All WriteUps for this CTF here: https://github.com/ipv6-feet-under/WriteUps-S.H.E.L.L.CTF21
Easy-RSA
We are given some parameters of the RSA:
n = 1763350599372172240188600248087473321738860115540927328389207609428163138985769311 e = 65537 c = 334752481114211949024977428768859353103048624289808755223333038405651136629435
Just by using the awesome RsaCtfTool (https://github.com/sourcekris/RsaCtfTool or https://github.com/Headorteil/RsaCtfTool) we get the flag:
┌──(kali㉿kali)-[~/Desktop/RsaCtfTool/RsaCtfTool] └─$ python3 ./RsaCtfTool.py -n 1763350599372172240188600248087473321738860115540927328389207609428163138985769311 -e 65537 --uncipher 33475248111421194902497742876885935310304862428980875522333303840565113662943528 private argument is not set, the private key will not be displayed, even if recovered. [*] Testing key /tmp/tmpnodtpx0t. [*] Performing smallq attack on /tmp/tmpnodtpx0t. [*] Performing mersenne_primes attack on /tmp/tmpnodtpx0t. 24%|████████████████████████████████ | 12/51 [00:00<00:00, 399457.52it/s] [*] Performing system_primes_gcd attack on /tmp/tmpnodtpx0t. 100%|███████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 7007/7007 [00:00<00:00, 1625075.37it/s] [*] Performing fibonacci_gcd attack on /tmp/tmpnodtpx0t. 100%|████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 9999/9999 [00:00<00:00, 340797.21it/s] [*] Performing factordb attack on /tmp/tmpnodtpx0t. [*] Attack success with factordb method ! Results for /tmp/tmpnodtpx0t: Unciphered data : HEX : 0x00000000007368656c6c7b737769746368696e5f746f5f6173796d6d65747269637d INT (big endian) : 3111388068276188662361997958100924356274395167698926770307665056326525 INT (little endian) : 3716857967501616239523840250653395077772235796196542527851123201402003116282347520 STR : b'\x00\x00\x00\x00\x00shell{switchin_to_asymmetric}'
转载于:https://ctftime.org/writeup/28723
更详细的使用:https://blog.csdn.net/qq_40657585/article/details/84874073