<s>
SixChat	O
uses	O
the	O
company	O
’s	O
Identity	O
Registration	O
Protocol	O
(	O
IANA	O
assigned	O
port	O
4604	O
)	O
for	O
address	O
registry	O
and	O
retrieval	O
,	O
as	O
well	O
as	O
Public	B-Architecture
Key	I-Architecture
Infrastructure	I-Architecture
functions	O
(	O
to	O
obtain	O
and	O
use	O
client	O
digital	O
certificates	O
)	O
.	O
</s>
