> For the complete documentation index, see [llms.txt](https://sgx101.gitbook.io/sgx101/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sgx101.gitbook.io/sgx101/sgx-security/branch-shadowing.md).

# Branch Shadowing

### Introduction

Another unique class of side-channel attacks in the SGX settings is branch-prediction-based attacks. By exploiting the branch predictor, the attacks infer the states (taken or non-taken) of branches executed by an enclave. This section demonstrates the attack.

### Branch Shadowing

This video shows how the branch shadowing attack can extract RSA private key bits

* Target code: Sliding window exponentiation of **mbedTLS**
* Attack code: We modified Linux SGX SDK to run our shadow code
* Kernel log: Our attack code prints the output of LBR via `dmesg`

{% embed url="<https://youtu.be/R_C0rfbg3p8>" %}

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