<s>
A	O
BLS	B-Algorithm
digital	I-Algorithm
signature	I-Algorithm
—	O
also	O
known	O
as	O
Boneh	B-Algorithm
–	I-Algorithm
Lynn	I-Algorithm
–	I-Algorithm
Shacham	I-Algorithm
(	O
BLS	B-Algorithm
)	O
—	O
is	O
a	O
cryptographic	O
signature	O
scheme	O
which	O
allows	O
a	O
user	O
to	O
verify	O
that	O
a	O
signer	O
is	O
authentic	O
.	O
</s>
<s>
Working	O
in	O
an	O
elliptic	O
curve	O
group	O
provides	O
some	O
defense	O
against	O
index	O
calculus	O
attacks	O
(	O
with	O
the	O
caveat	O
that	O
such	O
attacks	O
are	O
still	O
possible	O
in	O
the	O
target	O
group	O
of	O
the	O
pairing	O
)	O
,	O
allowing	O
shorter	O
signatures	O
than	O
FDH	B-Algorithm
signatures	O
for	O
a	O
similar	O
level	O
of	O
security	O
.	O
</s>
<s>
Signatures	O
produced	O
by	O
the	O
BLS	B-Algorithm
signature	I-Algorithm
scheme	O
are	O
often	O
referred	O
to	O
as	O
short	O
signatures	O
,	O
BLS	B-Algorithm
short	O
signatures	O
,	O
or	O
simply	O
BLS	B-Algorithm
signatures	I-Algorithm
.	O
</s>
<s>
The	O
signature	O
scheme	O
is	O
provably	O
secure	O
(	O
the	O
scheme	O
is	O
existentially	O
unforgeable	O
under	O
adaptive	O
chosen-message	O
attacks	O
)	O
in	O
the	O
random	B-Application
oracle	I-Application
model	I-Application
assuming	O
the	O
intractability	O
of	O
the	O
computational	O
Diffie	O
–	O
Hellman	O
problem	O
in	O
a	O
gap	O
Diffie	O
–	O
Hellman	O
group	O
.	O
</s>
<s>
By	O
2020	O
,	O
BLS	B-Algorithm
signatures	I-Algorithm
were	O
used	O
extensively	O
in	O
version	O
2	O
(	O
Eth2	O
)	O
of	O
the	O
Ethereum	B-Application
blockchain	B-Application
,	O
as	O
specified	O
in	O
the	O
IETF	O
draft	O
BLS	B-Algorithm
signature	I-Algorithm
specification	O
—	O
for	O
cryptographically	O
assuring	O
that	O
a	O
specific	O
Eth2	O
validator	O
has	O
actually	O
verified	O
a	O
particular	O
transaction	O
.	O
</s>
<s>
The	O
use	O
of	O
BLS	B-Algorithm
signatures	I-Algorithm
in	O
Ethereum	B-Application
is	O
considered	O
a	O
solution	O
to	O
the	O
verification	O
bottleneck	O
only	O
for	O
the	O
medium	O
term	O
,	O
as	O
BLS	B-Algorithm
signatures	I-Algorithm
are	O
not	O
quantum	O
secure	O
.	O
</s>
<s>
Over	O
the	O
longer	O
term	O
—	O
say	O
,	O
2025	O
–	O
2030	O
—	O
STARK	O
aggregation	O
is	O
expected	O
to	O
be	O
a	O
drop-in	O
replacement	O
for	O
BLS	B-Algorithm
aggregation	O
.	O
</s>
