Oblivious RAM (ORAM) is a cryptographic technique that hides which memory locations a program reads or writes, not just the data it stores. To an outside observer, the access pattern looks random or uniform, making it harder to infer what the software is doing from repeated reads and writes.
This matters in cyber security because access patterns can leak sensitive information even when content is encrypted. A database query, contact lookup, or key search may reveal relationships, interests, or user behavior through timing and location of memory access. ORAM is used in privacy-preserving systems, secure enclaves, and protected services to reduce metadata leakage. The tradeoff is overhead: ORAM typically adds latency, bandwidth, and implementation complexity, so defenders use it where privacy is worth the cost.