jedisct1/followers","following_url":"https://api.github.com/users/jedisct1/following{/other_user}","gists_url":"https://api.github.com/users/jedisct1/gists{/gist_id}","starred_url":"https://api.github.com/users/jedisct1/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jedisct1/subscriptions","organizations_url":"https://api.github.com/users/jedisct1/orgs","repos_url":"https://api.github.com/users/jedisct1/repos","events_url":"https://api.github.com/users/jedisct1/events{/privacy}","received_events_url":"https://api.github.com/users/jedisct1/received_events","type":"User","site_admin":false},"created_at":"2018-02-17T13:44:56Z","updated_at":"2018-02-17T13:44:56Z","author_association":"OWNER","body":"It doesn't make any difference from a security perspective, but it can be generalized.\r\n\r\nThe same construction can be made with any key size and any hash function."}}
{"actor":{"display_login":"jedisct1"}}