diff --git a/.gitignore b/.gitignore
index 526277f9..b8eb2a13 100644
--- a/.gitignore
+++ b/.gitignore
@@ -114,6 +114,7 @@ test/default/hash3
 test/default/kdf
 test/default/keygen
 test/default/kx
+test/default/metamorphic
 test/default/misuse
 test/default/onetimeauth
 test/default/onetimeauth2
diff --git a/test/default/Makefile.am b/test/default/Makefile.am
index 4e1d79d3..835ad74c 100644
--- a/test/default/Makefile.am
+++ b/test/default/Makefile.am
@@ -37,6 +37,7 @@ EXTRA_DIST = \
 	kdf.exp \
 	keygen.exp \
 	kx.exp \
+	metamorphic.exp \
 	misuse.exp \
 	onetimeauth.exp \
 	onetimeauth2.exp \
@@ -108,6 +109,7 @@ DISTCLEANFILES = \
 	kdf.res \
 	keygen.res \
 	kx.res \
+	metamorphic.res \
 	misuse.res \
 	onetimeauth.res \
 	onetimeauth2.res \
@@ -180,6 +182,7 @@ CLEANFILES = \
 	kdf.final \
 	keygen.final \
 	kx.final \
+	metamorphic.final \
 	misuse.final \
 	onetimeauth.final \
 	onetimeauth2.final \
@@ -247,6 +250,7 @@ CLEANFILES = \
 	kdf.nexe \
 	keygen.nexe \
 	kx.nexe \
+	metamorphic.nexe \
 	misuse.nexe \
 	onetimeauth.nexe \
 	onetimeauth2.nexe \
@@ -326,6 +330,7 @@ TESTS_TARGETS = \
 	kdf \
 	keygen \
 	kx \
+	metamorphic \
 	misuse \
 	onetimeauth \
 	onetimeauth2 \
@@ -470,6 +475,9 @@ keygen_LDADD              = $(TESTS_LDADD)
 kx_SOURCE                 = cmptest.h kx.c
 kx_LDADD                  = $(TESTS_LDADD)
 
+metamorphic_SOURCE        = cmptest.h metamorphic.c
+metamorphic_LDADD         = $(TESTS_LDADD)
+
 misuse_SOURCE             = cmptest.h misuse.c
 misuse_LDADD              = $(TESTS_LDADD)
 
diff --git a/test/default/metamorphic.c b/test/default/metamorphic.c
new file mode 100644
index 00000000..96cf71e0
--- /dev/null
+++ b/test/default/metamorphic.c
@@ -0,0 +1,63 @@
+
+#define TEST_NAME "metamorphic"
+#include "cmptest.h"
+
+#define MAXLEN 512
+#define MAX_ITER 1000
+
+static void
+mm_1(void)
+{
+    crypto_generichash_state st;
+    unsigned char *h, *h2;
+    unsigned char *k;
+    unsigned char *m;
+    size_t         hlen;
+    size_t         klen;
+    size_t         mlen;
+    size_t         l1, l2;
+    int            i;
+
+    for (i = 0; i < MAX_ITER; i++) {
+        mlen = randombytes_uniform(MAXLEN);
+        m = (unsigned char *) sodium_malloc(mlen);
+        klen = randombytes_uniform(crypto_generichash_KEYBYTES_MAX -
+                                   crypto_generichash_KEYBYTES_MIN + 1U)
+            + crypto_generichash_KEYBYTES_MIN;
+        k = (unsigned char *) sodium_malloc(klen);
+        hlen = randombytes_uniform(crypto_generichash_BYTES_MAX -
+                                   crypto_generichash_BYTES_MIN + 1U)
+            + crypto_generichash_BYTES_MIN;
+        h = (unsigned char *) sodium_malloc(hlen);
+        h2 = (unsigned char *) sodium_malloc(hlen);
+
+        randombytes_buf(m, mlen);
+        
+        crypto_generichash_init(&st, k, klen, hlen);
+        l1 = randombytes_uniform(mlen);
+        l2 = randombytes_uniform(mlen - l1);
+        crypto_generichash_update(&st, m, l1);
+        crypto_generichash_update(&st, m + l1, l2);
+        crypto_generichash_update(&st, m + l1 + l2, mlen - l1 - l2);
+        crypto_generichash_final(&st, h, hlen);
+
+        crypto_generichash(h2, hlen, m, mlen, k, klen);
+
+        assert(memcmp(h, h2, hlen) == 0);
+
+        sodium_free(h2);
+        sodium_free(h);
+        sodium_free(k);
+        sodium_free(m);
+    }
+}
+
+int
+main(void)
+{
+    mm_1();
+
+    printf("OK\n");
+
+    return 0;
+}
diff --git a/test/default/metamorphic.exp b/test/default/metamorphic.exp
new file mode 100644
index 00000000..d86bac9d
--- /dev/null
+++ b/test/default/metamorphic.exp
@@ -0,0 +1 @@
+OK