If I know your salt, I can "De-Hash" bcrypts faster than I can any of the "weird" combinations. Because there are libraries for doing so on ATI cards.
If you do something weird a script kiddie can't just pull code off the web and attack it. You want to see who can offline crack a set of 1M users? Your bcrypt list vs my "Weird" You don't even have to give me the salt I'll have 10k of those cracked in the first 72 hours. 10 to 1 odds you won't get through mine without my source code in my life time. -Brandon Wirtz PS I don't usually do the "trust me I'm far more evil" but FBI, Homeland Security, and the CIA have been to my doorstep for things I have defeated, documented, or built to keep from being defeated. The first time I was in 3rd grade. From: google-appengine@googlegroups.com [mailto:google-appengine@googlegroups.com] On Behalf Of Nick Johnson Sent: Monday, November 14, 2011 3:56 PM To: google-appengine@googlegroups.com Subject: Re: [google-appengine] Help resolve massive performance regression in 2.7 vs 2.5 runtime No! Please, please don't do this. Obscurity is no substitute for security. 1) Bcrypt or similar is not 'overkill' no matter who you are. Users reuse passwords, and they're entitled to the best protection you can reasonably provide them. 2) Bcrypt is not there to protect against online attacks, it's there to protect against offline attacks, where an attacker obtains your hashed and salted passwords. 3) Doing "something weird" is security through obscurity. Do not base your security on your attacker not knowing what you did. Really, really don't just concatenate salts to the beginning or end of the password. 4) Both MD5 and SHA1 are merkle-damgard construction hashes (http://en.wikipedia.org/wiki/Merkle%E2%80%93Damg%C3%A5rd_construction). As a result, the concatenation of several hashes is no more secure than the most secure of the individual hashes. -Nick Johnson On Sun, Nov 13, 2011 at 2:58 PM, Brandon Wirtz <drak...@digerat.com> wrote: Unless you are protecting Medical records bcrypt is overkill if you do some reasonably smart things like "Failed logins from IP >9" Or, if you just do something weird to the password BEFORE you SHA it. Like interleave the user name in the password, Salt1 + UpSaEsRsNwAoMrEd + Salt2 Or Pick 2 Hash's SHA(pass) + Md5(pass) Don't want to store all that string length? Odd Characters from Sha(Pass+salt) + Even Characters from MD5(Pass+Salt) Uniqueness of the method is more important than the method. -----Original Message----- From: google-appengine@googlegroups.com [mailto:google-appengine@googlegroups.com] On Behalf Of Brian Quinlan Sent: Saturday, November 12, 2011 6:58 PM To: google-appengine@googlegroups.com Subject: Re: [google-appengine] Help resolve massive performance regression in 2.7 vs 2.5 runtime Hi Pol, On Sun, Nov 13, 2011 at 1:48 PM, Pol <p...@everpix.net> wrote: > Hi, > > Since switching to 2.7 runtime, logging in to http://www.everpix.com > went from about a second to anywhere from 15s to 60s. I tracked it > down to this single password checking line: > > from bcrypt import bcrypt > bcrypt.hashpw(password, self.password_hash) == self.password_hash What value are you using for "threadsafe" in your app.yaml? How large is self.password_hash? Cheers, Brian > This comes from "a native Python implementation of the py-bcrypt > package from http://www.mindrot.org/projects/py-bcrypt/"; grabbed from > here: https://github.com/erlichmen/py-bcrypt. > > So what's happening here and how can we fix this? > > Thanks, > > - Pol > > -- > You received this message because you are subscribed to the Google Groups "Google App Engine" group. > To post to this group, send email to google-appengine@googlegroups.com. > To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com <mailto:google-appengine%2bunsubscr...@googlegroups.com> . > For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com <mailto:google-appengine%2bunsubscr...@googlegroups.com> . For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com <mailto:google-appengine%2bunsubscr...@googlegroups.com> . For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en. -- Nick Johnson, Developer Programs Engineer, App Engine -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
