diff --git a/builtins/array.c b/builtins/array.c
index 1b92863..69d5cff 100644
--- a/builtins/array.c
+++ b/builtins/array.c
@@ -426,7 +426,7 @@ public uint32_t Array$hash(const array_t *arr, const TypeInfo *type)
         for (int64_t i = 0; i < arr->length; i++) {
             if (p >= end) {
                 uint32_t chunk_hash;
-                halfsiphash(&hash_batch, sizeof(hash_batch), TOMO_HASH_VECTOR, (uint8_t*)&chunk_hash, sizeof(chunk_hash));
+                halfsiphash(&hash_batch, sizeof(hash_batch), TOMO_HASH_KEY, (uint8_t*)&chunk_hash, sizeof(chunk_hash));
                 p = hash_batch;
                 *(uint32_t*)p = chunk_hash;
                 p += sizeof(uint32_t);
@@ -434,7 +434,7 @@ public uint32_t Array$hash(const array_t *arr, const TypeInfo *type)
             memcpy((p += item_size), arr->data + i*arr->stride, item_size);
         }
         uint32_t hash;
-        halfsiphash(&hash_batch, ((int64_t)p) - ((int64_t)hash_batch), TOMO_HASH_VECTOR, (uint8_t*)&hash, sizeof(hash));
+        halfsiphash(&hash_batch, ((int64_t)p) - ((int64_t)hash_batch), TOMO_HASH_KEY, (uint8_t*)&hash, sizeof(hash));
         return hash;
     } else {
         uint32_t hash_batch[16] = {(uint32_t)arr->length};
@@ -442,14 +442,14 @@ public uint32_t Array$hash(const array_t *arr, const TypeInfo *type)
         for (int64_t i = 0; i < arr->length; i++) {
             if (p >= end) {
                 uint64_t chunk_hash;
-                halfsiphash(&hash_batch, sizeof(hash_batch), TOMO_HASH_VECTOR, (uint8_t*)&chunk_hash, sizeof(chunk_hash));
+                halfsiphash(&hash_batch, sizeof(hash_batch), TOMO_HASH_KEY, (uint8_t*)&chunk_hash, sizeof(chunk_hash));
                 p = hash_batch;
                 *(p++) = chunk_hash;
             }
             *(p++) = generic_hash(arr->data + i*arr->stride, item);
         }
         uint32_t hash;
-        halfsiphash(&hash_batch, ((int64_t)p) - ((int64_t)hash_batch), TOMO_HASH_VECTOR, (uint8_t*)&hash, sizeof(hash));
+        halfsiphash(&hash_batch, ((int64_t)p) - ((int64_t)hash_batch), TOMO_HASH_KEY, (uint8_t*)&hash, sizeof(hash));
         return hash;
     }
 }
diff --git a/builtins/c_string.c b/builtins/c_string.c
index f74d6da..3b258aa 100644
--- a/builtins/c_string.c
+++ b/builtins/c_string.c
@@ -38,7 +38,7 @@ public uint32_t CString$hash(const char **c_str)
     if (!*c_str) return 0;
 
     uint32_t hash;
-    halfsiphash(*c_str, strlen(*c_str), TOMO_HASH_VECTOR, (uint8_t*)&hash, sizeof(hash));
+    halfsiphash(*c_str, strlen(*c_str), TOMO_HASH_KEY, (uint8_t*)&hash, sizeof(hash));
     return hash;
 }
 
diff --git a/builtins/functions.c b/builtins/functions.c
index 7ece75e..8916f93 100644
--- a/builtins/functions.c
+++ b/builtins/functions.c
@@ -7,6 +7,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <sys/param.h>
+#include <sys/random.h>
 #include <uninorm.h>
 #include <unistd.h>
 
@@ -22,14 +23,17 @@
 #include "types.h"
 #include "util.h"
 
-public const char *TOMO_HASH_VECTOR = "tomo hash vector ---------------------------------------------";
+public uint8_t TOMO_HASH_KEY[8] = {0};
 
 public void tomo_init(void)
 {
    GC_INIT();
    USE_COLOR = getenv("COLOR") ? strcmp(getenv("COLOR"), "1") == 0 : isatty(STDOUT_FILENO);
-   srand(arc4random_uniform(UINT32_MAX));
-   srand48(arc4random_uniform(UINT32_MAX));
+   getrandom(TOMO_HASH_KEY, sizeof(TOMO_HASH_KEY), 0);
+   unsigned int seed;
+   getrandom(&seed, sizeof(seed), 0);
+   srand(seed);
+   srand48(seed);
 }
 
 public void fail(CORD fmt, ...)
@@ -98,7 +102,7 @@ public uint32_t generic_hash(const void *obj, const TypeInfo *type)
     default: {
       hash_data:;
         uint32_t hash;
-        halfsiphash((void*)obj, type->size, TOMO_HASH_VECTOR, (uint8_t*)&hash, sizeof(hash));
+        halfsiphash((void*)obj, type->size, TOMO_HASH_KEY, (uint8_t*)&hash, sizeof(hash));
         return hash;
     }
     }
diff --git a/builtins/functions.h b/builtins/functions.h
index cf19a12..a62865b 100644
--- a/builtins/functions.h
+++ b/builtins/functions.h
@@ -8,7 +8,7 @@
 
