SHSH blobs (Signature HaSH blobs) are essentially "digital tickets" that Apple uses to control which versions of iOS can be installed on your device What are SHSH Blobs? A Security Gate
: When you restore or update an iPhone, your device sends a request to Apple's servers. Apple responds with a unique cryptographic signature (the "blob") that authorizes the installation of that specific iOS version. Device-Specific : Every blob is unique to a single device's
(Exclusive Chip ID). You cannot use someone else’s blobs to restore your own device. Time-Sensitive
: Apple only "signs" (issues blobs for) the most recent versions of iOS. Once Apple stops signing an older version, you can no longer get the blobs for it from their servers. Why Should You Care? Downgrading
: If you save your blobs while an iOS version is still being signed, you can use tools like FutureRestore
to downgrade or "sidegrade" to that version later, even after Apple has stopped signing it. Jailbreaking
: Most jailbreaks are version-specific. Saving blobs is your insurance policy; if you accidentally update or your phone crashes, blobs allow you to return to a jailbreakable version. Key Technical Terms iOS Guide: How To Downgrade And Save SHSH Blobs!
The following essay explores the technical underpinnings, historical significance, and eventual decline of SHSH blobs in the context of iOS security and the jailbreaking community. The Digital Passport: The Role of SHSH Blobs in iOS History
In the world of iOS device customization, few technical terms carry as much weight as the "SHSH blob." For a generation of enthusiasts, these small files represented the difference between digital freedom and being locked within Apple’s "walled garden." Formally known as Signature HaSH
blobs, they are essentially unique digital certificates that Apple uses to verify and authorize the installation of iOS firmware on a specific device. While they may seem like a minor technical detail, SHSH blobs were the frontline in a decade-long struggle between Apple’s security engineers and the jailbreaking community. The Mechanics of the "Signing Window"
To understand SHSH blobs, one must first understand Apple's firmware signing process. Whenever a user attempts to restore or update an iPhone or iPad, the device does not simply run the installer. Instead, it sends a request to Apple’s servers containing its unique
(Exclusive Chip ID) and the version of iOS it wants to install.
If Apple still supports that version, its servers return an SHSH blob—a digital signature that "greenlights" the installation for that specific hardware. Because these blobs are unique to each individual device’s ECID, a blob saved for one iPhone cannot be used on another. When Apple releases a new iOS version, they typically stop "signing" older versions after a few weeks, effectively closing the "signing window" and preventing users from ever going back to an older firmware. The Golden Age of Downgrading
During the early years of iOS (specifically before iOS 5), SHSH blobs were the holy grail for jailbreakers. Software like TinyUmbrella
allowed users to "save" their blobs while a firmware version was still being signed. Once saved, these blobs could be replayed to a device later, tricking it into thinking Apple was still authorizing an older, jailbreakable version of iOS even after the official signing window had closed.
This era fostered a vibrant community where users meticulously backed up their digital "blobs" as insurance. If a new update proved unstable or broke a beloved jailbreak tweak, having a saved SHSH blob was the only way to "downgrade" and regain a stable environment. The Introduction of the APTicket and Nonces
Apple eventually responded to this loophole by evolving its security architecture. With the release of iOS 5, they introduced the and a security measure known as a
—a random, one-time-use number generated by the device for every restore request.
The nonce made traditional SHSH blobs much harder to use because a saved blob would only work if the device generated the exact same random number during a future restore. While the community developed tools to "freeze" or set these nonces (nonce-setting), the process became significantly more technical and less reliable for the average user. The Modern Landscape: End of an Era
Today, the relevance of SHSH blobs has diminished significantly. On modern devices with A12 chips and newer, Apple has implemented advanced hardware-level protections (like the Secure Enclave and Cryptex) that make traditional blob-based downgrading almost impossible for the general public. For most modern iPhone users, once a firmware version is no longer signed, it is gone forever.
Despite their declining utility, SHSH blobs remain a fascinating chapter in computer security history. They represent a period when individual users and developers found creative ways to bypass centralized control, turning a security feature meant for restriction into a tool for digital autonomy. For many, the practice of "saving blobs" wasn't just about software—it was a rite of passage in the secret history of mobile computing. used to save blobs, such as TSS Checker , or discuss the current status of jailbreaking on newer iOS versions? jeweled platypus · britta's blog 18 Nov 2016 —
In the world of iOS customization, SHSH blobs (Signature Hash Blobs) are essentially the "digital keys" Apple uses to control which versions of iOS you can install on your device. What are SHSH Blobs?
Technically called APTickets, an SHSH blob is a unique digital signature generated by Apple's servers.
Device Specific: Every blob is unique to your specific device's ECID (Exclusive Chip ID). You cannot use someone else's blobs for your phone.
