White-box cryptography

White-Box Cryptography is emerging as a key technology to combat hacking and intellectual property (IP) theft in unsecure or untrusted environments.

> Download our white paper on White-Box Cryptography.

Software developers seeking to reduce their code’s vulnerability to attack should understand the benefits of White-box cryptography and what to look for when selecting a solution.

The need for white-box cryptography

Popular trusted ciphers like RSA and AES were not designed to operate in environments where their execution could be observed. In fact, the standard cryptographic model is that communications endpoints and computing platforms are assumed to be trusted. If the target device resides in a hostile environment, then the cryptographic keys may be directly visible to an attacker. An attacker may be able to monitor the application and extract one or more cryptographic keys embedded or generated by the application.

This is a common problem for PCs, set top boxes and other devices where DRM, conditional access or other security sensitive applications are involved. Hackers monitor standard cryptographic APIs or memory and simply grab keys when exposed. Two recent examples of successful memory-based key lifting attacks are the AACS/BackupHDDVD hack that lifts the AACS keys from memory to enable the BackupHDDDVD tool to copy the disc, and the FairUse4WM utility that removes the DRM from protected Windows Media content.

What is white-box cryptography?

In traditional cryptography, a black-box attack describes the situation where the attacker tries to obtain the cryptographic key by knowing the algorithm and monitoring the inputs and outputs, but without the execution being visible. White-box cryptography addresses the much more severe threat model where the attacker can observe everything, can access all aspects of the target system/application, and may have the black-box knowledge of the crypto algorithm.

Black-box attack

• Attacker knows algorithm
• Watches inputs and outputs
• Controls input text
• No visibility of execution

White-box attack

• Attacker can observe everything
• Attacker knows algorithm
• Watches inputs, outputs, intermediate calculations
• Controls input text
• Full visibility into Memory (debuggers and emulators)

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More information about white-box cryptography is available in the position paper Understanding the Advantages of Cloakware White-Box Cryptography.

> Download our white paper on White-Box Cryptography.