diff --git a/src/crypto.c b/src/crypto.c
index 9fc4dcc..4795e3d 100644
--- a/src/crypto.c
+++ b/src/crypto.c
@@ -209,7 +209,12 @@ unsigned char *hex_decode(const char *orig, size_t *sz) {
     }
 
     char *buf = malloc(sizeof(char) * buf_sz);
-    strcpy(buf, orig);
+    if (strlen(orig) % 2 != 0) {
+        strcpy(buf + 1, orig);
+        buf[0] = '0';
+    } else {
+        strcpy(buf, orig);
+    }
     buf[buf_sz - 1] = '\0';
 
     *sz = buf_sz / 2;
diff --git a/tests/tests.c b/tests/tests.c
index e88a1f9..142b87a 100644
--- a/tests/tests.c
+++ b/tests/tests.c
@@ -335,6 +335,16 @@ void test_crypto() {
         assert(s[i] == h[i]);
     }
     free(s);
+
+    // Odd number of characters
+    s = hex_decode("f00f5", &s_sz);
+    unsigned char h2[4] = {
+            0x0F, 0x00, 0xF5
+    };
+    for (size_t i = 0; i < 3; ++i) {
+        assert(s[i] == h2[i]);
+    }
+    free(s);
 }
 
 #if defined(__APPLE__) || defined(__MACH__)