diff --git a/CMakeLists.txt b/CMakeLists.txt
index bae87e3..2a25057 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,9 +4,9 @@
 enable_testing()
 
 if(CMAKE_COMPILER_IS_GNUCC)
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -W -Wdeclaration-after-statement")
-  set(CMAKE_C_FLAGS_DEBUG "-g -O0")
-  set(CMAKE_C_FLAGS_COVERAGE "-g -O0 -fprofile-arcs -ftest-coverage -lgcov")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O2 -Wall -Wextra -W -Wdeclaration-after-statement")
+  set(CMAKE_C_FLAGS_DEBUG "-g3 -O0")
+  set(CMAKE_C_FLAGS_COVERAGE "-g3 -O0 -fprofile-arcs -ftest-coverage -lgcov")
 endif(CMAKE_COMPILER_IS_GNUCC)
  
 if(CMAKE_BUILD_TYPE STREQUAL "Coverage")
diff --git a/library/Makefile b/library/Makefile
index cd25c51..7983f7b 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -5,7 +5,7 @@
 # environment
 #
 CFLAGS	+= -I../include -D_FILE_OFFSET_BITS=64 -Wall -W -Wdeclaration-after-statement
-OFLAGS	= -O
+OFLAGS	= -O2
 
 ifdef DEBUG
 CFLAGS += -g3
diff --git a/programs/Makefile b/programs/Makefile
index adc66ce..9b0d1f5 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -4,7 +4,7 @@
 # To compile with PKCS11: add "-lpkcs11-helper" to LDFLAGS
 
 CFLAGS	+= -I../include -D_FILE_OFFSET_BITS=64 -Wall -W -Wdeclaration-after-statement
-OFLAGS	= -O
+OFLAGS	= -O2
 LDFLAGS	+= -L../library -lpolarssl $(SYS_LDFLAGS)
 
 ifdef DEBUG
diff --git a/tests/Makefile b/tests/Makefile
index 2ebb9f5..4c97aa5 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -6,7 +6,7 @@
 CFLAGS	+= -I../include -D_FILE_OFFSET_BITS=64 -Wall -W -Wdeclaration-after-statement \
 			-Wno-unused-function -Wno-unused-value
 
-OFLAGS	= -O
+OFLAGS	= -O2
 LDFLAGS	+= -L../library -lpolarssl $(SYS_LDFLAGS)
 
 ifdef DEBUG