<s>
Replayable	O
CCA	O
security	O
(	O
RCCA	B-General_Concept
security	I-General_Concept
)	O
is	O
a	O
security	O
notion	O
in	O
cryptography	O
that	O
relaxes	O
the	O
older	O
notion	O
of	O
Security	O
against	O
Chosen-Ciphertext	O
Attack	O
(	O
CCA	O
,	O
more	O
precisely	O
adaptive	O
security	O
notion	O
CCA2	O
)	O
:	O
all	O
CCA-secure	O
systems	O
are	O
RCCA	O
secure	O
but	O
the	O
converse	O
is	O
not	O
true	O
.	O
</s>
