From 9e8502081cb418ff034cdbc7ef836f5a87088dba Mon Sep 17 00:00:00 2001
From: agatha <agatha@juggalol.com>
Date: Fri, 25 Oct 2024 16:23:41 -0400
Subject: [PATCH] crypto: interpolation

---
 crypto/interpolation/interpolation.zip        | Bin 0 -> 1377 bytes
 crypto/interpolation/interpolation/Dockerfile |  11 +++++++
 crypto/interpolation/interpolation/chall.sage |  31 ++++++++++++++++++
 crypto/interpolation/interpolation/entry.sh   |   6 ++++
 4 files changed, 48 insertions(+)
 create mode 100644 crypto/interpolation/interpolation.zip
 create mode 100644 crypto/interpolation/interpolation/Dockerfile
 create mode 100755 crypto/interpolation/interpolation/chall.sage
 create mode 100644 crypto/interpolation/interpolation/entry.sh

diff --git a/crypto/interpolation/interpolation.zip b/crypto/interpolation/interpolation.zip
new file mode 100644
index 0000000000000000000000000000000000000000..7ba3e64aad51724bc892bab2e531a2c0db7cf281
GIT binary patch
literal 1377
zcmWIWW@h1H00F@j;gMhll;C5KVaUuYNi8bK&q*xF%+J#g4dG;9zT_^Mein#JE4UdL
zSza(RFo1~wpgAHyog83uj&6E6dmfN?9Ec?_%yG$2&Q2{#%gjlIn+P%$%|zF}i(E|x
z60PsQi`Wa@vs|yjv5Sj&;Wk5Y6+y#i1&vmjlPA2mJG-@{{D;N!$8Ricn<n?ZTVnoF
z$ZYMGTa_(8Ivb?3xr;s+@Rc5z;3IInzUuwl>ABX)=~H<Y%chE|bQ*oTnV+tjaKL`L
z(cHC(b5j>o|DUnJn6cG#UN*<mbhpzoVe6d(yXM@Hc=|}zKyXje76m4~z^t6*`~5E;
z6^yk<_3t*zt(w_Dzm@>87>0jS^Gb>;^@=m_`8GH#<bwaHGne(xJ$R&b{=^y2&<&5g
zPCgG}XnOSL$q}Jef#(dd^5-82gxhOR&EinDJ7BM|Burg*zs6RbtscuYwr;U7HB?>7
zp)zUh1F46va+a=}KXLx-Rq=CX%v&{o&cqp$7qcg=V(vZX{gjCT)#=CX9pj(H$iPs{
zge|I)GZJ%h^okSH@kdplW8Q58fjyr^v%fkmGs<Pp43PF{JkapknZH$^Rf~g7bgjxZ
z5zPrEtIST^-#q0`i+WLddRf}f#ErXH_OIF!%X(Gm^4|wFEq<-%UcCB$Svk4B<jn!z
zjLK^gS5H|S(`i2wK9fOo!A-*j#Xr9N5S3dnQ7-iC(U4%p2P#U{qVui%rYKi^k6AN4
zdh4I>JN{Ja&ENidy7(pUnu9kQP55rT>R|6(_H4Vk`S$tm5;<p|k3Q(vQdj<Led*q?
zXG?NV^QWYqVX+oU35mbT^@eXt?;k1GHou81+nvfRuI)N1u=7M>vHp#Jb4}hYu=up`
zf<w*^j`F1q$0~PabI08j`)S4Q96e*svjTOmV^TsEAOFTE|88D<va!qcq|om_=kii|
z*SbG(IwSpAbCt@5vcHnN-#nH*KYG?Eh<D4^S>kr>ZPkHXW<RFnv}MNp;t#r5w!>v!
z?a3CG-%qk;DV|-={j}z@_u02svz3;Xe==98-+U*>%lyKpg%QEOjxzHcT{h?S<kguK
z-ws>fb_$A2dBnTs#r=9?6UOvITPywd#vPpy70(#p&B!Fjj4Ojn0Fx^S2r#^L1kvc(
zofVSZ(K05)Ok9~AVkR&_F)V5Hz%Uaz>l0@>YSuzF-2!L{s*4dBjX1MW(>}uNw~e1M
a%tp=$xJ+kd1BD_B5as~&-v^eB3=9C-n()d1

literal 0
HcmV?d00001

diff --git a/crypto/interpolation/interpolation/Dockerfile b/crypto/interpolation/interpolation/Dockerfile
new file mode 100644
index 0000000..b6c2536
--- /dev/null
+++ b/crypto/interpolation/interpolation/Dockerfile
@@ -0,0 +1,11 @@
+FROM sagemath/sagemath:latest
+
+RUN sudo apt update -y && sudo apt install -y socat
+
+COPY --chown=sage . .
+
+RUN chmod 755 entry.sh chall.sage
+
+EXPOSE ${LISTEN_PORT}
+
+ENTRYPOINT ["/home/sage/entry.sh"]
\ No newline at end of file
diff --git a/crypto/interpolation/interpolation/chall.sage b/crypto/interpolation/interpolation/chall.sage
new file mode 100755
index 0000000..d47069e
--- /dev/null
+++ b/crypto/interpolation/interpolation/chall.sage
@@ -0,0 +1,31 @@
+#!/usr/bin/sage
+import hashlib
+import re
+
+with open("flag.txt", "rb") as f:
+    FLAG = f.read()
+    assert re.match(rb"Hero{[0-9a-zA-Z_]{90}}", FLAG)
+
+F = FiniteField(2**256 - 189)
+R = PolynomialRing(F, "x")
+H = lambda n: int(hashlib.sha256(n).hexdigest(), 16)
+C = lambda x: [H(x[i : i + 4]) for i in range(0, len(FLAG), 4)]
+
+f = R(C(FLAG))
+
+points = []
+for _ in range(f.degree()):
+    r = F.random_element()
+    points.append([r, f(r)])
+print(points)
+
+flag = input(">").encode().ljust(len(FLAG))
+
+g = R(C(flag))
+
+for p in points:
+    if g(p[0]) != p[1]:
+        print("Wrong flag!")
+        break
+else:
+    print("Congrats!")
diff --git a/crypto/interpolation/interpolation/entry.sh b/crypto/interpolation/interpolation/entry.sh
new file mode 100644
index 0000000..15caf60
--- /dev/null
+++ b/crypto/interpolation/interpolation/entry.sh
@@ -0,0 +1,6 @@
+#! /bin/sh
+
+while :
+do
+    socat TCP-LISTEN:${LISTEN_PORT},forever,reuseaddr,fork EXEC:'/home/sage/chall.sage'
+done