Rating: 1.0

# RSA-1
## Description

I have a lot of big numbers. Here, have a few!

big_numbers.txt:

Ever used RSA Encryption?

cyphertext = 10400286653072418349777706076384847966640064725838262071
n = 23519325203263800569051788832344215043304346715918641803
e = 71


Here we can see it's common and easy RSA challenge where n,e,c are given and we have to decrypt the flag.

Here We used RsaCtfTool and got the flag.

[email protected]:~/RsaCtfTool# python3 RsaCtfTool.py -n 23519325203263800569051788832344215043304346715918641803 -e 71 \--uncipher 10400286653072418349777706076384847966640064725838262071

private argument is not set, the private key will not be displayed, even if recovered.

[*] Testing key /tmp/tmps9_oxcq2.

[*] Performing mersenne_primes attack on /tmp/tmps9_oxcq2.

24%|███████████████████████████████████ | 12/51 [00:00<00:00, 262144.00it/s]

[*] Performing smallq attack on /tmp/tmps9_oxcq2.

[*] Performing pastctfprimes attack on /tmp/tmps9_oxcq2.

100%|███████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 113/113 [00:00<00:00, 973216.33it/s]

[*] Performing fibonacci_gcd attack on /tmp/tmps9_oxcq2.

100%|█████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 9999/9999 [00:00<00:00, 264363.22it/s]

[*] Performing system_primes_gcd attack on /tmp/tmps9_oxcq2.

100%|████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 7007/7007 [00:00<00:00, 1218469.66it/s]

[*] Performing factordb attack on /tmp/tmps9_oxcq2.

[*] Attack success with factordb method !

Results for /tmp/tmps9_oxcq2:

Unciphered data :

HEX : 0x6473637b7430305f6d7563685f6d3474685f383839387d

INT (big endian) : 9621269132073872010525638902903988134500010392708266109

INT (little endian) : 11993657127041496499871362328745731192598296696556057444

utf-8 : dsc{t00_much_m4th_8898}

STR : b'dsc{t00_much_m4th_8898}'


## Tools
RsaCtfTool :- https://github.com/Ganapati/RsaCtfTool.git

Original writeup (https://github.com/S-H-E-L-L/DeconstructCTF/blob/main/crypto/RSA-1.md).