diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..b44a9ab
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,9 @@
+all: speck-test
+
+speck-test: speck.c speck.h
+	$(CC) -O2 -DTEST -o $@ speck.c
+
+clean:
+	rm -f speck-test
+
+.PHONY: all clean
\ No newline at end of file
diff --git a/speck.c b/speck.c
new file mode 100644
index 0000000..0acd7e4
--- /dev/null
+++ b/speck.c
@@ -0,0 +1,109 @@
+/*
+Copyright (c) 2016, Moritz Bitsch
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+#include "speck.h"
+
+#define ROR(x, r) ((x >> r) | (x << ((sizeof(SPECK_TYPE) * 8) - r)))
+#define ROL(x, r) ((x << r) | (x >> ((sizeof(SPECK_TYPE) * 8) - r)))
+
+#ifdef SPECK_32_64
+#define R(x, y, k) (x = ROR(x, 7), x += y, x ^= k, y = ROL(y, 2), y ^= x)
+#define RR(x, y, k) (y ^= x, y = ROR(y, 2), x ^= k, x -= y, x = ROL(x, 7))
+#else
+#define R(x, y, k) (x = ROR(x, 8), x += y, x ^= k, y = ROL(y, 3), y ^= x)
+#define RR(x, y, k) (y ^= x, y = ROR(y, 3), x ^= k, x -= y, x = ROL(x, 8))
+#endif
+
+void speck_expand(SPECK_TYPE const K[static 4], SPECK_TYPE S[static SPECK_ROUNDS])
+{
+  SPECK_TYPE i, b = K[0];
+  SPECK_TYPE a[SPECK_KEY_LEN - 1];
+
+  for (i = 0; i < (SPECK_KEY_LEN - 1); i++)
+  {
+    a[i] = K[i + 1];
+  }
+  S[0] = b;  
+  for (i = 0; i < SPECK_ROUNDS - 1; i++) {
+    R(a[i % (SPECK_KEY_LEN - 1)], b, i);
+    S[i + 1] = b;
+  }
+}
+
+void speck_encrypt(SPECK_TYPE const pt[static 2], SPECK_TYPE ct[static 2], SPECK_TYPE const K[static SPECK_ROUNDS])
+{
+  SPECK_TYPE i;
+  ct[0]=pt[0]; ct[1]=pt[1];
+
+  for(i = 0; i < SPECK_ROUNDS; i++){
+    R(ct[1], ct[0], K[i]);
+  }
+}
+
+void speck_decrypt(SPECK_TYPE const ct[static 2], SPECK_TYPE pt[static 2], SPECK_TYPE const K[static SPECK_ROUNDS])
+{
+  SPECK_TYPE i;
+  pt[0]=ct[0]; pt[1]=ct[1];
+
+  for(i = 0; i < SPECK_ROUNDS; i++){
+    RR(pt[1], pt[0], K[(SPECK_ROUNDS - 1) - i]);
+  }
+}
+
+#ifdef TEST
+
+#include <string.h>
+#include <stdio.h>
+
+int main(int argc, char** argv)
+{
+#ifdef SPECK_32_64
+  uint16_t key[4] = {0x0100, 0x0908, 0x1110, 0x1918};
+  uint16_t plain[2] = {0x694c, 0x6574};
+  uint16_t enc[2] = {0x42f2, 0xa868};
+#endif
+
+#ifdef SPECK_64_128
+  uint32_t key[4] = {0x03020100, 0x0b0a0908, 0x13121110, 0x1b1a1918};
+  uint32_t plain[2] = {0x7475432d, 0x3b726574};
+  uint32_t enc[2] = {0x454e028b, 0x8c6fa548};
+#endif
+
+#ifdef SPECK_128_256
+  uint64_t key[4] = {0x0706050403020100, 0x0f0e0d0c0b0a0908, 0x1716151413121110, 0x1f1e1d1c1b1a1918};
+  uint64_t plain[2] = {0x202e72656e6f6f70, 0x65736f6874206e49};
+  uint64_t enc[2] = {0x4eeeb48d9c188f43, 0x4109010405c0f53e};
+#endif
+
+  SPECK_TYPE buffer[2] = {0};
+  SPECK_TYPE exp[SPECK_ROUNDS];
+
+  speck_expand(key, exp);
+
+  speck_encrypt(plain, buffer, exp);
+  if (memcmp(buffer, enc, sizeof(enc))) {
+    printf("encryption failed\n");
+    return 1;
+  }
+  speck_decrypt(enc, buffer, exp);
+  if (memcmp(buffer, plain, sizeof(enc))) {
+    printf("decryption failed\n");
+    return 1;
+  }
+  printf("OK\n");
+  return 0;
+}
+
+#endif
\ No newline at end of file
diff --git a/speck.h b/speck.h
new file mode 100644
index 0000000..9e64592
--- /dev/null
+++ b/speck.h
@@ -0,0 +1,56 @@
+/*
+Copyright (c) 2016, Moritz Bitsch
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+#ifndef SPECK_H
+#define SPECK_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+
+/*
+ * define speck type to use (one of SPECK_32_64, SPECK_64_128, SPECK_128_256)
+ */
+#define SPECK_32_64
+
+#ifdef SPECK_32_64
+#define SPECK_TYPE uint16_t
+#define SPECK_ROUNDS 22
+#define SPECK_KEY_LEN 4
+#endif
+
+#ifdef SPECK_64_128
+#define SPECK_TYPE uint32_t
+#define SPECK_ROUNDS 27
+#define SPECK_KEY_LEN 4
+#endif
+
+#ifdef SPECK_128_256
+#define SPECK_TYPE uint64_t
+#define SPECK_ROUNDS 34
+#define SPECK_KEY_LEN 4
+#endif
+
+void speck_expand(SPECK_TYPE const K[static 4], SPECK_TYPE S[static SPECK_ROUNDS]);
+void speck_encrypt(SPECK_TYPE const pt[static 2], SPECK_TYPE ct[static 2], SPECK_TYPE const K[static SPECK_ROUNDS]);
+void speck_decrypt(SPECK_TYPE const ct[static 2], SPECK_TYPE pt[static 2], SPECK_TYPE const K[static SPECK_ROUNDS]);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
\ No newline at end of file