diff --git a/set1/src/fixed-xor.c b/set1/src/fixed-xor.c
new file mode 100644
index 0000000..46368cd
--- /dev/null
+++ b/set1/src/fixed-xor.c
@@ -0,0 +1,38 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/*
+void fixed_xor_stream(uint8_t *key, size_t key_len)
+{
+	//
+}
+*/
+
+void fixed_xor(const uint8_t *data, const size_t data_len,
+               const uint8_t key)
+{
+	uint8_t c;
+	size_t i;
+
+	for (i = 0; i < data_len; ++i) {
+		c = data[i] ^ key;
+		putchar(c);
+	}
+}
+
+int main()
+{
+	uint8_t data[] = "\x1c\x01\x11\x00\x1f\x01\x01\x00\x06\x1a\x02\x4b\x53"
+	                 "\x53\x50\x09\x18\x1c\x00\x00\x00\x00\x00\x00\x00";
+	/* // above array XOR'd by 0x41
+	uint8_t data[] = "\x5d\x40\x50\x41\x5e\x40\x40\x41\x47\x5b\x43\x0a\x12"
+	                 "\x12\x11\x48\x59\x5d\x41\x41\x41\x41\x41\x41\x41";
+	*/
+	uint8_t key = 0x41;
+
+	fixed_xor(data, sizeof(data)-1, key);
+
+	return EXIT_SUCCESS;
+}
+