Version Specific: Each blob is tied to a specific iOS version and build ID.
The "Signing" Window: Apple only issues these signatures for "signed" versions of iOS—typically the latest version and sometimes the one immediately preceding it. Once Apple stops signing a version, their servers will no longer provide the blob for it. How They Work
When you try to restore or update your iPhone via iTunes, the software contacts Apple's Tatsu signing server. It sends your device's details, and the server returns an SHSH blob. If the signatures in that blob match the firmware you are trying to install, the restore proceeds; if not, you get an error.
By "saving" these blobs while a version is still being signed, you effectively store a copy of Apple's permission. Later, even after Apple has stopped signing that version, you can use tools like FutureRestore to "replay" that saved signature and trick your device into accepting the older firmware. The Modern Catch: SEP and Cryptex shsh blobs
While saving blobs was a "get out of jail free" card in the early days of jailbreaking, Apple has introduced more complex security layers that make them harder to use on newer devices (A11 and later):
SEP (Secure Enclave Processor): This is a separate chip handling security (like FaceID/TouchID). It requires its own signature. If the currently signed SEP is incompatible with the older iOS version you want to downgrade to, the restore will fail or break your biometric security.
Cryptex: Introduced in iOS 16, this adds another layer of unique nonces (random numbers) that further complicates the restoration process.
Nonces: Modern blobs often require a specific "Nonce" (a number used once). Unless your device is jailbroken or you have found a way to "set" your device's nonce to match your blob, the blob is often useless. How To Check What SHSH Blobs You Have - iPhone, iPod, iPad
SHSH Blobs: Your Digital "Ticket" to iOS Freedom In the world of iOS customization, SHSH blobs
(Signature Hash Blobs) are the holy grail for users who want control over their device's software version. Essentially, they are unique digital signatures that Apple uses to verify and authorize the installation of iOS on your iPhone, iPad, or iPod Touch. What is an SHSH Blob? Technically known as System Software Authorization
, an SHSH blob is a "ticket" generated by Apple's servers. It consists of: Device ECID: Your device's unique hardware identification number. iOS Version: The specific firmware version you are trying to install.
A "number used once" to randomize the signature for security.
Without a valid blob for a specific version, Apple’s servers will reject the installation, effectively forcing you to stay on (or upgrade to) the latest "signed" version. Why They Matter: The Power of Downgrading
Apple typically stops "signing" older iOS versions within days or weeks of a new release. Once signing stops, you cannot officially go back. However, if you saved your blobs
while that version was still being signed, you can use tools like FutureRestore
to "spoof" Apple's servers and downgrade or restore to that specific version. This is critical for: Jailbreaking:
Staying on a lower, vulnerable firmware version where a jailbreak is available. Performance:
Reverting to a faster iOS version if a new update slows down an older device.
Developers often need specific versions to test app compatibility. How to Save Your Blobs You can only save blobs for iOS versions that Apple is currently signing
. You do not need to be jailbroken to save them. Popular tools include:
george-lim/blobsaver: A beautiful & organized TSSSaver client for iOS.
(short for signature hash blob) is a digital signature that Apple uses to verify and authorize iOS installations on specific devices.
By "saving" these blobs while Apple is still signing a specific iOS version, you create a "golden ticket" that may allow you to downgrade or restore to that version later, even after Apple has stopped signing it. Key Concepts Device-Specific : Every blob is unique to a device's
(Exclusive Chip ID). You cannot use someone else’s blobs to restore your own phone. The Signing Window : You can only save blobs for iOS versions that Apple is currently signing
. Once Apple "closes" a version, you can no longer fetch its blobs from their servers. Onboard Blobs
: In some cases, if your device is currently running an unsigned version, you can use specialized tools to dump the "onboard" blobs directly from the device's memory. How to Save SHSH Blobs
The process generally requires connecting your device to a computer and using a dedicated tool.
An SHSH Blob (Signature HaSH) is a unique digital signature that Apple uses to verify the firmware version you are trying to install on your device. Every time you restore or update your iPhone via iTunes or Finder, the software sends a request to Apple’s servers. Apple then "signs" this request with a blob specific to your device's unique ID (ECID) and the specific iOS version.
Without this digital signature, your device will refuse to boot or install the operating system. Why Do They Matter?
Apple typically only "signs" the most recent version of iOS (and sometimes the one immediately preceding it). This is known as the signing window. Once Apple stops signing an older version, it becomes impossible for a standard user to downgrade to it. SHSH Blobs are essential for:
Downgrading iOS: If a new update makes your phone slow or you dislike the features, you can only go back to an older version if you have saved the blobs for that specific version while it was still being signed. SHSH blobs (Signature HaSH blobs) are essentially "digital
Jailbreaking: Many jailbreaks are only compatible with specific, often older, versions of iOS. Saving blobs allows you to "hop" to those versions later, even after Apple has closed the signing window. How the Process Works
The Challenge: Your device sends its ECID and the firmware version to Apple's servers.
