►
Description
Sia Co-Founder David Vorick (https://twitter.com/@DavidVorick) and NEAR Co-Founder Alex Skidanov (https://twitter.com/AlexSkidanov) discuss how Sia's technology works in the 30th episode of the Whiteboard Session. Sia is a decentralized data storage platform powered by blockchain technology.
------- About Whiteboard Series ---------
The Whiteboard Series with NEAR is a set of video interviews with Founders who are building scalable solutions for Blockchain. We deep dive into their story, what they're developing and how it is helping the ecosystem.
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B
B
We
really
took
inspiration
from
Bitcoin
and
the
idea
that
you
can
create
a
banking
infrastructure
or
a
financial
infrastructure
with
no
trusted
third
party,
and
so
we
asked
the
question:
could
this
be
applied
to
something
else
and
in
the
case
of
SIA,
where
we're
applying
that
to
you
can
create
a
cloud
storage
platform
that
has
no
trusted
third
party,
and
so
our
goal
is
to
be
able
to
make
it
for
you
to
put
data
into
the
cloud
without
having
to
give
up
control
to
like
say
in
Amazon
or
an
Apple
or
Google.
We
want.
B
We
want
you
to
be
able
to
use
the
cloud
without
having
to
trust
anyone
else
and
and
SIA
launched
in
2015.
We've
been
building
and
enhancing
it
ever
since,
and
I
do
think.
We've
achieved
the
goal
at
this
point
of
decentralized
cloud
storage.
So
I
would
say
that
it's
here
today
it
works
and
you
can
try
it
out.
Cool.
B
So
the
first
thing
to
know
is
that
size,
a
proof-of-work,
blockchain
I,
don't
know
what
I'm
gonna
write
at
this
exact
moment,
but
it
is
a
consensus
system
very
similar
to
Bitcoin.
We
have
one
special
edition
called
the
file
contract
so
rather
than
use
a
like
whole
smart
contracting
platform,
we
thought
the
complexity
was
high.
We
felt
to
make
the
cyanine
work.
B
B
So
what
this
does
is
this
file
contract
has
a
size
and
a
merkel
route
in
it,
and
so
the
size
is
how
much
data
is
in
there.
The
merkel
route
is
the
merkel
route
of
the
data.
So
we
take,
we
take
the
data
and
we
merkel
eyes
it.
We
put
it
into
a
Merkle
tree.
We
take
the
route
and
we
put
that
here
and
so
the
size
for
this
guy
would
be
4
and
then.
B
It
yeah
so
each
each
leaf
is
a
64
byte,
64
byte,
set
of
data
that
you
hatch
and
then
so.
Each
each
node
or
branch
is
32
bytes
of
data
and
then,
of
course,
the
route
is
32
bytes.
So
you
have
64
bytes
into
a
32
byte
leaf.
Then
you
combine
all
the
Leafs
into
a
root.
So
oh
and
then,
and
then
there's
a
time.
B
We
call
it
a
start
time
and
an
end
time
will
come
come
back
to
time
in
a
moment.
So
what
the
money
is
is
money
from
the
renter.
This
is
getting
paid
to
the
host.
So
as
long
as
the
host
is
honest
and
delivers
on
the
file
storage
promise,
the
host
will
get
this
money
and
then
yeah.
This
money
from
the
host
is
actually
like
its
collateral.
So
it's
a
promise
to
the
renter.
B
B
No,
they
get
destroyed,
and
this
is
a
game
theory
optimization.
What
we
don't
want
is
if
the
money
goes
back
to
the
renter
and
let's
say
the
renter
has
some
pretty
big
storage
bills.
You
know
hundreds
of
thousands
of
dollars
owed
to
hosts.
Now
the
renter
has
a
incentive
to
make
the
hosts
fail.
The
renter
can
get
substantial
revenue
or
substantial
cash
back
by
seeing
the
host
fail.
So
we
want
to
make
sure
that
there's
never
any
incentive
to
attack
the
host.
Nobody
wins
when
the
host
loses.
Oh.
B
A
B
It's
much
more
indirect
and
that
would
require
a
much
much
bigger
attack
to
be
profitable,
okay,
so
we'll
dive
into
the
start
time
and
end
time.
So
this
is
this
is
how
how
do
we
know
that
the
host
is
storing
the
data,
so
the
host
has
this
merkel
root,
that
micro
root
and
size
that
describe
the
data,
that's
being
stored
and
a
start
time
and
end
time.
So
the
start
time
might
be,
let's
say,
10,000
blocks
in
the
future
and
then
time
might
be
ten
thousand
two
hundred
eighty
eight
blocks
in
the
future.
B
Some
quick
context:
sia
blocks
are
ten
minutes
just
like
Bitcoin.
So
two
hundred
eighty
eight
blocks
is
two
days.
So
the
start
time
is
when
the
host
has
the
opportunity
to
provide
a
storage
proof
and
the
end
time
is
when
the
network
assumes
that
the
host
was
unable
to
provide
the
storage
proof.
So
we
don't
want
the
host
to
provide
a
storage
proof
earlier,
because
then
that
doesn't
the
host
hasn't
stored.
