Up to DescribeDigitalSignatures in crypto

This commit is contained in:
Grant Sanderson 2017-06-21 22:55:10 -07:00
parent ef9fbd7aa9
commit 05db6174e9
4 changed files with 610 additions and 66 deletions

629
crypto.py
View file

@ -33,6 +33,11 @@ from mobject.tex_mobject import *
BITCOIN_COLOR = "#f7931a"
def get_cursive_name(name):
result = TextMobject("\\normalfont\\calligra %s"%name)
result.set_stroke(width = 0.5)
return result
##################
class AskQuestion(Scene):
@ -163,6 +168,9 @@ class LedgerScene(PiCreatureScene):
PiCreatureScene.setup(self)
self.remove(self.pi_creatures)
def add_ledger_and_network(self):
self.add(self.get_ledger(), self.get_network())
def get_ledger(self):
title = TextMobject("Ledger")
rect = Rectangle(
@ -206,15 +214,13 @@ class LedgerScene(PiCreatureScene):
amount_str += " " + self.denomination
line = TextMobject(
from_name.capitalize(),
"pays" if from_name.lower() is not "you" else "pay",
"pays" if from_name.lower() != "you" else "pay",
to_name.capitalize(),
amount_str
)
for name in from_name, to_name:
if hasattr(self, name.lower()):
creature = getattr(self, name.lower())
color = creature.get_color()
line.highlight_by_tex(name.capitalize(), color)
color = self.get_color_from_name(name)
line.highlight_by_tex(name.capitalize(), color)
if self.denomination == "USD":
line.highlight_by_tex(amount_str, GREEN_D)
elif self.denomination == "BTC":
@ -222,11 +228,20 @@ class LedgerScene(PiCreatureScene):
return self.add_line_to_ledger(line)
def get_color_from_name(self, name):
if hasattr(self, name.lower()):
creature = getattr(self, name.lower())
color = creature.get_color()
if np.mean(color.get_rgb()) < 0.5:
color = average_color(color, color, WHITE)
return color
return WHITE
def animate_payment_addition(self, *args, **kwargs):
line = self.add_payment_line_to_ledger(*args, **kwargs)
self.play(LaggedStart(
FadeIn,
VGroup(*line.family_members_with_points()),
VGroup(*it.chain(*line)),
run_time = 1
))
@ -241,24 +256,24 @@ class LedgerScene(PiCreatureScene):
for pi1, pi2 in it.combinations(creatures, 2)
])
labels = VGroup(*[pi.label for pi in creatures])
return VGroup(creatures, labels, lines)
self.network = VGroup(creatures, labels, lines)
return self.network
def create_pi_creatures(self):
creatures = VGroup(*[
PiCreature(color = color, height = 1).shift(2*vect)
for color, vect in zip(
[BLUE_B, MAROON_D, GREY_BROWN, BLUE_E],
[BLUE_C, MAROON_D, GREY_BROWN, BLUE_E],
[UP+LEFT, UP+RIGHT, DOWN+LEFT, DOWN+RIGHT],
)
])
creatures.to_edge(RIGHT)
names = ["alice", "bob", "charlie", "you"]
names = self.get_names()
for name, creature in zip(names, creatures):
setattr(self, name, creature)
label = TextMobject(name.capitalize())
label.scale(0.5)
label.next_to(creature, DOWN)
label.scale(0.75)
label.next_to(creature, DOWN, SMALL_BUFF)
creature.label = label
if (creature.get_center() - creatures.get_center())[0] > 0:
creature.flip()
@ -266,6 +281,8 @@ class LedgerScene(PiCreatureScene):
return creatures
def get_names(self):
return ["alice", "bob", "charlie", "you"]
class LayOutPlan(LedgerScene):
def construct(self):
@ -404,25 +421,575 @@ class UnderlyingSystemVsUserFacing(Scene):
self.play(DrawBorderThenFill(phone))
self.dither(2)
class CryptoPrefix(Scene):
def construct(self):
cryptocurrency = TextMobject(
"Crypto", "currency",
arg_separator = ""
)
crypto = cryptocurrency.get_part_by_tex("Crypto")
brace = Brace(crypto, UP)
explanation = TextMobject(
"Built using the math \\\\ from cryptography"
)
explanation.next_to(brace, UP)
self.add(cryptocurrency)
self.play(
crypto.highlight, YELLOW,
GrowFromCenter(brace)
)
self.play(Write(explanation))
self.dither(3)
class IntroduceLedgerSystem(LedgerScene):
CONFIG = {
"payments" : [
("Alice", "Bob", 20),
("Bob", "Charlie", 40),
("Charlie", "You", 30),
("You", "Alice", 10),
]
}
def construct(self):
self.add(self.get_network())
self.exchange_money()
self.add_ledger()
self.tally_it_all_up()
def exchange_money(self):
for from_name, to_name, num in self.payments:
from_pi = getattr(self, from_name.lower())
