# US 10,120,987 B2 · Device and method for executing protected iOS software modules

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- Number: US 10,120,987 B2
- Document ID: US10120987B2
- Status: Granted
- Kind: B2
- Application number: 15/374,372
- Filed: 2016-12-09
- Published: 2017-06-15
- Granted: 2018-11-06
- Earliest claimed: 2015-12-10
- Assignees: InterDigital CE Patent Holdings, SAS
- Applicants: Thomson Licensing
- Inventors: Antoine Monsifrot; Charles Salmon-Legagneur; Alain Durand
- Web page: https://patentgrep.com/patent/US10120987B2

## CPC

- G06F 21/14: against software analysis or reverse engineering, e.g. by obfuscation
- G06F 8/71: Version control (security arrangements therefor G06F21/57); Configuration management
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A device comprising a hardware processor and memory storing an application of an application package comprising a first version and a second version of the application, the first version being intended to be executed on a genuine device and the second version on a jailbroken device. The hardware processor determines a jailbreak status of the device, i.e. genuine or jailbroken and derives a key based on at least the jailbreak status. In case the device is genuine, the hardware processor deciphers using the key at least a first part of the first version and executes, the first version using the first deciphered part, for example a jump table used to execute CFG flattened code. In case the jailbreak status is jailbroken, the hardware processor deciphers using the key at least a first part of the second version and executes the second version using the second deciphered part, for example comprising executable instructions.

## Claims

### Claim 1

A method for executing code of an application of an application package comprising a first version and a second version of the application, the first version intended to be executed on a genuine device and the second version intended to be executed on a jailbroken device, the method comprising in a device:
determining by at least one hardware processor a jailbreak status of the device;
computing by the at least one hardware processor an integrity value for the code;
deriving by the at least one hardware processor a decryption key based on at least the jailbreak status and the integrity value; and
in case the jailbreak status indicates that the device is genuine:
decrypting by the at least one hardware processor using the decryption key at least a first part of the first version stored in a memory of the device to obtain a first processed part; and
executing, by the at least one hardware processor using the first processed part, the first version; and
in case the jailbreak status indicates that the device is jailbroken:
decrypting by the at least one hardware processor using the decryption key at least a second part of the second version stored in the memory to obtain a second processed part; and
executing by the at least one hardware processor the second processed part.

### Claim 2 (depends on 1)

The method of claim 1, wherein the at least first part comprises a jump table.

### Claim 3 (depends on 2)

The method of claim 2, wherein the jump table is used with Control Flow Graph flattened code.

### Claim 4 (depends on 2)

The method of claim 2, wherein the jump table is stored in a data section of the first version of the application.

### Claim 5 (depends on 1)

The method of claim 1, wherein the second part comprises enciphered executable instructions.

### Claim 6

A device for executing code of an application, the device comprising:
memory storing an application package comprising a first version and a second version of the application, the first version intended to be executed on a genuine device and the second version intended to be executed on a jailbroken device; and
at least one hardware processor configured to:
determine a jailbreak status of the device;
compute an integrity value for the code;
derive a decryption key based on at least the jailbreak status and the integrity value; and
in case the jailbreak status indicates that the device is genuine:
decrypt, using the decryption key, at least a first part of the first version stored in the memory of the device to obtain a first processed part; and
execute, using the first processed part, the first version; and
in case the jailbreak status indicates that the device is jailbroken:
decrypt, using the decryption key, at least a second part of the second version stored in the memory to obtain a second processed part; and
execute the second processed part.

### Claim 7 (depends on 6)

The device of claim 6, wherein the at least first part comprises a jump table.

### Claim 8 (depends on 7)

The device of claim 7, wherein the jump table is used with Control Flow Graph flattened code.

### Claim 9 (depends on 7)

The device of claim 7, wherein the jump table is stored in a data section of the first version of the application.

### Claim 10 (depends on 6)

The device of claim 6, wherein the second part comprises enciphered executable instructions.