The
data
for
for
enough
time
hasn't
fulfilled
their
commitment,
but
we
want
to
make
sure
they
have.
B
B
B
Equals
you
know,
ABCD
we're
going
to
take
the
hash
of
this
h
of
ABCD
and
we're
going
to
turn
that
into
a
random
number
RNG
we're
going
to
use
the
random
number
to
select
one
of
these
and
random.
So
let's
say
this
one
gets
chosen
so
now
the
host
has
to
provide
a
proof
on
this
node
that
he
has
this
data
in
particular.
So
this,
if
you
remember,
corresponds
to
64
bytes.
So
the
host
is
going
to
provide
this
64
bytes,
not
the
hash
of
them,
but
what
the
actual
bytes
themselves
mm-hmm.
B
Going
to
provide
see
what
would
that
be
that
movies,
the
Merkle
proof
that
the
64
bytes
belongs
in
the
merkel
root
in
the
contract,
and
so
this
is
a
probabilistic
proof.
If
the
host
can
present
this
proof,
then
we
accept
it
as
though
the
host
proved
they
have
all
the
data.
If
the
host
cannot
present
this
proof,
then
we
assume
the
host
doesn't
have
any
data
at
all,
even
if
they
have
other
the
host
knows
no
has
one
one
chance
to
prove
they
have
the
state
and.
A
B
Yeah,
and
so
if,
if
we
get
to
10,000
288
and
no
proof
has
shown
up
yet,
then
the
contract
will
destroy
all
the
money
mm-hmm.
If
we
do
get
a
proof
in
this
range,
though,
obviously,
because
we
use
this
block
to
figure
out
what
what
the
challenge
is,
the
hosts
unable
to
provide
a
proof
until
this
height
mm-hmm
cuz,
the
host
doesn't
know
where
the
challenge
is
going
to
be.
This
is
a
secure,
random
number,
but.
A
B
So,
and
that's
that's
precisely
the
argument,
so
the
hash
of
a
block
is
AC
is
a
secure,
random
number
in
the
sense
that
it's
expensive
to
try
again
and
each
time.
If
you
don't
like
the
random
number,
you
get,
you
can
roll
again
and
it's
gonna
cost
you
whatever
the
block
reward
is
so
if
the
block
reward
is
say
$400,
it's
gonna
cost
you
$400
to
try
and
get
her
in
another
random
number.
B
Now,
if
you're,
the
network's
busy,
if
you're
a
host
with
say,
200
storage
proofs-
and
you
have
a
ran,
a
number
that
that's
selects
on
all
200,
what
are
the
chances
that
you're
gonna
roll
another
random
number,
if
you're
trying
to
cheat?
What
are
the
chances
that
your
next
random
number
is
going
to
be
good
across
all
200
contracts?
B
Today,
that's
probably
a
bad
idea,
but
if
you
have
contracts,
even
that,
are
you
know
in
the
thousands
of
dollars
probabilistically,
it
should
be
fine,
it's
more
expensive
to
manipulate
the
random
number,
even
if
you
assume
a
100
percent
minor
than
it
is
to
just
store
all
the
data.
Mm-Hmm
cheating
is
very
expensive,
so
the
other,
the
other
trick
that
we
use
is
the
collateral.
B
So
we
can.
We
can
prove
that
as
long
as
the
host
is
putting
up
more
than
one
X
collateral,
the
expected
value
of
cheating
is
lower
than
the
expected
value
of
or
the
yeah.
The
expected
penalty
of
cheating
is
lower
than
the
expected
costs
of
just
continuing
to
store
the
data,
and
so
one
like
subtle
corner
of
the
network
is
actually
when
the
price
drops,
because
the
reward
is
tracked
in
SIA
coin.
So
if
the
cycloid
price
goes
way
down,
the
host
reward
goes
way
down.
B
B
This
ratio
is
still
safe
if
you
were
doing
like
1000
and
and
1000,
this
ratio
may
not
be
safe,
be
because
now
what
now
that
it's
fallen
in
half
the
host
can
go
to
someone
else
and
get
2000
signs
for
the
same
amount
of
storage,
and
so
you
want
your
collateral.
Multiple
to
you
want
to
take
into
account
network
volatility.
So
this
is
one
things
where
SIA
tries
to
avoid
volatility
in
its
token
price,
if
we
could
have
a
stable
coin,
I
think
that
would
be
best
of
all.
B
C
B
Then
it's
then
it's
not
safe
and
that
actually
is
a
function
of
how
old
the
contract
is.
So
if
the
contract
is
like
has
3%
transpired,
then
probably
not
safe,
but
if
the
contract
is
99%
transpired,
the
host
only
has
2
or
even
like
50%
transpired.
The
the
host
only
has
to
hold
the
data
for
half
the
time
of
the
contract.
If
they
go
to
someone
else,
they're
going
to
have
to
spend,
you
know,
say
double
or
yeah
that
someone
else
is
going
to
have
to
compensate
for
more
time
and
so.
A
B
And
so
the
renter
should
assume
that
as
soon
as
as
soon
as
this
height
hits,
the
host
is
going
to
make
the
proof
and
delete
the
data
and
in
reality
the
host
is
going
to
wait
a
little
bit
in
case
there's
a
reorg
or
something.
