diff --git a/Makefile b/Makefile
index 80db10d..1c93132 100644
--- a/Makefile
+++ b/Makefile
@@ -57,6 +57,9 @@ test/xmssmt: test/xmss.c $(SOURCES) $(OBJS) $(HEADERS)
 test/speed: test/speed.c $(SOURCES_FAST) $(OBJS) $(HEADERS_FAST)
 	$(CC) -DXMSSMT -DXMSS_VARIANT=\"XMSSMT-SHA2_20/2_256\" $(CFLAGS) -o $@ $(SOURCES_FAST) $< $(LDLIBS)
 
+test/vectors: test/vectors.c $(SOURCES) $(OBJS) $(HEADERS)
+	$(CC) -DXMSSMT $(CFLAGS) -o $@ $(SOURCES) $< $(LDLIBS)
+
 test/%: test/%.c $(SOURCES) $(OBJS) $(HEADERS)
 	$(CC) $(CFLAGS) -o $@ $(SOURCES) $< $(LDLIBS)
 
diff --git a/test/vectors.c b/test/vectors.c
new file mode 100644
index 0000000..7573bca
--- /dev/null
+++ b/test/vectors.c
@@ -0,0 +1,126 @@
+/* 
+ * Generate intermediate test vectors useful to test implementations.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "../wots.h"
+#include "../randombytes.h"
+#include "../params.h"
+#include "../fips202.h"
+#include "../xmss_commons.h"
+#include "../xmss_core.h"
+
+void print_hex(unsigned char *buf, int len) {
+    for (int i = 0; i < len; i++) {
+        printf("%x%x", buf[i] / 16, buf[i] & 15);
+    }
+}
+
+void print_hash(unsigned char *buf, int len) {
+    unsigned char tmp[10];
+    shake128(tmp, 10, buf, len);
+    print_hex(tmp, 10);
+}
+
+int vectors_xmss(uint32_t oid, int mt) {
+    xmss_params params;
+
+    if (mt) {
+        xmssmt_parse_oid(&params, oid);
+    } else {
+        xmss_parse_oid(&params, oid);
+    }
+
+    unsigned char seed[params.n * 3];
+    unsigned char pk[params.pk_bytes];
+    unsigned char sk[params.sk_bytes];
+    unsigned char msg[1] = {37};
+    unsigned char sm[params.sig_bytes + 1];
+    unsigned long long smlen = 0;
+
+    for (int i = 0; i < 3*params.n; i++) {
+        seed[i] = i;
+    }
+
+    xmssmt_core_keypair2(&params, pk, sk, seed);
+
+    ull_to_bytes(sk, params.index_bytes, 1 << (params.full_height - 1));
+
+    if (mt) {
+        xmssmt_core_sign(&params, sk, sm, &smlen, msg, 1);
+    } else {
+        xmss_core_sign(&params, sk, sm, &smlen, msg, 1);
+    }
+
+    if (mt) {
+        printf("XMSSMT ");
+    } else {
+        printf("XMSS ");
+    }
+    printf("%d ", oid);
+    print_hash(pk, params.pk_bytes);
+    printf(" ");
+    print_hash(sm, params.sig_bytes);
+    printf("\n");
+}
+
+int vectors_wots(uint32_t oid) {
+    xmss_params params;
+
+    xmss_parse_oid(&params, oid);
+
+    unsigned char sk_seed[params.n];
+    unsigned char pub_seed[params.n];
+
+    unsigned char pk[params.wots_sig_bytes];
+    unsigned char leaf[params.n];
+
+    unsigned char sig[params.wots_sig_bytes];
+    unsigned char m[params.n];
+    uint32_t addr[8] = {0};
+    uint32_t addr2[8] = {0};
+
+    for (int i = 0; i < 8; i++) {
+        addr[i] = 500000000*i;
+        addr2[i] = 400000000*i;
+    }
+
+    for (int i = 0; i < params.n; i++) {
+        m[i] = 3*i;
+        pub_seed[i] = 2*i;
+        sk_seed[i] = i;
+    }
+
+    wots_pkgen(&params, pk, sk_seed, pub_seed, addr);
+    wots_sign(&params, sig, m, sk_seed, pub_seed, addr);
+
+    printf("WOTS+ %d ", oid);
+    print_hash(pk, params.wots_sig_bytes);
+    printf(" ");
+    print_hash(sig, params.wots_sig_bytes);
+    printf(" ");
+
+    // Note that this garbles pk
+    gen_leaf_wots(&params, leaf, sk_seed, pub_seed, addr, addr2);
+    print_hash(leaf, params.n);
+
+    printf("\n");
+
+    return 0;
+}
+
+int main() {
+    for (uint32_t oid = 1; oid <= 0x15; oid += 3) {
+        vectors_wots(oid);
+    }
+    for (uint32_t oid = 2; oid <= 56; oid += 8) {
+        vectors_xmss(oid, 1);
+    }
+    for (uint32_t oid = 1; oid <= 0x15; oid += 3) {
+        vectors_xmss(oid, 0);
+    }
+}
+
diff --git a/xmss_core.c b/xmss_core.c
index 6f159dc..a9a07bf 100644
--- a/xmss_core.c
+++ b/xmss_core.c
@@ -125,6 +125,41 @@ int xmss_core_sign(const xmss_params *params,
     return xmssmt_core_sign(params, sk, sm, smlen, m, mlen);
 }
 
