<s>
The	O
Enrollment	B-Protocol
over	I-Protocol
Secure	I-Protocol
Transport	I-Protocol
,	O
or	O
EST	O
is	O
a	O
cryptographic	O
protocol	O
that	O
describes	O
an	O
X.509	O
certificate	B-Protocol
management	I-Protocol
protocol	I-Protocol
targeting	O
public	B-Architecture
key	I-Architecture
infrastructure	I-Architecture
(	O
PKI	O
)	O
clients	O
that	O
need	O
to	O
acquire	O
client	O
certificates	O
and	O
associated	O
certificate	B-Architecture
authority	I-Architecture
(	O
CA	B-Architecture
)	O
certificates	O
.	O
</s>
<s>
EST	O
has	O
been	O
put	O
forward	O
as	O
a	O
replacement	O
for	O
SCEP	B-Protocol
,	O
being	O
easier	O
to	O
implement	O
on	O
devices	O
already	O
having	O
an	O
HTTPS	O
stack	O
.	O
</s>
<s>
EST	O
uses	O
HTTPS	O
as	O
transport	O
and	O
leverages	O
TLS	B-Protocol
for	O
many	O
of	O
its	O
security	O
attributes	O
.	O
</s>
<s>
API	O
Endpoint	O
Operation	O
Description	O
/.well-known/est/cacerts	O
Distribution	O
of	O
CA	B-Architecture
Certificates	I-Architecture
The	O
EST	O
client	O
can	O
request	O
a	O
copy	O
of	O
the	O
current	O
CA	B-Architecture
certificates	I-Architecture
with	O
HTTP	O
GET	O
operation	O
(	O
RFC	O
7030	O
Section	O
4.1	O
)	O
.	O
</s>
<s>
/.well-known/est/serverkeygen	O
Server-Side	O
Key	O
Generation	O
An	O
EST	O
client	O
may	O
request	O
a	O
private	O
key	O
and	O
associated	O
certificate	O
from	O
an	O
EST	O
server	O
using	O
an	O
HTTPS	O
POST	O
operation	O
(	O
RFC	O
7030	O
Section	O
4.4	O
)	O
/.well-known/est/csrattrs	O
CSR	O
Attributes	O
CA	B-Architecture
policy	O
may	O
allow	O
inclusion	O
of	O
client-provided	O
attributes	O
in	O
certificates	O
that	O
it	O
issues	O
,	O
and	O
some	O
of	O
these	O
attributes	O
may	O
describe	O
information	O
that	O
is	O
not	O
available	O
to	O
the	O
CA	B-Architecture
.	O
</s>
<s>
In	O
addition	O
,	O
a	O
CA	B-Architecture
may	O
desire	O
to	O
certify	O
a	O
certain	O
type	O
of	O
public	O
key	O
and	O
a	O
client	O
may	O
not	O
have	O
a	O
priori	O
knowledge	O
of	O
that	O
fact	O
.	O
</s>
<s>
Therefore	O
,	O
clients	O
SHOULD	O
request	O
a	O
list	O
of	O
expected	O
attributes	O
that	O
are	O
required	O
,	O
or	O
desired	O
,	O
by	O
the	O
CA	B-Architecture
in	O
an	O
enrollment	O
request	O
or	O
if	O
dictated	O
by	O
local	O
policy	O
.	O
</s>
<s>
The	O
basic	O
functions	O
of	O
EST	O
were	O
designed	O
to	O
be	O
easy	O
to	O
use	O
and	O
although	O
not	O
a	O
REST	B-Protocol
API	I-Protocol
,	O
it	O
can	O
be	O
used	O
in	O
a	O
REST-like	O
manner	O
using	O
simple	O
tools	O
such	O
as	O
OpenSSL	B-Language
and	O
cURL	B-Language
.	O
</s>
<s>
The	O
issued	O
certificate	O
,	O
returned	O
as	O
a	O
Base64	O
encoded	O
PKCS	B-General_Concept
#7	I-General_Concept
message	O
,	O
is	O
stored	O
as	O
device-p7.b64	O
.	O
</s>