So
the
host
does
wait
to
submit
the
proof,
but
the
renter
has
no
control
over
that.
The
host
doesn't
have
to
wait
depending
on
the
hosts
model
of
the
network,
but.
A
B
So
that
is
purely
revenue
based
thing,
so
every
time
that
you
we've
tried
to
structure
the
sign
at
work
so
that
every
time
you
spend
resources
on
the
side
net
work
you
pay
for
them.
So
upload
bandwidth,
download,
bandwidth,
storage,
cost
contract
fees
write
this
the
host
has
to
get
a
storage
proof
onto
the
blockchain.
That's
a
resource
that
the
host
that's
a
cost
that
the
host
incurs
when
it
enters
into
a
file
contract,
so
the
renter
actually
pre
pays
for
that.
B
B
So
if
I'm,
a
third
party
like
any
anyone
looking
at
the
blockchain
anyone
trying
to
verify
the
blockchain
as
a
third
party,
so
if
you
and
I,
if
you're
a
host
I'm
a
renter
and
I,
say
to
the
network,
he's
not
sending
me
the
data,
but
then
every
time
I,
try
and
like
this.
Is
the
data
he's
not
sending
me,
and
you
just
proved
it
you.
You
prove
the
network
that
you
have
it
there's
no
way
for
me
to
prove
that
you
are
not
sending
the
data
you
can
always.
B
You
can
always
withhold
until
the
last
second
and
then
give
it
to
me
or
I.
Could
just
like
falsely
claim
that
you're
not
sending
me
the
data.
We
can't
resolve
who's
who's.
Being
honest
in
a
disagreement
like
that,
so
we
have
to
use
other
means.
Then
we
can't.
We
can't
slash
people
for
not
making
data
available,
because
we
can't
prove
that
they
are
actually
not
making
data
available.
We
can
only
prove
whether
or
not
they're
actually
storing
it.
B
That's
what
we
do
instead
is
we
fall
back
on
redundancy,
so
we
store.
This
is
its
own
thing,
so
I
think
remove
on
from
file
contracts.
For
now
we
will
come
back
to
state
channels,
so
our
file
contracts
are
actually
state
channels.
This
is
a
scalability,
optimization
and
a
super
important
one
that
that
is
like
fundamental.
It's
making,
scienc
callable
or
Oh
redundancy,
okay.
So
every
single
we
use
something
called
reed-solomon
code.
B
It's
a
que
and
redundancy
scheme,
so
I'll
take
a
piece
of
data,
I'll
split
it
up
into
K
pieces
on
the
sign
at
work.
Today,
it's
a
ton
of
30
I'm
gonna
go
ahead
and
draw
two
of
six
just
because
it's
less
things
to
draw,
so
we
end
up
with
do
it
this
way.
So
we
end
up
with
six
pieces
of
data
out
of
these
six
pieces
of
data,
two
of
them
and
it
doesn't
matter
which
two
are
all
I
need
to
reconstruct
the
original
data.
B
B
So
we
pick
10
of
30
on
the
side
network,
the
redundancy
overhead.
This
is
called
a
maximum
distance.
Separable
code
is
n,
divided
by
K,
so
on
the
sign
out,
work
that
would
be
30
divided
by
10
equals
3
X
3
X
4
done
in
C.
So
it's
it's.
Basically,
the
same
overhead
is
doing
a
1
of
3
to
do
a
10
of
30,
but
the
difference
is
instead
of
needing
in
a
1
of
3
you're
hosed.
If
you
get
three
rare
events,
three
three
hosts
are
not
responsive
in
a
10
of
30.
A
B
A
B
A
B
A
So
so
far,
it
feels
to
me
that
at
least
one
of
them
should
be
able,
at
some
point
to
to
trick
the
other
right
so
either
so
between
you
and
I
want
to.
Let's
say
you
are
enter
I'm
a
host
right
yeah.
This
is
the
moment
to
an
eye
when
you
actually
receive
the
file,
and
there
is
a
moment
when
you
release
the
payment
to
me
yeah.
There
is
no
way
that
is
atomic
right.
That's
one
of
those
must
happen
before
the
other,
so.
B
Actually,
there
is
a
way
to
make
that
atomic
I'm
not
gonna,
go
into
it,
because
it's
not
how
we
do
it.
So
we
we
do
something
called
packetized
payments.
So
what
the
renter
and
I'll
just
go
ahead
and
use
the
numbers
typically,
so
the
renter
is
going
to
send
payment.
The
first
step
is
the
renter
sense
payment,
whether
it's
a
small
payment.
B
B
Then
the
host
sends
four
megabytes
and
then
we
do
it
again,
and
so,
if
we're
downloading
a
one
gigabyte
file,
we're
gonna
run
this
circle
a
bunch
of
times
if
at
any
point
the
hosts
it
takes
our
payment
and
doesn't
give
us
data
now.
I
know
it's
a
bad
host
yeah
and
because
we're
talking
to
30
different
hosts
one.
This
gives
us
super
super
high
parallelism.
So
even
if
each
host
is
pretty
slow
as
an
aggregate,
the
throughput
is
super
high.