to_pi = getattr(self, to_name.lower())
cash = TexMobject("\\$"*(num/10)).highlight(GREEN)
cash.scale_to_fit_height(0.5)
cash.move_to(from_pi)
self.play(
cash.move_to, to_pi,
to_pi.change_mode, "hooray"
)
self.play(FadeOut(cash))
self.dither()
def add_ledger(self):
ledger = self.get_ledger()
self.play(
Write(ledger),
*[
ApplyMethod(pi.change, "pondering", ledger)
for pi in self.pi_creatures
]
)
for payment in self.payments:
self.animate_payment_addition(*payment)
self.dither(3)
def tally_it_all_up(self):
accounts = dict()
names = "alice", "bob", "charlie", "you"
for name in names:
accounts[name] = 0
for from_name, to_name, amount in self.payments:
accounts[from_name.lower()] -= amount
accounts[to_name.lower()] += amount
results = VGroup()
debtors = VGroup()
creditors = VGroup()
for name in names:
amount = accounts[name]
creature = getattr(self, name)
creature.cash = TexMobject("\\$"*abs(amount/10))
creature.cash.next_to(creature, UP+LEFT, SMALL_BUFF)
creature.cash.highlight(GREEN)
if amount < 0:
verb = "Owes"
debtors.add(creature)
else:
verb = "Gets"
creditors.add(creature)
if name == "you":
verb = verb[:-1]
result = TextMobject(
verb, "\\$%d"%abs(amount)
)
result.highlight_by_tex("Owe", RED)
result.highlight_by_tex("Get", GREEN)
result.add_background_rectangle()
result.scale(0.7)
result.next_to(creature.label, DOWN)
results.add(result)
brace = Brace(VGroup(*self.ledger.content[1:]), RIGHT)
tally_up = brace.get_text("Tally up")
tally_up.add_background_rectangle()
self.play(
GrowFromCenter(brace),
FadeIn(tally_up)
)
self.play(
LaggedStart(FadeIn, results),
*[
ApplyMethod(pi.change, "happy")
for pi in creditors
] + [
ApplyMethod(pi.change, "plain")
for pi in debtors
]
)
self.dither()
debtor_cash, creditor_cash = [
VGroup(*it.chain(*[pi.cash for pi in group]))
for group in debtors, creditors
]
self.play(FadeIn(debtor_cash))
self.play(
debtor_cash.arrange_submobjects, RIGHT, SMALL_BUFF,
debtor_cash.move_to, self.pi_creatures,
)
self.dither()
self.play(ReplacementTransform(
debtor_cash, creditor_cash
))
self.dither(2)
class InitialProtocol(Scene):
def construct(self):
title = TextMobject("Protocol")
title.scale(1.5)
title.to_edge(UP)
h_line = Line(LEFT, RIGHT).scale(4)
h_line.next_to(title, DOWN)
items = VGroup(*map(TextMobject, [
"$\\cdot$ Anyone can add lines to the Ledger",
"$\\cdot$ Settle up with real money each month"
]))
items.arrange_submobjects(
DOWN,
buff = MED_LARGE_BUFF,
aligned_edge = LEFT
)
items.next_to(h_line, DOWN, MED_LARGE_BUFF)
self.add(title, h_line)
for item in items:
self.dither()
self.play(LaggedStart(FadeIn, item))
self.dither(2)
self.title = title
self.items = items
class AddFraudulentLine(LedgerScene):
def construct(self):
self.add_ledger_and_network()
self.bob_adds_lines()
self.alice_reacts()
def bob_adds_lines(self):
line = self.add_payment_line_to_ledger("Alice", "Bob", 100)
line.save_state()
line.scale(0.001)
line.move_to(self.bob)
self.play(self.bob.change, "conniving")
self.play(line.restore)
self.dither()
def alice_reacts(self):
bubble = SpeechBubble(
height = 1.5, width = 2, direction = LEFT,
)
bubble.next_to(self.alice, UP+RIGHT, buff = 0)
bubble.write("Hey!")
self.play(
Animation(self.bob.pupils),
self.alice.change, "angry",
FadeIn(bubble),
Write(bubble.content, run_time = 1)
)
self.dither(3)
self.play(
FadeOut(bubble),
FadeOut(bubble.content),
self.alice.change_mode, "pondering"
)
class AnnounceDigitalSignatures(TeacherStudentsScene):
def construct(self):
words = TextMobject("Digital \\\\ signatures!")
words.scale(1.5)
self.force_skipping()
self.teacher_says(
words,
target_mode = "hooray",
)
self.revert_to_original_skipping_status()
self.change_student_modes(*["hooray"]*3)
self.dither(2)
class IntroduceSignatures(LedgerScene):
CONFIG = {
"payments" : [
("Alice", "Bob", 100),
("Charlie", "You", 20),
("Bob", "You", 30),
],
}
def construct(self):
self.add_ledger_and_network()
self.add_transactions()
self.add_signatures()
def add_transactions(self):
transactions = VGroup(*[
self.add_payment_line_to_ledger(*payment)
