From 93d5f2479c5f37094bfa5df957c59fce77276088 Mon Sep 17 00:00:00 2001
From: neptunia <kevinshen100@gmail.com>
Date: Sat, 4 Mar 2017 17:52:26 -0500
Subject: [PATCH] RSA1 with autogen, someone please test if the autogen works
 if possible

---
 RSA1/description.md |  1 +
 RSA1/grader.py      | 46 +++++++++++++++++++++++++++++++++++++++++++++
 RSA1/problem.yml    |  4 ++++
 3 files changed, 51 insertions(+)
 create mode 100644 RSA1/description.md
 create mode 100644 RSA1/grader.py
 create mode 100644 RSA1/problem.yml

diff --git a/RSA1/description.md b/RSA1/description.md
new file mode 100644
index 0000000..d44c07b
--- /dev/null
+++ b/RSA1/description.md
@@ -0,0 +1 @@
+I found somebody's notes on their private RSA! Help me crack [this](${ciphertext_txt}).
\ No newline at end of file
diff --git a/RSA1/grader.py b/RSA1/grader.py
new file mode 100644
index 0000000..e03de4a
--- /dev/null
+++ b/RSA1/grader.py
@@ -0,0 +1,46 @@
+from cStringIO import StringIO
+
+flag = "wh3n_y0u_h4ve_p&q_RSA_iz_ez"
+
+def modx(base,exp,mod):
+    r = 1;
+    while (exp > 0):
+        if (exp % 2 == 1):
+            r = (r * base) % mod
+        base = (base * base) % mod
+        exp = exp/2
+    return r
+
+def probprime(s):
+    while (modx(2,s-1,s) != 1  or  modx(3,s-1,s) != 1  or modx(5,s-1,s) != 1 or modx(7,s-1,s) != 1):
+        s += 1
+    return(s)
+
+def get_problem(random):
+    # add Probable Prime function later
+    p = probprime(random.randint(10**39,9*10**39))
+    q = probprime(random.randint(10**39,9*10**39))
+    e = 3
+    salt = "".join([random.choice("0123456789abcdef") for i in range(8)])
+    return (p, q, e, salt)
+
+def generate_ciphertext(random):
+    p, q, e, salt = get_problem(random)
+    encoded = int(("easyctf{%s_%s}" % (flag, salt)).encode('hex'),16)
+    ciphertext =  'p: '+str(p)+'\n'
+    ciphertext += 'q: '+str(q)+'\n'
+    ciphertext += 'e: '+str(e)+'\n'
+    ciphertext += 'c: '+str(pow(encoded, e, p*q))+'\n'
+
+    return StringIO(ciphertext)
+
+def generate(random):
+    return dict(files={
+        "ciphertext_rsa1.txt": generate_ciphertext
+    })
+
+def grade(random, key):
+    n, salt = get_problem(random)
+    if key.find("%s_%s" % (flag, salt)) >= 0:
+        return True, "Correct!"
+    return False, "Nope."
diff --git a/RSA1/problem.yml b/RSA1/problem.yml
new file mode 100644
index 0000000..e46b8d2
--- /dev/null
+++ b/RSA1/problem.yml
@@ -0,0 +1,4 @@
+title: RSA 1
+value: 25
+author: neptunia
+autogen: true
\ No newline at end of file