A
B
B
I
think
it's
64
bytes,
so
I
think
our
chunks
are
64
bytes
at
the
at
the
reed-solomon
level
at
the
network,
level
are
chunks,
so
we
take
what
we
do
with
a
large
file.
Let's
say
we
have
a
4
gigabyte
file,
we're
gonna.
Take
this
4
gigabyte
file,
we're
going
to
split
it
into
basically,
so
the
sector
size
on
the
network
is
4
megabytes,
so
we're
gonna
split
it
into
sector
size
times
min
redundancy
in
redundancy
for
just
3
X.
No.
A
C
C
B
B
B
A
B
Because
there
are
state
channels
really
what
you
do
is
before
we
get
into
the
technical
details.
You're
gonna
pick
50
hosts,
so
I'll
just
draw
five
10
10
I,
don't
know
if
that's
time,
2
4,
6,
8,
10,
okay
and
so
we're
gonna.
Have
you
put
the
renter
up
here?
The
renter
is
going
to
form
a
contract
file
contract
with
each
of
the
10
hosts.
Now
it
looks
like
a
spider,
happy
Halloween
and
when
we
upload
a
file,
each
of
these
are
state
channels.
B
B
C
A
B
B
Then
once
we
have
them,
we
can
use
them
to
upload,
essentially
an
unlimited
amount
of
data.
As
far
as
far
as
the
protocol
is
concerned,
as
you
saw,
the
the
file
contract
itself
is
a
constant
size.
It
just
has
a
size
and
a
Merkel
root
that
scales
infinitely.
The
storage
proof
is
logarithmic,
it's
a
Merkle
tree
proof,
so
that
doesn't
scale
infinitely,
but
log
a
a
logarithm
in
a
finite
universe
is
constant
right.
So
by
the
time
you're
up
to
proof
sizes
of
I
think
around
three
kilobytes
you've.
B
C
C
B
Ledger
yeah,
so
so
the
chain
can
handle
effectively
an
infinite
amount
of
data
per
file,
contract
and,
and
the
largest
proof
size
you'll
ever
practically
see
is
4
kilobytes.
But
the
saiga
client
can't
there's
a
lot
of
metadata
it
has
to
manage.
This
is
actually
something
that
we
improved
progressively
so
like.
When
we
first
launched
sia,
we
actually
didn't
have
the
state
channels
up.
So
the
whole
entire
side
network
was
good
for
about
I,
think
10,000
files
and
the
largest
acceptable
file
was
like
50
megabytes.
B
This
was
like
you
know,
2015
and
then
later
in
2015.
Also
in
2015,
we
got
it
up
to
you
know
like
10
million
files
for
the
whole
sign
at
work,
and
then
you
know,
maybe
each
file
could
be
up
to
I.
Think
200
megabytes
today
we're
doing
much
better,
so
each
each
node,
a
single
cyano
today,
is
effectively
good
up
to
around
50,000
files
in
a
single
node
and
then
around
20
terabytes
in
a
secure.
B
If
it's
a
single
file
at
20
terabytes,
you
probably
still
good
and
then
the
20
terabytes
most,
that
limit
comes
from
the
repair
process,
we're
still
ironing
that
out,
we
actually
have.
We
have
an
internal
fix
that
we're
gonna
push
out.
We
don't
know
if
this
it
bumps
this
number
up
or
how
much
it
bumps.
This
number.
C
B
C
C
A
B
So
we
we
have
a
module
that
we
call
a
host
DB
mm-hmm,
as
the
name
suggests.
It
is
a
database
of
hosts
and
the
renter,
so
each
renter
has
their
own
host
DB
the
blockchain.
When
a
host
wants
to
announce
the
network,
it
puts
into
the
blockchain
an
announcement
I'm
a
host
here's,
my
IP
address.
Ask
me
about
my
wares
and,
and
so
the
renter
will
ping
the
host
get
prices
availability.
B
You
know
whatever
a
bunch
of
statistics
and
then
that
renter
keeps
in
its
database
just
a
big
list
of
how
good
each
host
is,
and
so,
if
it's
using
as
it
starts
to
use
house,
it
gets
better
data
if
it
noticed
that
a
host
is
slower
or
is
withholding
data
or
otherwise
unavailable
it
down
ranks
it
in
the
host
DB.
And
so,
if
you
are.
A
B
Will
yes,
so
that's
called
the
repair
process,
so
let's
say
that
the
renter
decides
a
particular
host
is
bad,
whether
it's
because
it's
offline,
it
increased
prices.
It
you
know
there
are.
There
are
a
number
of
triggers
that
could
cause
the
renter
to
decide
a
hostess
bad.
Basically,
what
it
does
is
it
will
when
it
wants
to
do
a
repair
it
will
download
the
file.
B
So
if
we're,
if
we're
doing
a
ton
of
30
scheme,
it'll
find
10
pieces,
download
them
reconstruct
the
original
30
and
then
whatever
hosts
need
replacing
it
will
find
new
hosts
and
replace
those.
It
will
only
do
that
once
25%
of
the
redundancy
is
missing,
so
25%
is
missing
in
so
the
redundancy
in
our
case
is
20
pieces
right.
