||This article has multiple issues. Please help improve it or discuss these issues on the talk page.
|Initial release||February 2008|
|Stable release||1.1.8 / October 14, 2012|
|Available in||English, Italian, Spanish, Chinese, Greek, German, Hebrew, Dutch, Polish, Swedish, Arabic|
|License||Modified BSD License|
Cydia (pron.: //) is a software application for iOS that enables a user to find and install software packages on jailbroken iOS Apple devices such as the iPhone. It also refers to digital distribution platform for software on iOS accessed through Cydia software Some of the software packages available through Cydia are free, and some require purchasing.
Cydia is developed by Jay Freeman (also called "Saurik") and his company, SaurikIT. The name "Cydia" is an allusion to the Codling Moth, with a scientific name of Cydia pomonella, which is the proverbial "worm in the apple."
Purpose and function 
Cydia provides a graphical user interface to jailbroken users using Advanced Packaging Tool (APT) repositories to install software unavailable on the App Store. Cydia is based on APT, ported to iOS as part of Freeman's Telesphoreo project.
Software packages are downloaded directly to an iOS device, to the same location as Apple's pre-installed applications, the
/Applications directory. Jailbroken devices can also still buy and download apps normally from the official App Store.
Cydia can be installed during the process of jailbreaking an iOS device. Some Jailbreaking tools (each of them supporting a specific set of devices and iOS versions) install Cydia automatically, while others provide a choice to the user.
Software available through Cydia 
Cydia enables users to find and install open source packages as well as purchase modifications for jailbroken phone4G s. These modifications are based on a framework called MobileSubstrate which makes it relatively easy to install and update said modifications.
iOS "signature" feature 
Cydia caches the digital signatures called SHSH blobs used by Apple to verify restores of iOS (which Apple uses to limit users to only installing the latest version of iOS). Cydia's storage mechanism enables users to downgrade a device to a prior version of iOS by means of a replay attack. This means, for example, that a person with a jailbroken device who upgrades to a non-jailbreakable version of iOS can choose to downgrade back to a jailbreakable version.
iOS 5.0 and later versions of iOS implement an addition to the SHSH system, a random number (a cryptographic nonce) in the "APTicket", making it more difficult to perform a replay attack.[dubious ]
In August 2009, Wired reports that Freeman claimed about 4 million, or 10 percent of the 40 million iPhone and iPod Touch owners to date, have installed Cydia."
On December 15, 2010, SaurikIT filed a dispute with world intellectual property organization against Cykon Technology Limited of Kowloon, Hong Kong over the rights to the domain name "Cydia.com", which was registered by its owner Cykon in 2002. SaurikIT contended that Cykon registered the domain name in bad faith and the domain name incorporates SaurikIT's trademark. SaurikIT initially attempted to purchase the domain, then demanded Cykon to forfeit the domain at cost asserting trademark rights followed by bringing a WIPO proceeding. The complaint was denied by WIPO.
As of April 2011, Cydia had a $10 million in annual revenue and 4.5 million weekly users and according to Freeman $250,000 net annual profit.
On May 14, 2013, Cydia Substrate for the Android operating system was released.
- "Saurik's Homepage". Retrieved August 4, 2010.
- Jack Loftus (September 11, 2010). "Largest iOS Jailbreak App Stores Become One After Cydia Acquires Rock". Gizmodo. Retrieved August 2, 2011.
- Chris Foresman (December 13, 2010). "iPhone jailbreaker set to bring Cydia to Mac OS X". Infinite Loop. Ars Technica. Retrieved August 2, 2011.
- Jay Freeman (saurik) (February 2008). "Bringing Debian APT to the iPhone". saurik.com. Retrieved August 2, 2011.
- Adam Dachis (March 14, 2011). "How to Get the Most Out of Your Jailbroken iOS Device". Lifehacker. Retrieved August 2, 2011.
- Jenna Wortham (May 12, 2009). "Unofficial Software Incurs Apple's Wrath". The New York Times. Retrieved August 2, 2011.
- Michael Rose. "Cydia Store now open for jailbreak app sales". The Unofficial Apple Weblog. Retrieved 2009-08-02.[dubious ]
- Adam Dachis (April 25, 2011). "Save Your iDevice’s SHSH to Avoid Losing the Ability to Jailbreak". Lifehacker. Retrieved August 2, 2011.
- Jay Freeman (saurik) (September 2009). "Caching Apple's Signature Server". saurik.com. Retrieved July 28, 2010.
- Nat Futterman (May 25, 2010). "Jailbreaking the iPad: What You Need to Know". Geek Tech. PCWorld. Retrieved August 2, 2011.
- Oliver Haslam (June 27, 2011). "iOS 5 Will Halt SHSH Firmware Downgrades On iPhone, iPad, iPod touch". Redmond Pie. Retrieved November 12, 2011.
- Erica Sadun (February 28, 2008). "Debian-style installation arrives on iPhone". The Unofficial Apple Weblog. Retrieved September 24, 2011.
- Brian X. Chen (August 6, 2009). "Rejected By Apple, iPhone Developers Go Underground". Wired. Retrieved August 2, 2011.
- Steven Sande (September 12, 2010). "Alliance of the jailbreakers: Cydia acquires Rock". The Unofficial Apple Weblog. Retrieved August 2, 2011.
- Jay Freeman (saurik). "Cydia += Rock Your Phone?". Cydia.
- WIPO case
- iPhone jailbreak App Store loses domain dispute for cydia.com Domainnamewire.com
- Ian Shapira (April 6, 2011). "Once the hobby of tech geeks, iPhone jailbreaking now a lucrative industry". The Washington Post. Retrieved August 2, 2011.
- 2011 8 22 Domainnamewire.com
- The Next Web
- "Cydia Substrate".