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