analyzing-ransomware-encryption-mechanisms

# Analyzing Ransomware Encryption Mechanisms ## When to Use - A ransomware infection has occurred and recovery requires understanding the encryption scheme used - Assessing whether decryption is possible without paying the ransom (implementation flaws, known decryptors) - Reverse engineering ransomware to identify the encryption algorithm, key derivation, and key storage mechanism - Developing a decryptor tool when a weakness in the ransomware's cryptographic implementation is identified - Classifying a ransomware sample by its encryption approach to attribute it to a known family **Do not use** for production data recovery operations without first verifying the decryption method on test copies of encrypted files. ## Prerequisites - Ghidra or IDA Pro for reverse engineering the ransomware binary - Python 3.8+ with `pycryptodome` library for testing encryption/decryption routines - Sample encrypted files and their corresponding plaintext originals (known-plaintext pairs) - Access to the ransomware binary (unpacked if applicable) - Familiarity with symmetric (AES, ChaCha20) and asymmetric (RSA) cryptographic algorithms - NoMoreRansom.org database for checking existing free decryptors ## Workflow ### Step 1: Identify the Encryption Algorithm Determine which cryptographic algorithm the ransomware uses: ```python # Check for Windows Crypto API usage in imports import pefile pe = pefile.PE("ransomware.exe") crypto_apis = { "CryptAcquireContextA": "Windows CryptoAPI",...