OP_CAT Proposal to Bring Smart Contracts to Bitcoin Finally Gets a ‘BIP Number’

A
serious
attempt
to
bring
Ethereum-like
smart
contract
functionality
to
Bitcoin
called
OP_CAT
has
finally
been
granted
a
“BIP
number:”

347.
This
is
the
first
step
towards
actually
launching
the
long-proposed
software
upgrade.

“Getting
a
BIP
number
does
not
signal
any
sort
of
consensus
on
the
part
of
the
community,”
Ethan
Heilman,
one
of
the
co-authors
of
the
proposal
alongside
Armin
Sabouri,
said
in
an
interview.
“It
just
makes
discussing
and
writing
software
around
the
proposal
easier
because
the
proposal
now
has
a
unique
numeric
identifier
that
everyone
agrees
on.”

In
other
words,
getting
assigned
BIP
347
means
the
argument
over
the
controversial
proposal
can
finally
begin
in
earnest.

On
one
side
are
those
who
want
to
reserve
the
Bitcoin
network
simply
for
monetary
transactions;
on
the
other
are
those
who
want
to
build
new
things
on-chain,
of
which
proponents
of
OP_CAT
are
just
a
sliver.

OP_CAT
has
a

long
history
in
Bitcoin
circles.
Initially
included
as
one
of
the
first
op_codes
(essentially
programming
shortcuts
built
into
Bitcoin),
Satoshi
Nakamoto
himself
removed
the
functionality
in
2010
after
concerns
were
raised
about
excessive
memory
usage
and
the
possibility
of
introducing
vulnerabilities.

But
in
recent
years,
especially
following
the
release
of
the
Ordinals
protocol
that
reinvigorated
developers’
desire
to
build
on-chain,
proponents
have
returned
to
OP_CAT
as
a
possible
way
to
increase
the
amount
of
things
that
can
be
built
using
Bitcoin.
Other
proposals
include
things
like
Bitcoin
developer
Jeremy
Rubin’s
CTV
and
feature-rich
scaling
solutions
like
Stacks
and
Ark.

See
also:



Bitcoin
L2
Stacks
Is
Getting
a
Major
Overhaul

Heilman
and
Sabouri
began
studying
reintroducing
OP_CAT
in
2022,
and
first
proposed
launching
it
a
year
later
on
the
Bitcoin
Mailing
List
via
a
backward-compatible
soft
fork.
The
idea
would
be
to
redefine
and
expand
upon
an
existing
code
called

“OP_SUCCESS126,”
without
having
to
hard
fork
the
chain.

If
the
proposal
goes
through,
OP_CAT
covenants
could
enable
the
creation
of
more
sophisticated
applications
and
multi-signature
setups
on
Bitcoin.
It
works
by
introducing
“covenants,”
or
rules
that
can
be
established
to
determine
how
a
specific
transaction
will
function,
to
Bitcoin.

“Bitcoin
allows
users
to
set
rules
on
who
and
how
their
bitcoins
can
be
spent.
All
CAT
does
is
that
it
joins
two
values
together.
So
if
you
have
‘abc’
and
‘def,’
CAT
will
join
these
two
values
together
to
make
‘abcdef,’”
Heilman
said,
adding
that
such
a
basic
maneuver
isn’t
possible
today.
“The
CAT
is
just
shorthand
for
conCATenate.”

“After
the
community
is
confident
the
software
works
as
designed,
we
will
put
together
a
PR
into
bitcoin-core.
This
is
where
the
real
fun
begins
because
the
question
changes
from
‘is
the
software
correct?’
to
‘does
the
Bitcoin
community
want
OP_CAT?,’”
Heilman
said.
“This
could
be
a
quick
process
or
it
could
take
years.”

Among
the
biggest
proponents
of
OP_CAT
have
been
the
co-founders
of
popular
Ordinals
project
Taproot
Wizards,
Eric
Wall
and
Udi
Wertheimer,
who
created
the
Quantum
Cats
inscriptions
project
as
a
sort
of

marketing
campaign
for
Heilman
and
Sabouri’s
proposal.

While
Quantum
Cats
is
one
of
the
most
popular
inscription
projects
to
date,
OP_CAT
itself
is
far
from
universally
accepted.
There
is
some
speculation,
for
instance,
that
despite
Heilman
and
Sabouri
submitting
their
BIP
proposal
several
months
ago,
it
was
being
held
off
from
approval
by
lone
BIP
editor
and
Bitcoin
Core
dev
Luke
Dashjr,
who
is
not
alone
in
his
skepticism
of
recent
on-chain
experimentation.

On
Monday,
the
Bitcoin
community
named
five
additional
BIP
editors.
According
to
GitHub,
OP_CAT’s
BIP
number
was
assigned
by
an
editor
who
goes
by
“Roasbeef.”

See
also:
See
also:



Will
Bitcoin’s
New
BIP
Editors
Streamline
Development?

Heilman
said
that
now
that
OP_CAT
has
a
BIP
number,
it’s
up
to
the
community
to
determine
whether
it
should
move
forward.

“Speaking
only
for
myself,
at
this
point
I
plan
to
remove
myself
from
the
process
and
let
the
community
debate
if
OP_CAT
is
something
they
want
or
not
want,”
he
said.
“I
don’t
plan
to
enter
that
debate
except
if
needed
to
clarify
technical
questions.”