Fixing up hash slides with notes and edits pre lecture (#889)

* Fixing up hash slides with notes and edits pre lecture

* reverting lock

* reverting lock

---------

Co-authored-by: drskalman <35698397+drskalman@users.noreply.github.com>

syllabus/1-Cryptography/3-Hashes-slides.md

@@ -18,19 +18,20 @@ We often want a succinct representation of some data<br />with the expectation t
 
 ## Hash Function Properties
 
-<pba-flex center>
 
-<section>
-    <p class="fragment">Accept unbounded size input</p>
-    <p class="fragment">Map to a bounded output</p>
-    <p class="fragment">Be fast to compute</p>
-    <p class="fragment">Be computable strictly one-way<br />(difficult to find a pre-image for a hash)</p>
-    <p class="fragment">Resist pre-image attacks<br />(attacker controls one input)</p>
-    <p class="fragment">Second pre-image resistance: Given an input and output<br />(resisting second pre-image attacks).</p>
-    <p class="fragment">Resist collisions<br />(attacker controls both inputs)</p>
-</section>
+- Accept unbounded size input <!-- .element: class="fragment" data-fragment-index="0" -->
+- Map to a bounded output <!-- .element: class="fragment" data-fragment-index="1" -->
+- Be fast to compute <!-- .element: class="fragment" data-fragment-index="2" -->
+- Be computable strictly one-way<br />(difficult to find a pre-image for a hash) <!-- .element: class="fragment" data-fragment-index="3" -->
+- Resist pre-image attacks<br />(attacker controls one input) <!-- .element: class="fragment" data-fragment-index="4" -->
+- Second pre-image resistance: Given an input and output<br />(resisting second pre-image attacks). <!-- .element: class="fragment" data-fragment-index="5" -->
+- Resist collisions<br />(attacker controls both inputs) <!-- .element: class="fragment" data-fragment-index="6" -->
 
-</pba-flex>
+Notes:
+ 1. one way meaning for a given output difficult to get the input
+ 1. attacker has the value 5 and from that can find a preimage that hashes to 5 (5 just an example value)
+ 1. attacker has input and output and cant find a another input which maps to the output
+ 1. More generally the attacker has the entire input space and cant find two inputs which hash to the same value
 
 ---
 
@@ -59,7 +60,7 @@ hash('hello') =
 **Large input (1.2 MB):**
 
 ```text
-hash(Harry_Potter_series_as_string) =
+hash(Harry_Potter_series_as_string) u
  0xc4d194054f03dc7155ccb080f1e6d8519d9d6a83e916960de973c93231aca8f4
 ```
 
@@ -99,11 +100,10 @@ See the Jupyter notebook and/or HackMD cheat sheet for this lesson.
 
 ## Speed
 
-Some hash functions are designed to be slow.
-
-These have applications like password hashing, which would slow down brute-force attackers.
-
-For our purposes, we generally want them to be fast.
+- Some hash functions are designed to be slow. <!-- .element: class="fragment" data-fragment-index="0" -->
+- Does anyone know why someone would want a hash function to be slow? <!-- .element: class="fragment" data-fragment-index="1" -->
+- These have applications like password hashing, which would slow down brute-force attackers. <!-- .element: class="fragment" data-fragment-index="2" --> 
+- For our purposes, we generally want them to be fast. <!-- .element: class="fragment" data-fragment-index="3" -->
 
 ---
 
@@ -236,8 +236,8 @@ single hash collision often results in the hash function being considered unsafe
 
 > With 23 people, there is a 6% chance that someone will be born on a specific date, but a 50% chance that two share a birthday.
 
-- Must compare each output with every other, not with a single one.<br />
-- Number of possible "hits" increases exponentially for more attempts, reducing the expected success to the square-root of what a specific target would be.
+- Must compare each birthday with every other, not with a single one.<br /> <!-- .element: class="fragment" data-fragment-index="0" -->
+- Number of possible "hits" increases exponentially for more attempts, reducing the expected success to the square-root of what a specific target would be. <!-- .element: class="fragment" data-fragment-index="1" -->
 
 </pba-col>
 <pba-col>
@@ -269,11 +269,14 @@ e.g., a 256 bit hash output yields 2^128 security
 
 It should be difficult for someone to partially (for a substring of the hash output) find a collision or "second" pre-image.
 
