{"action":"opened","issue":{"url":"https://api.github.com/repos/yahoo/end-to-end/issues/31","labels_url":"https://api.github.com/repos/yahoo/end-to-end/issues/31/labels{/name}","comments_url":"https://api.github.com/repos/yahoo/end-to-end/issues/31/comments","events_url":"https://api.github.com/repos/yahoo/end-to-end/issues/31/events","html_url":"https://github.com/yahoo/end-to-end/issues/31","id":64891873,"number":31,"title":"Support for outdated, weak, and dangerous parts of OpenPGP","user":{"login":"coruus","id":972974,"avatar_url":"https://avatars.githubusercontent.com/u/972974?v=3","gravatar_id":"","url":"https://api.github.com/users/coruus","html_url":"https://github.com/coruus","followers_url":"https://api.github.com/users/coruus/followers","following_url":"https://api.github.com/users/coruus/following{/other_user}","gists_url":"https://api.github.com/users/coruus/gists{/gist_id}","starred_url":"https://api.github.com/users/coruus/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/coruus/subscriptions","organizations_url":"https://api.github.com/users/coruus/orgs","repos_url":"https://api.github.com/users/coruus/repos","events_url":"https://api.github.com/users/coruus/events{/privacy}","received_events_url":"https://api.github.com/users/coruus/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-03-28T03:03:35Z","updated_at":"2015-03-28T03:03:35Z","closed_at":null,"body":"This plan for deprecation has been reviewed and approved by our\r\n\"consulting cryptographers,\" Payman Mohassel and Juan Garay,\r\nboth of Yahoo Labs.\r\n\r\n## Support removed\r\n\r\n**Tag 9 packets.** Yahoo and Google have both already deprecated and\r\nremoved support for Tag 9 (symmetrically encrypted) packets.\r\n\r\nThese packets provide unauthenticated encryption and -- if supported\r\n-- can be used in a downgrade attack **for senders who only use SEIPD\r\npackets**. See [encrux][encrux] for details.\r\n\r\n## ASAP\r\n\r\nYahoo and GnuPG (as of version 2) have both already deprecated V3\r\npublic keys for any use. We recommend that other implementations do\r\nthe same.\r\n\r\n## By May 1, 2015\r\n\r\nYahoo has deprecated, and intends to disable support for all uses, of\r\nthe following algorithms specified for use with OpenPGP v4:\r\n\r\n- Asymmetric algorithms, unless > 3070 bit key length: RSA-ES, ELG-E.\r\n- Asymmetric algorithms, generally: RSA-E, RSA-S, DSA\r\n- Symmetric cipher algorithms: IDEA, TDES, CAST5, Blowfish, Twofish\r\n- Compression algorithms: ZLIB (the format provides no benefits over DEFLATE,\r\nand is more malleable)\r\n- Hash algorithms: MD5, SHA-1, RIPEMD160, SHA-2-224\r\n\r\nWe do not, at present, support any of the CAMELLIA algorithms or\r\nBzip2. It is unlikely that we will do so in future.\r\n\r\n## By September 1, 2015\r\n\r\n**Inconsistent combinations of primitives.** In particular, it is\r\nlikely that we will not support [RFC 6637][rfc6637] keys or packets unless they\r\nconform to the 128-bit or 192-bit subprofiles specified in that\r\ndocument. (End-to-End does not at present support P-521, but\r\nif we add support for curves over that field, we would support an\r\nanalogous \"256-bit\" subprofile.)\r\n\r\n**AES-128.** The [efficiency of multi-target attacks][djb] leaves [no safety\r\nmargin for cryptanalysis][twofish_comments]. The performance difference between AES-128\r\nand AES-256 on typical messages is negligible.\r\n\r\n## Eventually\r\n\r\nFinally, other things that may eventually result in messages or keys\r\nbeing treated as invalid:\r\n\r\n- A published public key that is more than 1 year old. (This is\r\nmainly taken care of by requiring > 3070 bit RSA keys...)\r\n- Signature by a public key which has ever signed a message or key\r\nusing MD-5 or SHA-1\r\n- Any literal data packet tag that is unusually formatted, or contains\r\na non-zero-length subpart\r\n- Any compressed data packet using a compression method other than\r\nalgorithm 0 (uncompressed)\r\n\r\n[djb_128bit]: http://www.ietf.org/mail-archive/web/cfrg/current/msg04824.html \"DJ Bernstein. Email 'Re: [Cfrg] matching AES security'\"\r\n[twofish_comments]: http://csrc.nist.gov/archive/aes/round2/comments/20000515-bschneier.pdf \"B Schneier et al. The Twofish team's final comments on AES selection.\"\r\n[encrux]: https://github.com/coruus/cooperpair/tree/master/encrux"}}