diff --git a/.gitignore b/.gitignore
index c6c2e9a..69cb3c8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,14 +1,14 @@
 test/test_chacha
 test/test_wots
 test/test_horst
-test/test_xmss
-test/test_xmss_fast
-test/test_xmssmt
-test/test_xmssmt_fast
-test/test_xmss_XMSS*
-test/test_xmss_fast_XMSS*
-test/test_xmssmt_XMSSMT*
-test/test_xmssmt_fast_XMSSMT*
+test/test_xmss_core
+test/test_xmss_core_fast
+test/test_xmssmt_core
+test/test_xmssmt_core_fast
+test/test_xmss_core_XMSS*
+test/test_xmss_core_fast_XMSS*
+test/test_xmssmt_core_XMSSMT*
+test/test_xmssmt_core_fast_XMSSMT*
 test/speed
 test/gen_testvectors
 params_XMSS_*.h
diff --git a/Makefile b/Makefile
index 97af0c3..d307108 100644
--- a/Makefile
+++ b/Makefile
@@ -2,10 +2,10 @@ CC = /usr/bin/gcc
 CFLAGS = -Wall -g -O3 -Wextra
 
 all: test/test_wots \
-test/test_xmss_XMSS_SHA2-256_W16_H10 \
-test/test_xmss_fast_XMSS_SHA2-256_W16_H10 \
-test/test_xmssmt_fast_XMSSMT_SHA2-256_W16_H20_D4 \
-test/test_xmssmt_XMSSMT_SHA2-256_W16_H20_D4
+test/test_xmss_core_XMSS_SHA2-256_W16_H10 \
+test/test_xmss_core_fast_XMSS_SHA2-256_W16_H10 \
+test/test_xmssmt_core_fast_XMSSMT_SHA2-256_W16_H20_D4 \
+test/test_xmssmt_core_XMSSMT_SHA2-256_W16_H20_D4 \
 
 .PHONY: clean
 .PRECIOUS: params_%.h
@@ -17,29 +17,29 @@ test/test_wots: params_XMSS_SHA2-256_W16_H10.h hash.c fips202.c hash_address.c r
 	ln -sf params_XMSS_SHA2-256_W16_H10.h params.h
 	$(CC) $(CFLAGS) hash.c fips202.c hash_address.c randombytes.c wots.c xmss_commons.c test/test_wots.c -o $@ -lcrypto -lm
 
-test/test_xmss_XMSS_%: params_XMSS_%.h hash.c fips202.c hash_address.c randombytes.c wots.c xmss.c xmss_commons.c test/test_xmss.c hash.h fips202.h hash_address.h randombytes.h wots.h xmss.h xmss_commons.h
-	ln -sf params_XMSS_$(patsubst test/test_xmss_XMSS_%,%,$@).h params.h
-	$(CC) $(CFLAGS) hash.c fips202.c hash_address.c randombytes.c wots.c xmss.c xmss_commons.c test/test_xmss.c -o $@ -lcrypto -lm
+test/test_xmss_core_XMSS_%: params_XMSS_%.h hash.c fips202.c hash_address.c randombytes.c wots.c xmss_core.c xmss_commons.c test/test_xmss_core.c hash.h fips202.h hash_address.h randombytes.h wots.h xmss_core.h xmss_commons.h
+	ln -sf params_XMSS_$(patsubst test/test_xmss_core_XMSS_%,%,$@).h params.h
+	$(CC) $(CFLAGS) hash.c fips202.c hash_address.c randombytes.c wots.c xmss_core.c xmss_commons.c test/test_xmss_core.c -o $@ -lcrypto -lm
 
-test/test_xmss_fast_XMSS_%: params_XMSS_%.h hash.c fips202.c hash_address.c randombytes.c wots.c xmss_fast.c xmss_commons.c test/test_xmss_fast.c hash.h fips202.h hash_address.h randombytes.h wots.h xmss_fast.h xmss_commons.h
-	ln -sf params_XMSS_$(patsubst test/test_xmss_fast_XMSS_%,%,$@).h params.h
-	$(CC) $(CFLAGS) hash.c fips202.c hash_address.c randombytes.c wots.c xmss_fast.c xmss_commons.c test/test_xmss_fast.c -o $@ -lcrypto -lm
+test/test_xmss_core_fast_XMSS_%: params_XMSS_%.h hash.c fips202.c hash_address.c randombytes.c wots.c xmss_core_fast.c xmss_commons.c test/test_xmss_core_fast.c hash.h fips202.h hash_address.h randombytes.h wots.h xmss_core_fast.h xmss_commons.h
+	ln -sf params_XMSS_$(patsubst test/test_xmss_core_fast_XMSS_%,%,$@).h params.h
+	$(CC) $(CFLAGS) hash.c fips202.c hash_address.c randombytes.c wots.c xmss_core_fast.c xmss_commons.c test/test_xmss_core_fast.c -o $@ -lcrypto -lm
 
