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--- pgpfan:tpp [2023/02/10 17:21] – Secret not needed for encryption in PK system. b.walzer
+++ pgpfan:tpp [2024/05/02 13:39] (current) – We have a reference now b.walzer
@@ Line 111: / Line 111: @@
 >Even if you do, the new SEIP packet format is close enough to the insecure SE format that you can potentially trick readers into downgrading; ...
-We have a problem here. The juxtaposition of the non sequitur about chopping off the last 22 bytes makes it seem that that is all that is required to downgrade the MDC. Some digging reveals that this is actually quite difficult and has a very low chance of success((Discussion:[[https://github.com/google/end-to-end/issues/161|No warning on decrypting Tag 9 (no integrity protection) packets]], Exploit code:[[https://gist.github.com/coruus/85dea6eb82897044f65d]])). We can be charitable here and assume that the author simply did not do any research but this is very misleading.
+We have a problem here. The juxtaposition of the non sequitur about chopping off the last 22 bytes makes it seem that that is all that is required to downgrade the MDC. Some digging reveals that this is actually quite difficult and has a very low chance of success(1 out of 65536)((Discussion:[[https://github.com/google/end-to-end/issues/161|No warning on decrypting Tag 9 (no integrity protection) packets]], Exploit code:[[https://gist.github.com/coruus/85dea6eb82897044f65d]])). This still leaves the message damaged enough that most implementations will simply blow up with an error. These ideas about the MDC seem to have come from a particularly hard to follow section of the EFAIL paper(([[pgpfan:legends|Misleading Legends Caused by EFAIL]])).
 >Trevor Perrin worked the SEIP out to 16 whole bits of security.