We
call
them
parity
pieces
fun
of
you.
Parity
pieces
I
spelled
that
that's
ok
times.
B
Percent
of
all
D,
ok,
all
the
pieces,
just
just
25%
of
the
parity,
so
once
five
hosts
are
bad
on
a
particular
file,
it
will
go
ahead,
download
that
file
replace
those
five
pieces,
whichever
whichever
five
are,
the
bad
ones,
it'll,
replace
them,
upload
them
to
new
hosts,
and
so
the
the
renter
is
constantly
doing
this.
We
call
it
churn
just
constantly
doing
this
repair
churn
and
obviously
that's
can
be
a
scalability
limitation
if
it's
happening
a
lot,
but.
A
B
A
Because
I
presume
oh
but
I
see
so
the
so
let's
say:
I'm
running
a
host
machine,
yeah
right
and
oh
yeah.
So
that's
that's.
What
is
not
very
nice
idea
and
the
host
machine
I'm
a
host
motion
crushed
and
I'm
in
Hawaii?
Yes,
I'm,
not
in
a
particular
hurt
to
recover
it
I
need
to
recover
it
the
first
time
my
next
file
contract
expires
right,
No.
B
B
So
if
you're
offline
for
more
than
5%
of
a
single
month,
which
is
about
1
day,
so
you
can,
you
can
afford
to
lose
about
one
day
of
downtime
in
a
row.
The
renter
will
start
to
penalize
you
and
will
start
to
turn
you,
and
so,
if
a
renter
is
active,
is
constantly
uploading
new
data,
it's
constantly
repairing
if
you're
a
host-
and
you
have
downtime
all
the
renters
who
are
using
you
are
starting
to
down
rank
you
all.
A
Right
what
time
is
ready
so
so
I
will
start
losing
revenue.
What
that
meant
is
that
for
me
to
lose
collateral?
Yes,
it's
it's
like
it's
not
particularly
depressing
I
need
to
recover.
My
you
start
my
note
before
file
contracts
expire.
Yes,
because
that's
a
way,
bigger
loss
for
me
right
Michael
at
you
yep
then
yeah
yeah.
C
B
B
And
that's
actually
one
of
the
reasons
the
network
is
so
cheap
right
who's
like
Amazon
their
data
centers.
They
have
full-time
engineers
that
are
on
site,
24/7,
awake
alert,
trained
technicians.
They
know
how
to
operate
the
datacenter.
They
have
multiple
ISPs,
multiple
power
companies,
our
hosts,
it's
fine.
If
you
go
on
vacation
right
and
then
the
thing
crashes.
C
B
You
have
to
call
your
friend
and
get
it
to
reboot
it
or
whatever,
if
there's
some
like,
if
you're
slower
and
have
less
uptime,
then
Amazon
datacenter.
This
is
seen
as
perfectly
acceptable
because
you're
not
a
single
point
of
failure.
Well,
while
you're
down,
for
you
know,
24
hours,
we
have
29
other
people
right,
but.
A
A
A
We
don't
have
so
one
other
thing
where
I
cannot
see
anything
bad
happening
yet,
but
because
you
thought
more
about
that,
you
probably
know
if
there's
something
happening
there
sure
when
I
send
those
thing
is
right.
Some
of
those
entities
could
be
the
same
entity
right
yes,
could
each,
because
this
is
a
racial
code
that
could
could
they
cheat
in
some
way,
especially
if
it
happens
that
many
of
them
yeah.
B
C
B
They
each
have
one
piece
and
they
know
that
the
pieces
go
together.
They
can't
put
them
together
because
the
encryption
is
applied
after
the
erasure
coding
yep.
So
you
cannot
the
redundancy.
The
renter
has
perfect
confidence
that
the
redundancy
can't
be
cheated
mm-hmm.
This
comes
with
a
trade-off,
and
this
is
actually
like
this
is
this
is
the
trade-off
that
SIA
makes
that
file
coin
does
not
make
that
resulted
in
file
coin.
Doing
like
requiring.
B
You
know
tons
of
open
research
problems,
so
this
this
is
fairly
easy,
but
it
means
that
the
renter
or
someone
that
the
renter
trusts
with
the
encryption
key
is
the
only
one
able
to
do
repair.
So
if
the
renter
is
like
on
vacation-
and
you
know,
three
hosts
disappear,
or
let's
say
you
know,
half
half
the
hosts
disappear
so
now
the
renter
is
in
trouble.
She
needs
to
repair
as
fast
as
possible
if
the
ranch
is
on
vacation.
B
The
network
can't
repair
on
behind
the
renter,
because
the
network
doesn't
know
what
the
encryption
keys
are
so
either
the
renter
themselves
or
someone
that
the
renter
has
trusted.
The
encryption
keys
has
to
be
the
one
to
do
the
repairs,
whereas
file
coin
has
all
these
like
deep
research
questions
that
are
open.
How
do
we
make
it
so
that
we
can
repair
it
without
someone
being
able
to
cheat
and.
B
Yes,
that's
one
option
SGX
and
they
have
a
bunch
of
crypto
protocols,
require
trusted
setup
so
similar
similar
assumptions
to
have
SGX.