-test/test_xmssmt_XMSSMT_%: params_XMSSMT_%.h hash.c fips202.c hash_address.c randombytes.c wots.c xmss.c xmss_commons.c test/test_xmssmt.c hash.h fips202.h hash_address.h randombytes.h wots.h xmss.h xmss_commons.h
-	ln -sf params_XMSSMT_$(patsubst test/test_xmssmt_XMSSMT_%,%,$@).h params.h
-	$(CC) $(CFLAGS) hash.c fips202.c hash_address.c randombytes.c wots.c xmss.c xmss_commons.c test/test_xmssmt.c -o $@ -lcrypto -lm
+test/test_xmssmt_core_XMSSMT_%: params_XMSSMT_%.h hash.c fips202.c hash_address.c randombytes.c wots.c xmss_core.c xmss_commons.c test/test_xmssmt_core.c hash.h fips202.h hash_address.h randombytes.h wots.h xmss_core.h xmss_commons.h
+	ln -sf params_XMSSMT_$(patsubst test/test_xmssmt_core_XMSSMT_%,%,$@).h params.h
+	$(CC) $(CFLAGS) hash.c fips202.c hash_address.c randombytes.c wots.c xmss_core.c xmss_commons.c test/test_xmssmt_core.c -o $@ -lcrypto -lm
 
-test/test_xmssmt_fast_XMSSMT_%: params_XMSSMT_%.h hash.c fips202.c hash_address.c randombytes.c wots.c xmss_fast.c xmss_commons.c test/test_xmssmt_fast.c hash.h fips202.h hash_address.h randombytes.h wots.h xmss_fast.h xmss_commons.h
-	ln -sf params_XMSSMT_$(patsubst test/test_xmssmt_fast_XMSSMT_%,%,$@).h params.h
-	$(CC) $(CFLAGS) hash.c fips202.c hash_address.c randombytes.c wots.c xmss_fast.c xmss_commons.c test/test_xmssmt_fast.c -o $@ -lcrypto -lm
+test/test_xmssmt_core_fast_XMSSMT_%: params_XMSSMT_%.h hash.c fips202.c hash_address.c randombytes.c wots.c xmss_core_fast.c xmss_commons.c test/test_xmssmt_core_fast.c hash.h fips202.h hash_address.h randombytes.h wots.h xmss_core_fast.h xmss_commons.h
+	ln -sf params_XMSSMT_$(patsubst test/test_xmssmt_core_fast_XMSSMT_%,%,$@).h params.h
+	$(CC) $(CFLAGS) hash.c fips202.c hash_address.c randombytes.c wots.c xmss_core_fast.c xmss_commons.c test/test_xmssmt_core_fast.c -o $@ -lcrypto -lm
 
 clean:
 	-rm *.o *.s
 	-rm test/test_wots
-	-rm test/test_xmss_XMSS*
-	-rm test/test_xmss_fast_XMSS*
-	-rm test/test_xmssmt_XMSS*
-	-rm test/test_xmssmt_fast_XMSS*
+	-rm test/test_xmss_core_XMSS*
+	-rm test/test_xmss_core_fast_XMSS*
+	-rm test/test_xmssmt_core_XMSS*
+	-rm test/test_xmssmt_core_fast_XMSS*
 
 distclean:
 	-rm params.h
diff --git a/test/test_xmss.c b/test/test_xmss_core.c
similarity index 86%
rename from test/test_xmss.c
rename to test/test_xmss_core.c
index bd0a613..5e2cdc7 100644
--- a/test/test_xmss.c
+++ b/test/test_xmss_core.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "../xmss.h"
+#include "../xmss_core.h"
 #include "../params.h"
 #include "../randombytes.h"
 
@@ -26,7 +26,7 @@ int main()
   unsigned char sm[MLEN+signature_length];
 
   printf("keypair\n");
-  xmss_keypair(pk, sk);
+  xmss_core_keypair(pk, sk);
   // check pub_seed in SK
   for (i = 0; i < XMSS_N; i++) {
     if (pk[XMSS_N+i] != sk[4+2*XMSS_N+i]) printf("pk.pub_seed != sk.pub_seed %llu",i);
@@ -41,7 +41,7 @@ int main()
     randombytes(mi, MLEN);
 
     printf("sign\n");
-    xmss_sign(sk, sm, &smlen, mi, MLEN);
+    xmss_core_sign(sk, sm, &smlen, mi, MLEN);
     idx = ((unsigned long)sm[0] << 24) | ((unsigned long)sm[1] << 16) | ((unsigned long)sm[2] << 8) | sm[3];
     printf("\nidx = %lu\n",idx);
 
@@ -55,7 +55,7 @@ int main()
 
     /* Test valid signature */
     printf("verify\n");
-    r = xmss_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmss_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r);
     if (r != 0) errors++;
     r = memcmp(mi,mo,MLEN);
@@ -64,7 +64,7 @@ int main()
 
