Avoid duplicate program names

Visual Studio and CMake didn't like having targets with the same name,
albeit in different directories.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/programs/cipher/CMakeLists.txt b/programs/cipher/CMakeLists.txt
index cc16849..93e5f31 100644
--- a/programs/cipher/CMakeLists.txt
+++ b/programs/cipher/CMakeLists.txt
@@ -1,5 +1,5 @@
 set(executables
-    aead_demo
+    cipher_aead_demo
 )
 
 foreach(exe IN LISTS executables)
diff --git a/programs/cipher/aead_demo.c b/programs/cipher/cipher_aead_demo.c
similarity index 98%
rename from programs/cipher/aead_demo.c
rename to programs/cipher/cipher_aead_demo.c
index 894225d..4da1bfc 100644
--- a/programs/cipher/aead_demo.c
+++ b/programs/cipher/cipher_aead_demo.c
@@ -66,7 +66,7 @@
 
 /* The real program starts here. */
 
-const char usage[] = "Usage: aead_demo [aes128-gcm|aes256-gcm|aes128-gcm_8|chachapoly]";
+const char usage[] = "Usage: cipher_aead_demo [aes128-gcm|aes256-gcm|aes128-gcm_8|chachapoly]";
 
 /* Dummy data for encryption: IV/nonce, additional data, 2-part message */
 const unsigned char iv1[12] = { 0x00 };