> On Thu, May 21, 2015 at 07:36:04PM +0200, Bjorn Kuiper wrote: > > Hi, > > > > > > > > I'm having some problems using the otr_modify application from the > > otrlib toolkit. > > > > > > > > Could somebody explain to me where I can get the mackey that is needed > > as the first parameter? > > > > > > > > Assume I send the following text > > > > > > > > "hi bob, my name is alice" > > > > > > > > Which is encrypted into the following data message: > > > > > ?OTR:AAMD8E6ZSifXvlYAAAAAAQAAAAEAAADAD2DA/+dQWOE0SbzhRlF9M > NezfZxG+qNXz > > GaJ65W > > > j3qr/72f1MSx1lSxJ2hZ0HX22rFbO3ctAY97iMNwVoZGW7WRj4Fy3JZWZ8ATxL > OSzX26DF > > 9Ft/O1 > > > h8Ndu5gzVYoUsXAj0Q+UCkMD9jR2Pv6/ykLhx1eHyznpIFDxkExblcdOcFAHZX > 8iWeIocu > > h8Ndu5gzVYoUsXAj0Q+CrsF8A > > > oRMPTHsB3x8XXergQ6XOzOUQTNjyBSdoV46CFk3qWGJy8OC3HQPQhG4voP > 1wyvBUJAAAAA > > AAAAAE > > > AAAAZoCjmoJICwz+7CJZ//uMLWbrm9pT4ABiURY39QOGdMud4QQIA3gI1pX > h+KUIWAAAAAA==. > > > > > > > > Wouldn't the mackey be the key that I can retrieve using otr_parse, thus: > > 8dfd40e19d32e778410200de0235a5787e294216 ? > > No, that's the MAC tag, not the MAC key. > > > Or would it be the mackey that I would retrieve when re-establishing a > > new DH key and get it from the list of old mackeys? > > Indeed. There are two ways to get the MAC key. One is if you know the > private part of a DH key, in which case you can use otr_sesskeys to get it. > The other is if you have a transcripts containing later messages that contain > this key as an "old mackey", which you get with otr_parse. > > - Ian
So consider the attached private key pidgin file, the private key of __bob would be "2E3342837ACFB215EF502845CB48BB724762B950" whereas the public key of __alice would be "009D1F02172287D532DA187202FD752EB372AB8A16130927E9BE1B21453853544872E0126F0 8CB9F5BCB5345E5B83E62058663AD511CA601A59EEA73C8904C4B25915B3B8C3CE39CF108E1E 11F7AA4C258112554CD5A325C3A8613F9365586AAA0904B0FEBEFB6F643B9209D79180EEF319 D5A75EEE800D39C44A26CA672C38567". Running this through otr_sesskeys results in -- We are the high end of this key exchange. Our public key: c44ea24c97b2e231d3846f25d7336512f3492869fbd30a9a0051fe9abfcffb0e512bff9df3cc 88ae3c2d3291d5993957a254b422e0bea47897bbf0e37bd02d58c4baf891f99197a611d47891 ba827930a1dbce7fb4b591c833c71913f9489554ebb29a1f4b5b5b7bbbc86c08f5995af4ab90 854a0d422935ceed4cf35eb6c366464a224b6522ae1b450f09c92a3a874f19c05a9e6a755ee0 7f432119d5555db10651a926f2dd595d2fc60ccfe30ec0b5ac3d730b22c2af8fd662510ebf87 6d0a Session id: b3c7046430ea2e0c1e29bb1b74bab8c7c5e82608 Sending AES key: 38433fc99476c6dec00905700876740b Sending MAC key: bb307c86b269201b33e8f4606f8f541d8a11c3bd Receiving AES key: a3d04c132c68a9697d1092225304d097 Receiving MAC key: d4def44ed4178c84a693a14516d344b7917b23a2 -- Where our focus is on the receiving MAC key. We use this MAC key to modify our message that we send to __alice, saying "hoi alice": ?OTR:AAMDJ9e+VvBOmUoAAAAAAQAAAAEAAADA/QzMtslPdMiwOhStWZG5HQ7h9tdpb9KpM7R57Gv MHHGDbFH1VDc74L3OHJdRprso5ZLsaQK9Rx3s7ZFIh6ubbDvsm/HPUCoZGwe1fadGV7d/v9+Eyg/ 0jnjh0lGVDIT+W6d5Ia0EmHIzS9G6hsAugpK9Pk370JTL0bSaJIyzWYeZamSo4+OwJcusmiKrfWC 15KiqGKWn0v29UYCpjrrgIlTj96Wmgo0yCFg+IEbCpssK0uSRa33kyqQTnpLthBjqAAAAAAAAAAE AAAAKSrXNbc4fKYnZctVOW6P8z1koqGmSqMqRM+1o18P3AAAAAA==. Thus running otr_modify as follows -- $ ./otr_modify.exe d4def44ed4178c84a693a14516d344b7917b23a2 alice bjorn 4 ?OTR:AAMDJ9e+VvBOmUoAAAAAAQAAAAEAAADA/QzMtslPdMiwOhStWZG5HQ7h9tdpb9KpM7R57Gv MHHGDbFH1VDc74L3OHJdRprso5ZLsaQK9Rx3s7ZFIh6ubbDvsm/HPUCoZGwe1fadGV7d/v9+Eyg/ 0jnjh0lGVDIT+W6d5Ia0EmHIzS9G6hsAugpK9Pk370JTL0bSaJIyzWYeZamSo4+OwJcusmiKrfWC 15KiqGKWn0v29UYCpjrrgIlTj96Wmgo0yCFg+IEbCpssK0uSRa33kyqQTnpLthBjqAAAAAAAAAAE AAAAKSrXNbc4fKYnZctVOW6P8z1koqGmSqMqRM+1o18P3AAAAAA==. MAC does not verify: wrong MAC key? -- Which fails. Can you point me to my mistake? Thank you! Greetings Bjorn
otr.private_key
Description: Binary data
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