for payment in self.payments
])
self.play(LaggedStart(FadeIn, transactions))
self.dither()
def add_signatures(self):
signatures = VGroup(*[
get_cursive_name(payments[0].capitalize())
for payments in self.payments
])
for signature, transaction in zip(signatures, self.ledger.content[1:]):
signature.next_to(transaction, RIGHT)
signature.highlight(transaction[0].get_color())
self.play(Write(signature, run_time = 2))
transaction.add(signature)
self.dither(2)
rect = SurroundingRectangle(self.ledger.content[1])
self.play(ShowCreation(rect))
self.play(FadeOut(rect))
self.dither()
self.play(Indicate(signatures[0]))
self.dither()
class AskHowDigitalSignaturesArePossible(TeacherStudentsScene):
def construct(self):
signature = get_cursive_name("Alice")
signature.scale(1.5)
signature.highlight(BLUE_C)
signature.to_corner(UP+LEFT)
signature_copy = signature.copy()
signature_copy.shift(3*RIGHT)
bits = TexMobject("01100001")
bits.next_to(signature, DOWN)
bits.shift_onto_screen()
bits_copy = bits.copy()
bits_copy.next_to(signature_copy, DOWN)
self.add(signature)
self.student_says(
"Couldn't you just \\\\ copy the signature?",
target_mode = "confused",
run_time = 1
)
self.change_student_modes("pondering", "confused", "erm")
self.play(LaggedStart(FadeIn, bits, run_time = 1))
self.dither()
self.play(ReplacementTransform(
bits.copy(), bits_copy,
path_arc = np.pi/2
))
self.play(Write(signature_copy))
self.dither(3)
class DescribeDigitalSignatures(LedgerScene):
CONFIG = {
"public_color" : GREEN,
"private_color" : RED,
"signature_color" : BLUE_C,
}
def construct(self):
self.reorganize_pi_creatures()
self.generate_key_pairs()
self.keep_secret_key_secret()
self.show_handwritten_signatures()
self.show_digital_signatures()
self.show_signing_functions()
def reorganize_pi_creatures(self):
self.pi_creatures.remove(self.you)
creature_groups = VGroup(*[
VGroup(pi, pi.label).scale(1.7)
for pi in self.pi_creatures
])
creature_groups.arrange_submobjects(RIGHT, buff = 2)
creature_groups.to_edge(DOWN)
self.add(creature_groups)
for pi in self.pi_creatures:
if pi.is_flipped():
pi.flip()
def generate_key_pairs(self):
title = TextMobject("Private", "key /", "Public", "key")
title.to_edge(UP)
private, public = map(title.get_part_by_tex, ["Private", "Public"])
private.highlight(self.private_color)
public.highlight(self.public_color)
secret = TextMobject("Secret")
secret.move_to(private, RIGHT)
secret.highlight(self.private_color)
names = self.get_names()[:-1]
public_key_strings = [
bin(256+ord(name[0].capitalize()))[3:]
for name in names
]
private_key_strings = [
bin(hash(name))[2:10]
for name in names
]
public_keys, private_keys = [
VGroup(*[
TextMobject(key_name+":"," $%s\\dots$"%key)
for key in keys
])
for key_name, keys in [
("pk", public_key_strings),
("sk", private_key_strings)
]
]
key_pairs = [
VGroup(*pair).arrange_submobjects(DOWN, aligned_edge = LEFT)
for pair in zip(public_keys, private_keys)
]
for key_pair, pi in zip(key_pairs, self.pi_creatures):
key_pair.next_to(pi, UP, MED_LARGE_BUFF)
for key in key_pair:
key.highlight_by_tex("sk", self.private_color)
key.highlight_by_tex("pk", self.public_color)
self.play(Write(title, run_time = 2))
self.play(ReplacementTransform(
VGroup(VGroup(public.copy())),
public_keys
))
self.play(ReplacementTransform(
VGroup(VGroup(private.copy())),
private_keys
))
self.dither()
self.play(private.shift, DOWN)
self.play(FadeIn(secret))
self.play(FadeOut(private))
self.dither()
title.remove(private)
title.add(secret)
self.title = title
self.private_keys = private_keys
self.public_keys = public_keys
def keep_secret_key_secret(self):
keys = self.private_keys
rects = VGroup(*map(SurroundingRectangle, keys))
rects.highlight(self.private_color)
lock = SVGMobject(
file_name = "lock",
height = rects.get_height(),
fill_color = LIGHT_GREY,
fill_opacity = 1,
stroke_width = 0,
)
locks = VGroup(*[
lock.copy().next_to(rect, LEFT, SMALL_BUFF)
for rect in rects
])
self.play(ShowCreation(rects))
self.play(LaggedStart(DrawBorderThenFill, locks))
self.dither()
self.private_key_rects = rects
