diff --git a/c/secret-handshake/GNUmakefile b/c/secret-handshake/GNUmakefile
new file mode 100644
index 0000000..ec085d0
--- /dev/null
+++ b/c/secret-handshake/GNUmakefile
@@ -0,0 +1,51 @@
+# The original 'makefile' has a flaw:
+# 1) it overrides CFLAGS
+# 2) it does not pass extra "FLAGS" to $(CC) that could come from environment
+#
+# It means :
+# - we need to edit 'makefile' for different builds (DEBUG, etc...), which is
+#   not practical at all.
+# - Also, it does not allow to run all tests without editing the test source
+#   code.
+#
+# To use this makefile (GNU make only):
+#   "make": build with all predefined tests (without editing test source code)
+#   "make debugall": build with all predefined tests and debug code
+#   "make mem": perform memcheck with all tests enabled
+#   "make unit": build standalone (unit) test
+#   "make debug": build standalone test with debugging code
+#
+# Original 'makefile' targets can be used (test, memcheck, clean, ...)
+
+.PHONY: default all mem unit debug std debugtest
+
+default: all
+
+# default is to build with all predefined tests
+BUILD := teststall
+
+include makefile
+
+all: CFLAGS+=-DTESTALL
+all: clean test
+
+debugall: CFLAGS+=-DDEBUG
+debugall: all
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+mem: CFLAGS+=-DTESTALL
+mem: clean memcheck
+
+unit: CFLAGS+=-DUNIT_TEST
+unit: clean std
+
+debug: CFLAGS+=-DUNIT_TEST -DDEBUG
+debug: clean std
+
+debugtest: CFLAGS+=-DDEBUG
+debugtest: test
+
+std: src/*.c src/*.h
+	$(CC) $(CFLAGS) src/*.c -o test.out
diff --git a/c/secret-handshake/README.md b/c/secret-handshake/README.md
new file mode 100644
index 0000000..4c992fd
--- /dev/null
+++ b/c/secret-handshake/README.md
@@ -0,0 +1,67 @@
+# Secret Handshake
+
+> There are 10 types of people in the world: Those who understand
+> binary, and those who don't.
+
+You and your fellow cohort of those in the "know" when it comes to
+binary decide to come up with a secret "handshake".
+
+```text
+1 = wink
+10 = double blink
+100 = close your eyes
+1000 = jump
+
+
+10000 = Reverse the order of the operations in the secret handshake.
+```
+
+Given a decimal number, convert it to the appropriate sequence of events for a secret handshake.
+
+Here's a couple of examples:
+
+Given the input 3, the function would return the array
+["wink", "double blink"] because 3 is 11 in binary.
+
+Given the input 19, the function would return the array
+["double blink", "wink"] because 19 is 10011 in binary.
+Notice that the addition of 16 (10000 in binary)
+has caused the array to be reversed.
+
+## Getting Started
+
+Make sure you have read the "Guides" section of the
+[C track][c-track] on the Exercism site. This covers
+the basic information on setting up the development environment expected
+by the exercises.
+
+## Passing the Tests
+
+Get the first test compiling, linking and passing by following the [three
+rules of test-driven development][3-tdd-rules].
+
+The included makefile can be used to create and run the tests using the `test`
+task.
+
+    make test
+
+Create just the functions you need to satisfy any compiler errors and get the
+test to fail. Then write just enough code to get the test to pass. Once you've
+done that, move onto the next test.
+
+As you progress through the tests, take the time to refactor your
+implementation for readability and expressiveness and then go on to the next
+test.
+
+Try to use standard C99 facilities in preference to writing your own
+low-level algorithms or facilities by hand.
+
+## Source
+
+Bert, in Mary Poppins [http://www.imdb.com/title/tt0058331/quotes/qt0437047](http://www.imdb.com/title/tt0058331/quotes/qt0437047)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[c-track]: https://exercism.io/my/tracks/c
+[3-tdd-rules]: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd
diff --git a/c/secret-handshake/makefile b/c/secret-handshake/makefile
new file mode 100644
index 0000000..f34535a
--- /dev/null
+++ b/c/secret-handshake/makefile
@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: test/*.c src/*.c src/*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) src/*.c test/vendor/unity.c test/*.c -o tests.out $(LIBS)
diff --git a/c/secret-handshake/src/secret_handshake.c b/c/secret-handshake/src/secret_handshake.c
new file mode 100644
index 0000000..8bdd7f6
--- /dev/null
+++ b/c/secret-handshake/src/secret_handshake.c
@@ -0,0 +1,38 @@
+#include <malloc.h>
+#include "secret_handshake.h"
+
+static const char *C[] = { "wink", "double blink", "close your eyes", "jump" };
+
+const char **commands(size_t n)
+{
+    int i=0, c=0, s=1, e=4;
+    const char **r=calloc(4, sizeof(char *));
+
+    if (n & 020) i=3, s=-1, e=-1;                 /* reverse loop params */
+
+    for (; i!=e; i+=s)
+        if (n & (1<<i))
+            r[c++]=*(C+i);
+    return r;
+}
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg=1;
+    int i;
+    const char **res;
+    for (; arg<ac-1; ++arg, ++arg) {
+        i=atoi(av[arg]);
+        res=commands(i);
+        printf("handshake(%d)=\n", i);
+        for (i=0; res[i]; ++i)
+            printf("[%s] ", res[i]);
+        putchar('\n');
+        free(res);
+    }
+}
+#endif
diff --git a/c/secret-handshake/src/secret_handshake.h b/c/secret-handshake/src/secret_handshake.h
new file mode 100644
index 0000000..4cbff25
--- /dev/null
+++ b/c/secret-handshake/src/secret_handshake.h
@@ -0,0 +1,20 @@
+#ifndef SECRET_HANDSHAKE_H
+#define SECRET_HANDSHAKE_H
+
+#include <stddef.h>
+
+const char **commands(size_t number);
+
+/* See GNUmakefile below for explanation
+ * https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+#ifdef  TESTALL
+#undef  TEST_IGNORE
+#define TEST_IGNORE() {}
+#endif
+
+#endif