It's RSA, with a suspiciously short modulus.  Factorizing it is
trivial with Wolfram Alpha.  Knowing `p` and `q` decrypting the cipher
text is trivial:

    n = 126390312099294739294606157407778835887
    e = 65537
    c = 13612260682947644362892911986815626931

    p = 9336949138571181619
    q = 13536574980062068373
    d = 122116681453826726664714315157880092841
    m = 505669976011892616877716395432178557
    hex(m) = 616374667b31306d696e757465737d
    hexdecode(hex(m)) = "actf{10minutes}"