What are TTComp archive data files and how can i decrypt them?
Take a look at OTATrustUtilities, which is Apple's implementation of extracting data from the system keychain. Specifically the InitializeAnchorTable function looks at extracting the data from those two files. The certsIndex.data file is a Database Index file that contains an array which can be read using NSData, this contains a list of sha1 hashes and offsets. These offsets correspond to the start of the certificate data found in the certsTable.data file, so you can start reading from the offset to the end of the certificate. It is worth noting that an application which accesses these private files will not be accepted onto the AppStore and this should only really be used for personal use or jailbreak development.