self.locks = locks
def show_handwritten_signatures(self):
lines = VGroup(*[Line(LEFT, RIGHT) for x in range(5)])
lines.arrange_submobjects(DOWN)
last_line = lines[-1]
last_line.scale(0.7, about_point = last_line.get_left())
signature_line = lines[0].copy()
signature_line.set_stroke(width = 2)
signature_line.next_to(lines, DOWN, LARGE_BUFF)
ex = TexMobject("\\times")
ex.scale(0.7)
ex.next_to(signature_line, UP, SMALL_BUFF, LEFT)
lines.add(ex, signature_line)
rect = SurroundingRectangle(
lines,
color = LIGHT_GREY,
buff = MED_SMALL_BUFF
)
document = VGroup(rect, lines)
documents = VGroup(*[
document.copy()
for x in range(2)
])
documents.arrange_submobjects(RIGHT, buff = MED_LARGE_BUFF)
documents.to_corner(UP+LEFT)
signatures = VGroup()
for document in documents:
signature = get_cursive_name("Alice")
signature.highlight(self.signature_color)
line = document[1][-1]
signature.next_to(line, UP, SMALL_BUFF)
signatures.add(signature)
self.play(
FadeOut(self.title),
LaggedStart(FadeIn, documents, run_time = 1)
)
self.play(Write(signatures))
self.dither()
self.signatures = signatures
self.documents = documents
def show_digital_signatures(self):
rect = SurroundingRectangle(VGroup(
self.public_keys[0],
self.private_key_rects[0],
self.locks[0]
))
digital_signatures = VGroup()
for i, signature in enumerate(self.signatures):
bits = bin(hash(str(i)))[-8:]
digital_signature = TexMobject(bits + "\\dots")
digital_signature.scale(0.7)
digital_signature.highlight(signature.get_color())
digital_signature.move_to(signature, DOWN)
digital_signatures.add(digital_signature)
arrows = VGroup(*[
Arrow(
rect.get_corner(UP), sig.get_bottom(),
tip_length = 0.15,
color = WHITE
)
for sig in digital_signatures
])
words = VGroup(*map(
TextMobject,
["Different messages", "Completely different signatures"]
))
words.arrange_submobjects(DOWN, aligned_edge = LEFT)
words.scale(1.3)
words.next_to(self.documents, RIGHT)
self.play(FadeIn(rect))
self.play(*map(ShowCreation, arrows))
self.play(Transform(self.signatures, digital_signatures))
self.play(*[
ApplyMethod(pi.change, "pondering", digital_signatures)
for pi in self.pi_creatures
])
for word in words:
self.play(FadeIn(word))
self.dither()
self.play(FadeOut(words))
def show_signing_functions(self):
sign = TextMobject(
"Sign(", "Message", ", ", "sk", ") = ", "Signature",
arg_separator = ""
)
sign.to_corner(UP+RIGHT)
verify = TextMobject(
"Verify(", "Message", ", ", "Signature", ", ", "pk", ") = ", "T/F",
arg_separator = ""
)
for mob in sign, verify:
mob.highlight_by_tex("sk", self.private_color)
mob.highlight_by_tex("pk", self.public_color)
mob.highlight_by_tex(
"Signature", self.signature_color,
)
for name in "Message", "sk", "Signature", "pk":
part = mob.get_part_by_tex(name)
if part is not None:
setattr(mob, name.lower(), part)
verify.next_to(sign, DOWN, MED_LARGE_BUFF, LEFT)
VGroup(sign, verify).to_corner(UP+RIGHT)
private_key = self.private_key_rects[0]
public_key = self.public_keys[0]
message = self.documents[0]
signature = self.signatures[0]
self.play(*[
FadeIn(part)
for part in sign
if part not in [sign.message, sign.sk, sign.signature]
])
self.play(ReplacementTransform(
message.copy(), VGroup(sign.message)
))
self.dither()
self.play(ReplacementTransform(
private_key.copy(), sign.sk
))
self.dither()
self.play(ReplacementTransform(
VGroup(sign.sk, sign.message).copy(),
VGroup(sign.signature)
))
self.dither()
self.play(Indicate(sign.sk))
self.dither()
self.play(Indicate(sign.message))
self.dither()
self.play(*[
FadeIn(part)
for part in verify
if part not in [
verify.message, verify.signature,
verify.pk, verify[-1]
]
])
self.dither()
self.play(
ReplacementTransform(
sign.message.copy(), verify.message
),
ReplacementTransform(
sign.signature.copy(), verify.signature
)
)
self.dither()
self.play(ReplacementTransform(
public_key.copy(), VGroup(verify.pk)
))
self.dither()
self.play(Write(verify[-1]))
self.dither()
class TryGuessingDigitalSignature(Scene):
def construct(self):
pass
class SupplementVideoWrapper(Scene):
def construct(self):
pass