+/*
+ * Derives a XMSSMT key pair for a given parameter set.
+ * Seed must be 3*n long.
+ * Format sk: [(ceil(h/8) bit) index || SK_SEED || SK_PRF || root || PUB_SEED]
+ * Format pk: [root || PUB_SEED] omitting algorithm OID.
+ */
+int xmssmt_core_keypair2(const xmss_params *params,
+                        unsigned char *pk, unsigned char *sk,
+                        unsigned char *seed)
+{
+    /* We do not need the auth path in key generation, but it simplifies the
+       code to have just one treehash routine that computes both root and path
+       in one function. */
+    unsigned char auth_path[params->tree_height * params->n];
+    uint32_t top_tree_addr[8] = {0};
+    set_layer_addr(top_tree_addr, params->d - 1);
+
+    /* Initialize index to 0. */
+    memset(sk, 0, params->index_bytes);
+    sk += params->index_bytes;
+
+    /* Initialize SK_SEED and SK_PRF. */
+    memcpy(sk, seed, 2 * params->n);
+
+    /* Initialize PUB_SEED. */
+    memcpy(sk + 3 * params->n, seed + 2 * params->n,  params->n);
+    memcpy(pk + params->n, sk + 3*params->n, params->n);
+
+    /* Compute root node of the top-most subtree. */
+    treehash(params, pk, auth_path, sk, pk + params->n, 0, top_tree_addr);
+    memcpy(sk + 2*params->n, pk, params->n);
+
+    return 0;
+}
+
 /*
  * Generates a XMSSMT key pair for a given parameter set.
  * Format sk: [(ceil(h/8) bit) index || SK_SEED || SK_PRF || root || PUB_SEED]
diff --git a/xmss_core.h b/xmss_core.h
index 52e9cfb..b3a674c 100644
--- a/xmss_core.h
+++ b/xmss_core.h
@@ -46,6 +46,16 @@ int xmss_core_sign_open(const xmss_params *params,
 int xmssmt_core_keypair(const xmss_params *params,
                         unsigned char *pk, unsigned char *sk);
 
+/*
+ * Derives a XMSSMT key pair for a given parameter set.
+ * Seed must be 3*n long.
+ * Format sk: [(ceil(h/8) bit) index || SK_SEED || SK_PRF || root || PUB_SEED]
+ * Format pk: [root || PUB_SEED] omitting algorithm OID.
+ */
+int xmssmt_core_keypair2(const xmss_params *params,
+                        unsigned char *pk, unsigned char *sk,
+                        unsigned char *seed);
+
 /**
  * Signs a message. Returns an array containing the signature followed by the
  * message and an updated secret key.