Keeping secret keys secret in open systems

Security of cryptographic keys stored on an untrusted host is a challenging task. Casual storage of keys could lead to an unauthorized access using physical means. If an adversary can access the binary code, the key material can be easily extracted using well-known key-finding techniques. This paper proposes a new technique for securing keys within software. In our proposed technique, we transform keys (randomly generated bit-strings) to a set of randomized functions, which are then compiled and obfuscated together to form a secure application. When the keys are required at the run-time, an inverse transform is computed by the application dynamically to yield the original bit-strings. We demonstrate that our technique resists attacks by many entropy based key finding algorithms that scan the host´s RAM at run-time.