diff --git a/A5_1.c b/a51/A5_1.c
similarity index 96%
rename from A5_1.c
rename to a51/A5_1.c
index a07b484..64b44f7 100644
--- a/A5_1.c
+++ b/a51/A5_1.c
@@ -74,9 +74,9 @@ void shiftreg(uint8_t* d){
 	d[2] = (d[2]<<1) | c2;
 } 
 
-	uint8_t parity3_lut[] PROGMEM = {0, 1, 1, 0,
+const uint8_t parity3_lut[] PROGMEM = {0, 1, 1, 0,
 		                             1, 0, 0, 1}; 	
-	uint8_t clock_lut[] PROGMEM =  {0x7, 0x6, 0x5, 0x3,
+const uint8_t clock_lut[] PROGMEM =  {0x7, 0x6, 0x5, 0x3,
 		                            0x3, 0x5, 0x6, 0x7}; 
 		                            
 uint8_t a5_1_clock_core(a5_1_ctx_t *c, uint8_t clockoverride){
diff --git a/A5_1.h b/a51/A5_1.h
similarity index 100%
rename from A5_1.h
rename to a51/A5_1.h
diff --git a/mkfiles/a5_1.mk b/mkfiles/a5_1.mk
index 6055e98..2f1806f 100644
--- a/mkfiles/a5_1.mk
+++ b/mkfiles/a5_1.mk
@@ -1,7 +1,7 @@
-# Makefile for ARCFOUR (RC4 compatible)
+# Makefile for A5/1 (from GSM)
 ALGO_NAME := A51
 
-# comment out the following line for removement of ARCFOUR from the build process
+# comment out the following line for removement of A5/1 from the build process
 STREAM_CIPHERS += $(ALGO_NAME)
 
 $(ALGO_NAME)_OBJ      := A5_1.o