Question 1

How do I encrypt an ELF binary with ELFcrypt?

Accepted Answer

Compile your program with the CRYPTED macro on target functions, then run ./ELFcrypt on the binary with a passphrase. For full-binary encryption, use ELFcrypt2 and concatenate the stub with the encrypted output, as shown in the README with /bin/ls.

Question 2

Is ELFcrypt secure enough for protecting proprietary code?

Accepted Answer

It deters casual static analysis but is not secure for high-stakes applications due to RC4's vulnerabilities and lack of runtime protection. Use it for obfuscation, not for strong cryptographic security.

Question 3

ELFcrypt vs UPX: which is better for binary obfuscation?

Accepted Answer

ELFcrypt focuses on encryption with passphrase protection, while UPX is a packer for compression and basic obfuscation without encryption. Choose ELFcrypt if you need encryption, but UPX is more widely supported for size reduction.

Question 4

Can ELFcrypt work on ARM or other architectures?

Accepted Answer

It targets ELF binaries, so in theory it could work on ARM ELF files, but the tool is designed and tested for x86-64 Linux. Portability may require modifications to handle different ELF variants.

Question 5

What happens if I lose the passphrase for an encrypted binary?

Accepted Answer

The binary becomes unrecoverable because decryption requires the correct passphrase. There is no backdoor or recovery mechanism, so store passphrases securely or use environment variables for automation.

Question 6

Does ELFcrypt protect against debugging or tampering during execution?

Accepted Answer

No, it only encrypts code at rest. Once decrypted in memory, the code is exposed and vulnerable to debugging, memory dumps, or modification, as admitted in the README.

Question 7

How to use environment variables instead of typing passphrases?

Accepted Answer

Set the ELFCRYPT environment variable to the passphrase before running the encrypted binary. For example, 'ELFCRYPT="mypass" ./crypted' will decrypt without interactive prompts, as shown in the quick start.

ELFCrypt

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