In
my
opinion,
regardless,
we
don't
like
that.
We
do
up
here
like
verifiable
route,
we
make
the
trade
off,
the
renter
has
to
be
around
or
someone
they
trust
has
to
be
around
to
do
file,
repairs.
C
B
B
Us
we
observe
when
we
so
we
run
our
own
notes,
writes
we
can
observe
when
we
have
to
deal
with
churn
and
of
course
we
talked
to
our
community,
so
lots
of
people
run
large
nodes
and
actually
right
now
again
we
already
have
the
fix
for
this
in
the
lab,
we're
trying
to
push
it
out.
We
were
trying
to
push
it
out
this
week,
didn't
quite
make
it
maybe
next
week,
but
right
now,
Turin
is
actually
fairly
high
on
the
side
network,
and
this
is
due
to
a
scoring
error.
B
Maybe
twenty
five
percent
per
month,
I
saw
after
after
the
scoring
fix
I,
think
will
be
closer
to
I
predict.
It
will
be
closer
to
five
percent
per
month,
which
is
still
you
know.
If
you
have
a
hundred
terabytes
of
data,
that
means
you're
repairing
five
terabytes
a
month.
That's
still
fairly
substantial,
but
we'll
see
so
churn
is
definitely
like
from
a
scalability
perspective.
That's
probably
the
biggest
bottleneck
is
how
much
repair
bandwidth
do.
You
need
per
terabyte
you
put
on
the
network
every
month,
and
this.
A
B
B
Lose
21
in
a
single
month;
normally
it
would
take
three
three
to
six
months.
One
other
thing
on
the
sign
at
work.
File
contracts
are
typically,
they
typically
lasts
around
three
months,
and
so,
if
you're
gone
for
more
than
three
months,
all
your
file
contracts
expire
host
to
lead
all
the
data.
You
need
to
renew
them.
You
need
to
let
the
hosts
know
you're
still
interested.
You
need
to
repay
to
keep
the
file
contracts
alive.
A
B
So
if
you
want
a
file
contract
that
cannot
be
revised
for
whatever
reason
you
just
set
it
to
you
in
64,
max
that
contract
can't
be
revised
and
practice.
I
think
anyone
does
this
because
I
you,
you
also
there's
also
a
renter,
renter,
private,
key
renter,
public
key
sorry
and
a
host
host
public
key.
So
you
need
signatures
from
both
to
update
anything
yeah.
A
B
Actually,
all
you
have
to
do
so,
there's
also
a
so
there's
a
success.
Success
balance,
so
these
are
I,
see
success.
Pal
success
actually
success
outputs,
so
the
renter
gets
some
money
back.
The
host
gets
the
money
back
and
it's
just
how
much
right
and
then
there's
fail
where
the
renter
gets
the
money
back,
the
host
gets
them,
get
some
money
back
and
so
and
then
and
then
the
void.
That
has
to
add
up
to
that
and
then
there's
an
input.
There's
a
payout
payout
up
here.
These
two
have
to
add
up
to
the
payout.
B
B
A
C
A
A
B
Yeah
so
like
what
what
could
happen?
Is
you
put
a
hundred
signs
into
a
channel
right
and
then
initially,
let's
say
the
we
close
the
contract
super
early.
So
what's
happened
is
the
renter
paid.
You
know
Tennessee
to
the
hosts
so
well,
let
me
break
this
out
a
little
more.
So
we
have
a
file
contract
renter
in
mentor
in
will
call
one
hundred
side.
Coins
hosting,
will
call
210
points.
These
are
recommended
parameters
and
then
what's
going
to
happen
is
if
we've
all
if
the
renter
has
only
stored
a
little
bit,
you
might
have
success.
B
Look
like
this.
Where
it's
renter
gets
back,
the
renter
gets
back.
Ninety
nine
side
coins,
the
host
gets
back,
will
that
be
to
one
side,
coins
go
inside
claims
and
then
fail
would
be
renter
and
two
ninety-nine
side
coins
host
gets
back.
That
would
be
one.
Ninety
eight
SIA
coins
and
then
void
is
going
to
collect
the
rest
for
just
three
side
points.
So.
B
The
host
was
originally
at
two
side:
two
hundred
side
coins,
the
renter,
the
renter
paid
one
side
coin,
to
store
some
amount
of
data.
Oh
those
collateral
and
the
host
put
in
two
signs
of
collateral,
and
so
the
void
gets
three
in
the
in
the
failed
case.
But
if
we
want
to
do
an
early
close,
what
we
would
do
is
we
would
you
know,
X
out
this
fail
or
actually
had?
Okay.
If
we
ignore
this
X,
we
would.
B
A
B
B
Bandwidth
so
a
storage
bandwidth
on
the
sign
at
work.
Today,
our
storage
cost
is
$1
and
20
cents
per
terabyte
per
month.
Upload
bandwidth
costs,
16
cents,
0.16
per
terabyte,
download
bandwidth.
Dl
BW
is
whatever
83
cents,
0.8
3
cents
per
terabyte
on
Amazon.
This
is
I,
believe
$21,
upload,
bandwidth,
I
think
is
free
on
Amazon
I,
don't
I,
don't
think
they
charge
you
to
upload
and
for
download.