 #include "types.h"
 
-extern const char *TOMO_HASH_VECTOR;
+extern uint8_t TOMO_HASH_KEY[8];
 
 void tomo_init(void);
 
diff --git a/builtins/pointer.c b/builtins/pointer.c
index d71811b..73bd41b 100644
--- a/builtins/pointer.c
+++ b/builtins/pointer.c
@@ -71,7 +71,7 @@ public bool Pointer$equal(const void *x, const void *y, const TypeInfo *type) {
 public uint32_t Pointer$hash(const void *x, const TypeInfo *type) {
     (void)type;
     uint32_t hash;
-    halfsiphash(x, sizeof(void*), TOMO_HASH_VECTOR, (uint8_t*)&hash, sizeof(hash));
+    halfsiphash(x, sizeof(void*), TOMO_HASH_KEY, (uint8_t*)&hash, sizeof(hash));
     return hash;
 }
 
diff --git a/builtins/table.c b/builtins/table.c
index 6b63be8..6afca9c 100644
--- a/builtins/table.c
+++ b/builtins/table.c
@@ -500,7 +500,7 @@ public uint32_t Table$hash(const table_t *t, const TypeInfo *type)
         default_hash,
     };
     uint32_t hash;
-    halfsiphash(&components, sizeof(components), TOMO_HASH_VECTOR, (uint8_t*)&hash, sizeof(hash));
+    halfsiphash(&components, sizeof(components), TOMO_HASH_KEY, (uint8_t*)&hash, sizeof(hash));
     return hash;
 }
 
diff --git a/builtins/text.c b/builtins/text.c
index f39d42e..666d5df 100644
--- a/builtins/text.c
+++ b/builtins/text.c
@@ -123,7 +123,7 @@ public uint32_t Text$hash(const CORD *cord)
     uint8_t *normalized = _normalize(*cord, buf, &norm_len);
 
     uint32_t hash;
-    halfsiphash(normalized, norm_len, TOMO_HASH_VECTOR, (uint8_t*)&hash, sizeof(hash));
+    halfsiphash(normalized, norm_len, TOMO_HASH_KEY, (uint8_t*)&hash, sizeof(hash));
     if (normalized != buf) free(normalized);
     return hash;
 }
diff --git a/enums.c b/enums.c
index 344b5f1..4e63221 100644
--- a/enums.c
+++ b/enums.c
@@ -124,7 +124,7 @@ static CORD compile_hash_method(env_t *env, ast_t *ast)
         return CORD_all("static uint32_t ", full_name, "$hash(const ", full_name, "_t *obj, const TypeInfo *info) {\n"
                         "(void)info;\n"
                         "uint32_t hash;\n"
-                        "halfsiphash(&obj->$tag, sizeof(obj->$tag), TOMO_HASH_VECTOR, (uint8_t*)&hash, sizeof(hash));\n"
+                        "halfsiphash(&obj->$tag, sizeof(obj->$tag), TOMO_HASH_KEY, (uint8_t*)&hash, sizeof(hash));\n"
                         "return hash;"
                         "\n}\n");
     }
@@ -144,7 +144,7 @@ static CORD compile_hash_method(env_t *env, ast_t *ast)
     }
     hash_func = CORD_all(hash_func, "}\n"
                          "uint32_t hash;\n"
-                         "halfsiphash(&hashes, sizeof(hashes), TOMO_HASH_VECTOR, (uint8_t*)&hash, sizeof(hash));\n"
+                         "halfsiphash(&hashes, sizeof(hashes), TOMO_HASH_KEY, (uint8_t*)&hash, sizeof(hash));\n"
                          "return hash;\n}\n");
     return hash_func;
 }
diff --git a/structs.c b/structs.c
index 51f6928..22965b7 100644
--- a/structs.c
+++ b/structs.c
@@ -109,7 +109,7 @@ static CORD compile_hash_method(env_t *env, ast_t *ast)
     }
     hash_func = CORD_all(hash_func, "};\n"
                          "uint32_t hash;\n"
-                         "halfsiphash(&field_hashes, sizeof(field_hashes), TOMO_HASH_VECTOR, (uint8_t*)&hash, sizeof(hash));\n"
+                         "halfsiphash(&field_hashes, sizeof(field_hashes), TOMO_HASH_KEY, (uint8_t*)&hash, sizeof(hash));\n"
                          "return hash;\n}\n");
     return hash_func;
 }