Terminology breakdown for noob

[bkingtu83]

Hey guys

I've been researching this site the past week or so and have found a lot of helpful tips and ideas that I will soon use. I currently have an iphone 4 32GB with ios 4.1. Previously had a 3GS 16 GB. Never jailbroke either, but am looking to jailbreak my 4.

I already know that there is currently no jailbreak for 4.1 so I'm not asking that (although a lot of ppl keep making new threads asking about it. common sense would tell you to read previous threads.)

But anyway, I'm getting accustomed to the terminology such as jailbreaking, cydia, winterboard, dfu, etc. etc. A few terms I am confused on that I see often are ssh or open ssh, shsh, and blobs. I kind of know that jailbreakers use open ssh to edit themes, but is that the same as shsh and blobs?

Thanks

 

[ulbador]

SHSH==BLOBS and are the signed signature blobs that Apple sends to the iPhone 4 when it is trying to determine whether you are allowed to install a firmware or not. Basically, by caching these somewhere (either on your local computer or on Cydia's servers), you are allowed to install firmware that Apple has otherwise said you are not allowed to.

This can be important at a time like right now, when 4.1 is the only firmware Apple is allowing to be installed on devices. 4.1 is unjailbreakable, but if you have your firmware SHSH on file for 4.0.1, the last version that was jailbreakable,that means you will always be able to restore to it. Even if you don't jailbreak, it is important to download TinyUmbrella and get these BLOBS cached somewhere. Sometimes Apple breaks new firmwares so it's important to keep the ability to downgrade.

You can only cache these SHSH or BLOBS when Apple is signing them. Which means unless your phone was either jailbroken with Cydia installed or had TinyUmbrella run at the time when Apple was allowing 4.0.1 to be installed, you will never be able to go back to that version.

OpenSSH is just command-line based remote access software that has an FTP component built into it. With SSH installed, you can access and change files on your phone directly.

 

[maturola]

SSH = Secure Shell: Network protocol that allow data transfer and machine to machine communication using a secure channel (encrypted), it primarily used on Linux/UNIX system and it was design to replace unsecured protocoles like Telnet.

OpenSSH = same protocol, licensed under the GNU (Source is public)

SHSH Blobs = Those are a series of files with Extension .shsh (yield the name), this are signature files which is verified against Apple Server. Apple only sign those files with the most current firmware release and them make iTunes check for it, so that way they force your to install the most current firmware (by design they didn't count on users saving these files locally)

 

[thelatinist]

To clarify, if you install OpenSSH on your iPhone after it is jailbroken, you can use software such as Cyberduck or SmartFTP on your computer to browse its filesystem and upload files over a WiFi network.

 

[bkingtu83]

oh ok. so essentially, with SSH i can change things on the lock screen and home screen (ex: the icon picture for an app, the grey button on the lock screen, etc?)

and i'll have to dig deeper on the blobs, but from what you guys are saying its pretty much a way for apple/itunes to verify that the device has the latest firmware? and if not, then make you update to prevent the opportunity to jailbreak?

 

[bkingtu83]

To clarify, if you install OpenSSH on your iPhone after it is jailbroken, you can use software such as Cyberduck or SmartFTP on your computer to browse its filesystem and upload files over a WiFi network.

oh ok. cool. thanks

 

[TMar]

oh ok. so essentially, with SSH i can change things on the lock screen and home screen (ex: the icon picture for an app, the grey button on the lock screen, etc?)

and i'll have to dig deeper on the blobs, but from what you guys are saying its pretty much a way for apple/itunes to verify that the device has the latest firmware? and if not, then make you update to prevent the opportunity to jailbreak?

SSH is just a protocol, same as ftp and http's are protocols. The same as using finder or explorer to view and manipulate the files locally or remotely. Edit, rename, copy, paste, move, delete. It's just named after the protocol it uses but in essences a program uses the connection to do basic file management.


SHSH blobs are just yea or nay response from Apple, while this is very dumbed down so is Apple's implementation of it. While Apple uses a strong encryption key we don't need to try to decrypt it, because it never changes for a given device on a given firmware. Example, my 3gs on 4.1. I can request a response for 4.1 a million times and I will get the exact same encrypted response 1 millions times. They might as well just 1 for yes or a 0 for no.

We are able to store a copy of the yea's to use later when Apple is saying nay. Cydia has a server the acts like Apple's, except itunes is dumb deaf and blind. It doesn't check to make sure it's talking to Apple's server so it will accept a response from any server we point it too.

 

[philip in al]

Very helpful to me also. Thanks guys

 

[Applejuiced]

Good info in this thread, all new to jailbreaking should read.

 

[murdercitydevil]

I always wondered why Apple prevents users from downgrading...really, what is the point? I can't imagine that it's because they're so concerned with jailbreaking. And if they wanted to do it right, why not at the very least fix itunes so it ONLY accepts responses from apple's server? Just seems so utterly backwards and nonsensical to me.

 

[bytethese]

I always wondered why Apple prevents users from downgrading...really, what is the point? I can't imagine that it's because they're so concerned with jailbreaking.

Security. They want to do their best to ensure their products are the least susceptible to bugs, etc and by not letting someone downgrade to a potentially "broken" software version, it improves security overall.

 

[TMar]

I always wondered why Apple prevents users from downgrading...really, what is the point? I can't imagine that it's because they're so concerned with jailbreaking. And if they wanted to do it right, why not at the very least fix itunes so it ONLY accepts responses from apple's server? Just seems so utterly backwards and nonsensical to me.

Because most updates include security updates/bug fixes. Apple could have easily made it impossible to store the SHSH blobs for later use in a number of different ways. Why they didn't is a huge mystery.