The Response: Apple checks if that version is still "open." If it is, they send back an SHSH blob.
The Validation: Your device's bootloader checks this blob. If it matches, the installation proceeds. How to Save SHSH Blobs
You cannot save blobs for a version of iOS that Apple is no longer signing. You must be proactive.
Tools: Popular community tools like TSS Saver (online) or Blobsaver (desktop application) can automatically fetch and store these for you.
Frequency: It is a best practice among enthusiasts to save blobs every time a new iOS version is released, regardless of whether you plan to update or not. The "Nonce" Problem
Starting with iOS 5, Apple introduced a nonce—a random number generated for each restore request. This means you can't just "replay" an old blob; the blob must match the specific nonce your device is currently expecting. Advanced tools (like FutureRestore) are often required to manage nonces and successfully use your saved blobs for a downgrade. Engineering Security - School of Computer Science
SHSH blobs (officially known as APTickets) are unique digital signatures generated by Apple to control which iOS versions you can install on your device. Since Apple typically only "signs" the latest firmware to prevent downgrading to older, potentially vulnerable versions, these blobs act as a "golden ticket" to bypass those restrictions later. Why They Matter
The Downgrade Key: If you want to move from a newer iOS version back to an older one (for better performance or a specific jailbreak), you need the SHSH blobs for that older version.
Device-Specific: Every blob is tied to your device's unique hardware ID (ECID). You cannot use a friend's blobs on your phone.
Time-Sensitive: You can only save blobs for a specific iOS version while Apple is still actively signing it—usually for just a few weeks after a new update drops. How to Save Them
You don’t need to be jailbroken to save blobs, but you do need to do it immediately while the window is open. Common community tools include:
The last thing Kaelen remembered was the cold. Not the biting cold of a winter wind, but the static, absolute zero of a boot loop. His iPhone, a silver slab that had held his life—photos of his daughter’s first steps, the voicemail from his late father, the novel he’d been writing in notes—was now a glowing brick. A white Apple logo stared at him from the dark, pulsing every few seconds like a dying heartbeat.
“It’s gone,” the tech at the mall kiosk said, not looking up from his magnifying glass. “The NAND is corrupted. Unless you have a time machine.”
Kaelen almost laughed. A time machine. That’s exactly what he needed.
That night, after his wife and daughter went to sleep, he found a forum. Not the glossy Reddit threads or YouTube tutorials, but a deep, phosphorescent-green text board that smelled of old code and desperation. The user was named Axiom_breaker.
“You don’t need a time machine,” the message read. “You need SHSH Blobs.”
Kaelen frowned. He’d jailbroken his iPod Touch back in 2010. He remembered the term—SHSH Blobs were tiny, useless cryptographic signatures Apple issued for each iOS restore. Like a wax seal on a letter, they proved a specific firmware version was “authorized.” Once Apple stopped signing an old version, those blobs became worthless. Digital ghost certificates.
“Worthless to Apple,” Axiom_breaker continued, as if reading his mind. “Valuable to us. They are the fingerprints of a moment. Your phone isn’t ‘bricked.’ It’s just forgotten which version of itself it’s supposed to be. You need to feed it its own memory.”
The instructions were absurd. Kaelen had to put his bricked phone into a custom DFU mode—not the usual one, but a hidden diagnostic state triggered by a rapid, off-rhythm sequence of button presses (volume up, volume down, power for 0.8 seconds, release, repeat). Then, instead of iTunes, he had to use a command-line tool called Tesseract, which didn’t restore firmware—it unpacked blobs.
His screen filled with hexadecimal waterfall. And then, something odd happened.
The white Apple logo on his phone flickered. It didn’t boot. Instead, the screen became a deep, oceanic blue. And floating in that blue were shapes.
Blobs.
At first, Kaelen thought his eyes were playing tricks. But no—these were three-dimensional, soft-edged, gelatinous forms of pure light. Each one was a different color: a pale, milky white; a bruised purple; a newborn green. They pulsed gently, synced to no rhythm he could feel.
On his computer monitor, the terminal output changed:
Extracting SHSH 11.2.6...
Blob contains: "Daddy, I took this picture of a squirrel!" [AUDIO HASH] The last thing Kaelen remembered was the cold
His heart stopped. That was his daughter’s voice. From a video he’d deleted two years ago to save space. The blob had preserved not the data, but the signature of the data—the cryptographic proof that the memory had once existed.
Extracting SHSH 12.0.1...