View file

@ -14,16 +14,16 @@ class TexSymbol(VMobjectFromSVGPathstring):
#TODO, this assumes a = 0
if b < 0.5:
b = 2*b
width = 1
added_width = 1
opacity = 0
else:
width = 2 - 2*b
added_width = 2 - 2*b
opacity = 2*b - 1
b = 1
VMobjectFromSVGPathstring.pointwise_become_partial(
self, mobject, 0, b
)
self.set_stroke(width = width)
self.set_stroke(width = added_width + mobject.get_stroke_width())
self.set_fill(opacity = opacity)
@ -191,7 +191,6 @@ class TextMobject(TexMobject):
"alignment" : "\\centering",
}
class Brace(TexMobject):
CONFIG = {
"buff" : 0.2,
@ -254,9 +253,6 @@ class Brace(TexMobject):
vect = self.get_tip() - self.get_center()
return vect/np.linalg.norm(vect)
def tex_hash(expression, template_tex_file):
return str(hash(expression + template_tex_file))

View file

@ -1,4 +1,4 @@
\documentclass[12pt]{beamer}
\documentclass[preview]{standalone}
\usepackage[english]{babel}
\usepackage[utf8x]{inputenc}
@ -8,23 +8,12 @@
\usepackage{setspace}
\usepackage{tipa}
\usepackage{relsize}
\mode<presentation>
{
\usetheme{default} % or try Darmstadt, Madrid, Warsaw, ...
\usecolortheme{default} % or try albatross, beaver, crane, ...
\usefonttheme{serif} % or try serif, structurebold, ...
\setbeamertemplate{navigation symbols}{}
\setbeamertemplate{caption}[numbered]
}
\usepackage{mathrsfs}
\usepackage{calligra}
\begin{document}
\centering
\begin{frame}
\begin{align*}
YourTextHere
\end{align*}
\end{frame}
$\displaystyle YourTextHere$
\end{document}

View file

@ -1,4 +1,4 @@
\documentclass[12pt]{beamer}
\documentclass[preview]{standalone}
\usepackage[english]{babel}
\usepackage[utf8x]{inputenc}
@ -9,19 +9,11 @@
\usepackage{tipa}
\usepackage{relsize}
\usepackage{textcomp}
\usepackage{mathrsfs}
\usepackage{calligra}
\mode<presentation>
{
\usetheme{default} % or try Darmstadt, Madrid, Warsaw, ...
\usecolortheme{default} % or try albatross, beaver, crane, ...
\usefonttheme{serif} % or try serif, structurebold, ...
\setbeamertemplate{navigation symbols}{}
\setbeamertemplate{caption}[numbered]
}
\begin{document}
\begin{frame}
YourTextHere
\end{frame}
YourTextHere
\end{document}