RsaCtfTool – Data decrypter tool


RsaCtfTool decrypts data that uses weak RSA keys. It also recovers private keys using a variety of automated attacks.


How to get this tool

To use this tool, please use a method listed below.

In a Linux (Debian OS), run the following command(s).

Clone the repo

git clone && cd RsaCtfTool/


Download directly from the following link:


How to execute

Uncipher file :

./ --publickey ./ --uncipher ./ciphered\_file


Print private key :

./ --publickey ./ --private


Attempt to break multiple public keys with common factor attacks or individually - use quotes around wildcards to stop bash expansion

./ --publickey "*.pub" --private


Generate a public key :

./ --createpub --n 7828374823761928712873129873981723...12837182
  --e 65537


Dump the parameters from a key:

./ --dumpkey --key ./


Factor with ECM when you know the approximate length in digits of a prime:

./ --publickey --ecmdigits 25 --verbose --private





Next steps:


This article was contributed by Gavin Dennis from Jamaica. Gavin is a member of the Caribbean CSPA.

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