-<section>
-    <p class="fragment">Bitcoin PoW is a partial pre-image attack.</p>
-    <p class="fragment">Prefix/suffix pre-image attack resistance reduces opportunity for UI attacks for address spoofing.</p>
-    <p class="fragment">Prefix collision resistance important to rationalize costs for some cryptographic data structures.</p>
-</section>
+- Bitcoin PoW is a partial pre-image attack. <!-- .element: class="fragment" data-fragment-index="0" -->
+- Can anyone explain how? <!-- .element: class="fragment" data-fragment-index="1" --> 
+- Prefix/suffix pre-image attack resistance reduces opportunity for UI attacks for address spoofing.<!-- .element: class="fragment" data-fragment-index="2" -->
+- Prefix collision resistance important to rationalize costs for some cryptographic data structures.<!-- .element: class="fragment" data-fragment-index="3" -->
+
+Notes:
+This is a technique used to trick users into thinking they are interacting with a trusted entity (like a account or piece of data) when they are actually interacting with a malicious actor. This can be done by creating a fraudulent address that looks similar to a legitimate one.
+example AEVXZ AEVYZ 
 
 ---
 
@@ -307,9 +310,8 @@ Let's see which cryptographic properties apply to hashes.
 
 ## Confidentiality
 
-Sending or publically posting a hash of some data $D$ keeps $D$ confidential, as only those who already knew $D$ recognize $H(D)$ as representing $D$.
-
-Both cryptographic and non-cryptographic hashes work for this. _only if the input space is large enough_.
+- Sending or publicly posting a hash of some data $D$ keeps $D$ confidential, as only those who already knew $D$ recognize $H(D)$ as representing $D$.
+- Both cryptographic and non-cryptographic hashes work for this, _only if the input space is large enough_.
 
 ---v
 
@@ -327,6 +329,9 @@ The other player doesn't need to undo the hash function to know what you played!
 
 Notes:
 
+Question:
+How can we fix this issue?
+
 The data space has to be _sufficiently large_.
 Adding some randomness to input of the hash fixes this. Add x bits of randomness to make it x bits of security on that hash.
 
@@ -352,6 +357,8 @@ However, if used in another cryptographic primitive that _does_ provide non-repu
 
 Notes:
 
+- The hash alone doesnt give one the ability to authenticate or identify the originator of the data because anyone with access to the data can produce the same hash. 
+
 This is key in digital signatures. However, it's important to realize that if $D$ is kept secret, $H(D)$ is basically meaningless.
 
 ---
@@ -374,7 +381,9 @@ In [Bittorrent](https://en.wikipedia.org/wiki/BitTorrent), each file chunk is ha
 
 Notes:
 
-The hash of the large file can also serve as a signal to the protocol that transmission is complete.
+- Content addressed file is when a file is identified based on the content of the file. 
+
+- The hash of the large file can also serve as a signal to the protocol that transmission is complete.
 
 ---
 
@@ -408,11 +417,12 @@ Hash of pub key:
 
 It is often useful to commit to some information<br /> without storing or revealing it:
 
-- A prediction market would want to reveal predictions only after the confirming/refuting event occurred.
-- Users of a system may want to discuss proposals without storing the proposal on the system.
-
-However, participants should not be able to modify their predictions or proposals.
+- A prediction market would want to reveal predictions only after the confirming/refuting event occurred.<!-- .element: class="fragment" data-fragment-index="0" -->
+- Users of a system may want to discuss proposals without storing the proposal on the system.<!-- .element: class="fragment" data-fragment-index="1" -->
+- However, participants should not be able to modify their predictions or proposals.<!-- .element: class="fragment" data-fragment-index="2" -->
 
+Notes:
+What is an example of an application would use an application like this?
 ---
 
 ## Commit-Reveal