diff --git a/rand.c b/rand.c
index 7251826c89..4b921cabb3 100644
--- a/rand.c
+++ b/rand.c
@@ -35,10 +35,9 @@ void init_rand(void)
 
 int finalize_rand(void)
 {
-    int err = fclose(f);
-    f = NULL;
-
-    return err;
+	int err = fclose(f);
+	f = NULL;
+	return err;
 }
 
 uint32_t random32(void)
@@ -50,8 +49,27 @@ uint32_t random32(void)
 	return r;
 }
 
+uint32_t random_uniform(uint32_t n)
+{
+	uint32_t x, max = 0xFFFFFFFF - (0xFFFFFFFF % n);
+	while ((x = random32()) >= max);
+	return x / (max / n);
+}
+
 void random_buffer(uint8_t *buf, size_t len)
 {
 	size_t len_read = fread(buf, 1, len, f);
 	assert(len_read == len);
 }
+
+void random_permute(char *str, size_t len)
+{
+	int i, j;
+	char t;
+	for (i = len - 1; i >= 1; i--) {
+		j = random_uniform(i + 1);
+		t = str[j];
+		str[j] = str[i];
+		str[i] = t;
+	}
+}
diff --git a/rand.h b/rand.h
index 2c78939630..8d81608872 100644
--- a/rand.h
+++ b/rand.h
@@ -24,12 +24,14 @@
 #ifndef __RAND_H__
 #define __RAND_H__
 
-#include <stdlib.h>
 #include <stdint.h>
+#include <stdlib.h>
 
 void init_rand(void);
 int finalize_rand(void);
 uint32_t random32(void);
+uint32_t random_uniform(uint32_t n);
 void random_buffer(uint8_t *buf, size_t len);
+void random_permute(char *buf, size_t len);
 
 #endif