Blob contains: "Son, don't worry about the money. Just visit more." [VOICEMAIL HASH]
His father. The voicemail he’d lost when he switched carriers. The words themselves weren’t stored in the blob—only the hash, the unique fingerprint. But Axiom_breaker’s tool had a second function: reification. It could use the hash as a key to rebuild the memory from the residual electromagnetic traces left on the phone’s own logic board.
Kaelen typed the command. ./reify --blob=dad_voicemail.shsh
The iPhone’s speaker crackled. And then, distorted but unmistakable, his father’s voice:
“Hey champ. Just called to say I’m proud of you. Call me back when you can. Love you.”
Kaelen wept. Not from sadness, but from the sheer impossibility of it. These were not files. They were not backups. They were proofs of existence. Apple had designed SHSH Blobs to prevent downgrading, to lock users into the present. But what Axiom_breaker had discovered was their secret purpose: they were digital fossils. Tiny amber droplets trapping the fact that a moment had been real.
He spent the night extracting. The white blob contained the first photo he’d ever taken on that phone—a blurry shot of a rain-spattered window. The purple blob held a text argument with his brother, the one they’d made up from two days later—the hash preserved the raw emotion of the fight, even if the words were gone. The green blob was the strangest: it contained a three-second recording of his own laughter from a forgotten voice memo, a laugh he no longer recognized as his own.
When morning came, his phone was no longer a brick. It booted to the home screen, exactly as it had been the day before the crash. But something was different. In the corner of every photo, a tiny, translucent, jelly-like watermark shimmered—the ghost of the blob that had restored it.
He never found Axiom_breaker again. The forum disappeared. The Tesseract tool corrupted itself after one use. But Kaelen didn't mind. He had what he needed.
Years later, when his daughter asked why he kept four identical, broken iPhones in a lockbox, he just smiled.
“They’re not phones, kiddo. They’re tombs. And inside each one, there’s a little jellyfish that remembers everything.”
He never updated his iOS again. And every time Apple released a new version, he thought of all the people who clicked “Agree” without knowing what they were losing. Not their data.
Their blobs.
The small, soft, beautiful signatures of their own forgotten lives.
A solid technical feature about SHSH Blobs would focus on their role as the "digital fingerprint" required for the unauthorized installation of iOS firmware.
Here is a breakdown of the feature:
Even if you think you will never downgrade, save your blobs today. Use the TSS Saver website. It takes 30 seconds. One day, a jailbreak for your current version might drop after Apple stops signing it. If you have the blobs, you can use a tool like FutureRestore to jump back.
In the cat-and-mouse game between Apple’s security and user freedom, SHSH blobs are the mouse’s only insurance policy. Keep your tickets safe—you never know when you might want to go back to the old show.
Disclaimer: Modifying iOS firmware violates Apple’s EULA and may void your warranty. Always back up your data before attempting any restore with SHSH blobs.
For years, a small band of rebels known as "Jailbreakers" sought to roam free, returning to older, more flexible versions of the realm. To do this, they needed a magical artifact: the SHSH Blob. The Birth of a Blob
Every time a device wants to update or restore its firmware, it must ask the Signing Server for permission. The server responds with a unique digital signature—a "blob"—that is specifically tied to that one device's ECID (its unique hardware fingerprint). Without this signature, the device refuses to boot into that version of iOS. The Great Signing Window
The gatekeeper is fickle. It only hands out these signatures for the very newest versions of iOS. Once a new version is released, the "signing window" for the old one slams shut, often within just a week. After that, the signatures for that version vanish from the earth—unless someone has already caught one. The Quest for the Blobs
Wise travelers know they must "save their blobs" while the window is still open. They use specialized tools to trick the server into giving them a signature even if they aren't ready to use it yet:
TinyUmbrella: An ancient relic from the iOS 4 days that first allowed users to hoard these signatures.
TSS Saver & Blobsaver: Modern-day lanterns used to capture and store these digital keys for later. The Cat-and-Mouse Game How to save SHSH Blobs ios 15 | by Telegram Bot
Use: TinyUmbrella (pre-iOS 10) or iFaith.
SHSH blobs are cryptographic signatures Apple issues for each iOS firmware version and device. They’re used in the iTunes/Apple signing process to verify firmware installs. Because Apple only signs the latest allowed firmware, you normally can’t downgrade or restore to unsigned iOS versions.
SHSH blobs (Signature HaSH blobs) are small digital signatures issued by Apple to verify the authenticity of iOS firmware installations. They are central to Apple’s code-signing security mechanism. In the jailbreaking community, saving and replaying SHSH blobs allows advanced users to downgrade or restore devices to older, unsigned iOS versions—a process normally prevented by Apple. This report outlines the technical function, usage, limitations, and current relevance of SHSH blobs.