From 766a36e790952f23cbea91223b7c609df17bf4ab Mon Sep 17 00:00:00 2001
From: Felix Martin <mail@felixm.de>
Date: Wed, 13 Apr 2022 21:42:42 -0400
Subject: [PATCH] Implement challenge 9 pkcs 7 padding.

---
 src/bytes.rs |  8 ++++++++
 src/main.rs  |  3 +++
 src/set2.rs  | 11 +++++++++++
 3 files changed, 22 insertions(+)
 create mode 100644 src/set2.rs

diff --git a/src/bytes.rs b/src/bytes.rs
index 7ef71f1..84d7523 100644
--- a/src/bytes.rs
+++ b/src/bytes.rs
@@ -67,6 +67,14 @@ impl Bytes {
         r
     }
 
+    pub fn pad_pkcs7(&mut self, block_size: usize) -> () {
+        let Bytes(v) = self;
+        let padding_value = (block_size - v.len() % block_size) as u8;
+        for _ in 0..padding_value {
+            v.push(padding_value);
+        }
+    }
+
     pub fn xor(Bytes(a): &Bytes, Bytes(b): &Bytes) -> Bytes {
         Bytes(
             Iterator::zip(a.iter(), b.iter())
diff --git a/src/main.rs b/src/main.rs
index 123ae2b..bd2f177 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,6 +1,7 @@
 mod bytes;
 mod bytes_base64;
 mod set1;
+mod set2;
 
 fn main() {
     set1::challenge1();
@@ -11,4 +12,6 @@ fn main() {
     set1::challenge6();
     set1::challenge7();
     set1::challenge8();
+    set2::challenge9();
+    set2::challenge10();
 }
diff --git a/src/set2.rs b/src/set2.rs
new file mode 100644
index 0000000..26c62f9
--- /dev/null
+++ b/src/set2.rs
@@ -0,0 +1,11 @@
+use crate::bytes::Bytes;
+
+pub fn challenge9() {
+    let mut bytes = Bytes::from_utf8("YELLOW SUBMARINE");
+    bytes.pad_pkcs7(20);
+    println!("[okay] Challenge 9: {:?}", bytes.to_utf8());
+}
+
+pub fn challenge10() {
+    println!("[TBD] Challenge 10: TBD");
+}