Pretty Ridiculous=================50 points---------
The chall gave as ciphertext an array of integers and the values (n, e) = (627585038806247, 65537).This is clearly a public key of RSA and it is noted that the module n is particularly short, therefore it can most likely be factored in a short time:```python#!/usr/bin/python3import math
def prime_factors(n):    i = 2    factors = []    while i * i <= n:        if n % i:            i += 1        else:            n //= i            factors.append(i)    if n > 1:        factors.append(n)    return factors
if __name__ == "__main__":    n = 627585038806247    e = 65537    p, q = prime_factors(n)    print(p, q)```So with the factors p and q it is possible to calculate phi and therefore d:```python#!/usr/bin/python3import math
def egcd(a, b):    if a == 0:        return (b, 0, 1)    else:        g, y, x = egcd(b % a, a)        return (g, x - (b // a) * y, y)
def modinv(a, m):    g, x, y = egcd(a, m)    if g != 1:        raise Exception('modular inverse does not exist')    else:        return x % m
if __name__ == "__main__":    p = 13458281    q = 46631887    ct = 145213650433152
    e = 65537     phi = (p - 1) * (q - 1)
    d = modinv(e, phi)
    print(d)```Finally, only a simple equation remains to be calculated:m = c ** d% n
```python#!/usr/bin/python3import math
def rsadecrypt(x, d, n):    ch = pow(x, d, n)    return ch
if __name__ == "__main__":    d = 119987789848673    n = 627585038806247    ct = [145213650433152, 4562349440334, 24272724667960, 598242834066721, 89584939111364, 426756492371444, 511701778613016, 551732685650248, 296367799892003, 63113462897284, 198510931603899, 321201931522255, 401044612595398, 542697603423052, 213898535689643, 275839755798105, 185841409622217, 551732685650248, 121188708737752, 401044612595398, 512808963720303, 275839755798105, 198510931603899, 275839755798105, 401044612595398, 174484844253615, 551732685650248, 174486913717420, 575163265381617, 213898535689643, 401044612595398, 49103824223436, 551732685650248, 401044612595398, 598242834066721, 202722428784490, 306606077829794, 53801100921263, 401044612595398, 184805755675232, 405971446461049, 296367799892003, 275839755798105, 275839755798105, 401044612595398, 358054299396778, 4562349440334, 320837325468842, 401044612595398, 202722428784490, 551732685650248, 321201931522255, 228350651363859]    for c in ct:        pc = rsadecrypt(c, d, n)        print(chr(pc), end='')    print('\n')```The full script:```python#!/usr/bin/python3import math
#function to find prime factorsdef prime_factors(n):    i = 2    factors = []    while i * i <= n:        if n % i:            i += 1        else:            n //= i            factors.append(i)    if n > 1:        factors.append(n)    return factors
def egcd(a, b):    if a == 0:        return (b, 0, 1)    else:        g, y, x = egcd(b % a, a)        return (g, x - (b // a) * y, y)
#function to calculate inverse moduledef modinv(a, m):    g, x, y = egcd(a, m)    if g != 1:        raise Exception('modular inverse does not exist')    else:        return x % m
#function to calculate plaintextdef rsadecrypt(x, d, n):    ch = pow(x, d, n)    return ch
if __name__ == "__main__":    n = 627585038806247    e = 65537    ct = [145213650433152, 4562349440334, 24272724667960, 598242834066721, 89584939111364, 426756492371444, 511701778613016, 551732685650248, 296367799892003, 63113462897284, 198510931603899, 321201931522255, 401044612595398, 542697603423052, 213898535689643, 275839755798105, 185841409622217, 551732685650248, 121188708737752, 401044612595398, 512808963720303, 275839755798105, 198510931603899, 275839755798105, 401044612595398, 174484844253615, 551732685650248, 174486913717420, 575163265381617, 213898535689643, 401044612595398, 49103824223436, 551732685650248, 401044612595398, 598242834066721, 202722428784490, 306606077829794, 53801100921263, 401044612595398, 184805755675232, 405971446461049, 296367799892003, 275839755798105, 275839755798105, 401044612595398, 358054299396778, 4562349440334, 320837325468842, 401044612595398, 202722428784490, 551732685650248, 321201931522255, 228350651363859]    p, q = prime_factors(n)
    phi = (p - 1) * (q - 1)    d = modinv(e, phi)     for c in ct:        pc = rsadecrypt(c, d, n)        print(chr(pc), end='')    print('')```