B
A
B
B
As
of
writing
this
video,
or
as
it
right
now,
so
you
multiply
this
by
this-
you
see
it's
not
that
much
money
that's
getting
paid
per
month,
but,
as
this
goes
up,
I
think
we'll
see
increasingly
more
and
more
professionals
come
in
they'll
continue
to
push
the
prices
down,
but
the
real,
the
real
cost
advantage.
I
think
for
us
comes
from
a
significant
relaxed
relaxing
of
trust
requirements,
a
significant
reduction
of
barrier
to
entry.
B
So
if
you
have
a
you
know
host
on
a
fast
internet
connection,
you
can
just
buy
some
hard
drives
and
and
offer
them
up
to
network
and
and
then
like
there's,
no
the
up
time
requirements.
Ninety-Five
percent
is
more
than
you
can
do
on
a
laptop,
but
it's
pretty
easy
from
just
any.
You
know
you,
don't
you
don't
need
a
crazy
ISP
or
a
crazy
power
supply
agreement,
cool.
B
B
B
If
I
lose
my
machine,
my
house,
whatever
and
I,
have
to
start
fresh
I
can
grab
a
new
computer.
Download
SIA
put
my
wallet
seat
in
and
this
snapshot
will
show
up
and
all
the
files
listed
in
the
snapshot
will
be
recoverable
and
I
need
to
know
nothing
more
than
my
wallet
seat.
To
get
all
of
my
data
back
and
this
I
think
is
the
feature
that
really
makes
SIA
like
a
viable,
proper
backup
solution.
So
this
is
something
that's
live
today
and
now
I
can
dive
into
kind
of
how
that
works.
B
It's
actually
fairly
complicated
this.
This
was
one
and
this
a
feature
we
added
earlier
this
year.
So
it
took
us
almost
five
years
to
get
saya
to
a
maturity
level
where
I
could.
Where
could
do
this?
Okay,
so
step
one?
Is
we
have
a
blockchain
full
of
information?
This
is
the
blockchain
blockchain
and
in
the
blockchain,
are
all
of
our
file
contracts.
B
B
So
when
we
create
the
file
contracts,
all
transactions
in
SIA
have
this
so
IFC
and
then
so
here's
the
here's
the
file
contract.
They
also
have
something
called
arbitrary
data,
so
inside
the
arbitrary
data.
What
we
do
is
we
put
a
color
color,
which
is
really
just
a
hash
of
our
seed
appended
with
some
extra.
B
This
is
a
little
bit
of
a
simplification,
but
but
let's
say
the
host
pub
key,
the
post
pub
key,
and
so,
if
I
have
my
seed,
I
can
see
in
the
file
contract
with
the
host
pub
key
is
I
know
what
the
color
would
be
of
this
contract
if
it
was
mine
and
importantly
because
it
depends
on
my
seed,
which
is
a
secret,
nobody
else
can
make
a
file
contract
that
I'll
mistakenly
think
has
my
color.
They
don't
know
what
data
they
need.
B
B
Lost
everything,
so
you
have
no
information
at
all,
except
the
blockchain,
which
is
public,
so
we
can
download
the
SIA
client,
which
is
public.
We
can
download
the
blockchain,
which
is
public
and
we
have
our
seed,
but
we
don't
have
an
estate
channel
and
we
don't
have
anything
else.
Besides
our
seed
and
so
from
our
seed.
We
have
to
derive
everything
else,
and
so
this
is
why
the
color
is
important.
B
We
know
our
seed,
we
know
the
host
pub
key
has
to
send
the
file
contract
so
as
we're
scanning
through
we're
gonna,
find
I
think
a
million
file
contracts
in
the
blockchain.
That's
how
many
are
the
blockchain
today
and
so
a
million
times
you're
gonna
check
and
you're
gonna
say:
oh
no.
This
is
not
mine.
This
is
not
mine.
B
B
We've
lost
our
data,
so
yes,
we
we
can
identify
our
final
contracts.
We
know
from
the
public
key
inside
the
blockchain
there's
also
this
public
key
to
IP
address
mapping.
We
know
what
IP
addresses
to
ping,
something
that
we
do
in
our
protocol
is
that
every
time
we
connect
to
a
host,
no
matter
what
we
open,
the
connection
by
pretending,
we've
lost
our
data,
I
see
so
we're
trying
to
connect
we're
trying
to
trick
the
host
into
taking
advantage
of
us
when
I
think.
B
A
B
What
you
can
actually
do
is
you
can
give.
We
don't
do
this
yet.
Thank
you.
This
is
something
we
would
like
to
like
to
add,
but
what
you
can
do
is
you
can
put
the
entire
state
you
put
every
state
channel
on
every
host,
so
every
time
you
connect
to
a
host,
you
can
ask
them
for
all
your
state,
okay,
and
this
actually
creates
an
interest.
It.
B
Yeah,
then
you
can
get
everything
back
and
hosts
are
all
in
competition
with
each
other
right.
So
the
other
people
that
I'm
using
are
this
guys
competition?
This
guy,
you
know
the
honest
host,
actually
kind
of,
has
an
incentive
to
have
his
dishonest
competitors
go
out
of
business,
so
he
actually
wants
to
give
me.
He
may
not
want
to
give
me
my
channel
state
for
him,
but
he
wants
to
give
me
my
channel
state
for
everybody
else.
A
B
It
wasn't
needed
before
we
we've
been
planning
this
for
a
long
time,
so
we've
had
that
behavior
in
the
network
for
a
long
time,
but
we
did
we
did
at
it
specifically
because
we
knew
we
would
need
it
down
the
road
yep
interesting
inside.
So
now
now
we
have
our
file
contracts
back.
We
have
our
state
channels
back.
We
still
need
some
way
to
fetch
the
metadata
and
so
basically,
the
first
a
file
contract
is
okay.
This
is
kind
of
interesting
architectural
stuff.
B
B
So
the
fixed
section
is
where
we
store
a
pointer
to
when
we
created
that
snapshot,
we
actually
uploaded
it
as
a
file
so
somewhere
in
this
random
access
section,
there's
a
there's,
a
file
that
has
you
know,
snapshot
snapshot
and
then
that
snapshot
of
course
ot.
That
snapshot,
of
course,
will
point
to
all
the
other
files.
B
So
here
we
have
a
pointer
and
so
we'll
just
look
at
this
is
index
0,
so
in
index
0
we
have
a
pointer
that
says
this
thing.
This
root
is
a
snapshot,
so
most
of
our
files
are
stored
by
their
merkel
root.
The
host
keeps
the
table
on
its
side,
that
goes
from
merkel
root
to
data,
and
so,
if
I
ask
the
host
for
a
particular
merkel
root,
it
can
give
me
the
data.
B
I
know
that
it
gave
me
the
right
data
because
just
hash
it
up
I
see
if
the
Merkel
routes
match
and
then
what
that
means
is
that
when
we
want
to
do
something
like
deletion,
what
we
can
do,
because
so
if
this,
if
this
is
a
million
nodes
long
which
on
for
some
filed
contracts,
that
that's
four
terabytes
a
million
nodes,
is
four
terabytes.
If
it's
a
million
nodes
long,
we
don't
want
to
have
to
recompute
the
merkel
route
across
four
terabytes
of
data.
That's.
A
B
B
C
B
A
B
Because
then
we
can
repair
the
snapshot,
we
can
make
changes
to
it.
I
say
also:
we
can
make
a
bunch
of
them.
So
if
we
have
like
actually
I
think
I
think
the
correct
answer
is
so
we
can
have
a
bunch
of
them.
If
we
have
50
different
snapshots,
it
becomes
a
pain
to
try
and
front
load,
50
things
and
keep
them
ordered
and
like
and
then
what.
B
Prune
them
or
delete
them
figure
out
how
to
do
that
when
they're
all
in
fixed,
if
you
like
the
snapshots
to
be
random
access.
So
if
we
want
to
shuffle
things
around
mm-hmm,
it's
free
fix
the
fixed
section
everything's
referenced
by
index,
so
it
means
whatever.
Is
there
can't
move,
and
we
have
no
flexibility
to
touch
it?
If
you
delete
something
in
the
middle
of
a
fixed
section,
you
can't
reclaim
that
data.
You
can
only
wait
until
someone
wants
new,
fixed
data,
no.
C
B
Particular
house
are
snapshots,
oh
and
that's
the
other
thing.
So
every
host
has
the
fixed
section.
This
is
replicated.
If
you
have
50
hosts.
Your
fixed
section
is
replicated
across
50
hosts,
but
your
snapshot
can
be
erasure
coded
and
so
the
snapshot,
which
can
be
quite
a
bit
larger.
You
know
the
the
fixed
section,
the
pointer
to
the
snapshot
is,
you
know
either
32
bytes
or
if
you've
erased
your
code,
that
the
snapshot-
maybe
it's
32
times,
50
mm-hmm
bytes,
it's
yeah
32
times,
50
pointers,
but
the
snapshot
itself.
B
B
B
What
this
means
is
that
you
can
mount
SIA
as
a
drive
on
your
computer
as
though
something
like
VLC
or
Plex
Media
Center
will
recognize
the
folder
that
is
actually
a
size
folder
as
a
normal
file
system,
folder
and
so
we're
working
on
an
integration
with
Plex
called
size
stream
that
allows
you
to
put
your
media
library
onto
the
sign
at
work
and
then
stream
from
it
to
any
of
your
any
of
your
Plex
endpoints
and
and
view
your
content.
So
that's
that's
like
one
interesting
use
case
that
we're
we're
rolling
out
design
network
cool.
A
B
And
then,
because
so
the
the
actual
erasure
coding
bits
are
I
think
divisible
down
to
64
bytes
mm-hmm
I,
don't
I,
don't
think
we
have
a
specific
vocab
word
for
the
64
byte
mm-hmm
segments,
but
they,
but
so
if
you
want
just
the
first
like
say,
you
know
two
megabytes
of
a
40
megabyte
chunk
uh-huh
you
can
download
just
the
first
two
bytes
you
don't
have
to
download
the
whole
40
mega
voice.
Oh,
that
makes
it
a
responsive
streaming
platform.