     /* Test with modified message */
     sm[signature_length+10] ^= 1;
-    r = xmss_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmss_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     if (r == 0) errors++;
     r = memcmp(mi,mo,MLEN);
@@ -75,7 +75,7 @@ int main()
     /* Modified index */
     sm[signature_length+10] ^= 1;
     sm[2] ^= 1;
-    r = xmss_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmss_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     if (r == 0) errors++;
     r = memcmp(mi,mo,MLEN);
@@ -85,7 +85,7 @@ int main()
     /* Modified R */
     sm[2] ^= 1;
     sm[5] ^= 1;
-    r = xmss_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmss_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     if (r == 0) errors++;
     r = memcmp(mi,mo,MLEN);
@@ -95,7 +95,7 @@ int main()
     /* Modified OTS sig */
     sm[5] ^= 1;
     sm[240] ^= 1;
-    r = xmss_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmss_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     if (r == 0) errors++;
     r = memcmp(mi,mo,MLEN);
@@ -105,7 +105,7 @@ int main()
     /* Modified AUTH */
     sm[240] ^= 1;
     sm[signature_length - 10] ^= 1;
-    r = xmss_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmss_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     if (r == 0) errors++;
     r = memcmp(mi,mo,MLEN);
diff --git a/test/test_xmss_fast.c b/test/test_xmss_core_fast.c
similarity index 89%
rename from test/test_xmss_fast.c
rename to test/test_xmss_core_fast.c
index e6cf829..2d7ea1d 100644
--- a/test/test_xmss_fast.c
+++ b/test/test_xmss_core_fast.c
@@ -2,7 +2,7 @@
 #include <string.h>
 #include <stdlib.h>
 
-#include "../xmss_fast.h"
+#include "../xmss_core_fast.h"
 #include "../params.h"
 #include "../randombytes.h"
 
@@ -55,7 +55,7 @@ int main()
 
   printf("keypair\n");
   t1 = cpucycles();
-  xmss_keypair(pk, sk, state);
+  xmss_core_keypair(pk, sk, state);
   t2 = cpucycles();
   printf("cycles = %llu\n", (t2-t1));
   double sec = (t2-t1)/3500000;
@@ -72,7 +72,7 @@ int main()
 
   for (i = 0; i < SIGNATURES; i++) {
     printf("sign\n");
-    xmss_sign(sk, state, sm, &smlen, mi, MLEN);
+    xmss_core_sign(sk, state, sm, &smlen, mi, MLEN);
     idx = ((unsigned long)sm[0] << 24) | ((unsigned long)sm[1] << 16) | ((unsigned long)sm[2] << 8) | sm[3];
     printf("\nidx = %lu\n",idx);
 
@@ -81,7 +81,7 @@ int main()
 
         /* Test valid signature */
     printf("verify\n");
-    r = xmss_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmss_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r);
     if (r != 0) errors++;
     r = memcmp(mi,mo,MLEN);
@@ -90,7 +90,7 @@ int main()
 
     /* Test with modified message */
     sm[signature_length+10] ^= 1;
-    r = xmss_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmss_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     if (r == 0) errors++;
     r = memcmp(mi,mo,MLEN);
@@ -101,7 +101,7 @@ int main()
     /* Modified index */
     sm[signature_length+10] ^= 1;
     sm[2] ^= 1;
-    r = xmss_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmss_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     if (r == 0) errors++;
     r = memcmp(mi,mo,MLEN);
@@ -111,7 +111,7 @@ int main()
     /* Modified R */
     sm[2] ^= 1;
     sm[5] ^= 1;
-    r = xmss_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmss_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     if (r == 0) errors++;
     r = memcmp(mi,mo,MLEN);
@@ -121,7 +121,7 @@ int main()
     /* Modified OTS sig */
     sm[5] ^= 1;
     sm[240] ^= 1;
-    r = xmss_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmss_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     if (r == 0) errors++;
     r = memcmp(mi,mo,MLEN);
@@ -131,7 +131,7 @@ int main()
     /* Modified AUTH */
     sm[240] ^= 1;
     sm[signature_length - 10] ^= 1;
-    r = xmss_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmss_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     if (r == 0) errors++;
     r = memcmp(mi,mo,MLEN);
diff --git a/test/test_xmssmt.c b/test/test_xmssmt_core.c
similarity index 88%
rename from test/test_xmssmt.c
rename to test/test_xmssmt_core.c
index ef79b4e..642b90a 100644
--- a/test/test_xmssmt.c
+++ b/test/test_xmssmt_core.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "../xmss.h"
+#include "../xmss_core.h"
 #include "../params.h"
 #include "../randombytes.h"
 
@@ -25,7 +25,7 @@ int main()
   unsigned char sm[MLEN+signature_length];
 
   printf("keypair\n");
-  xmssmt_keypair(pk, sk);
+  xmssmt_core_keypair(pk, sk);
   // check pub_seed in SK
   for (i = 0; i < XMSS_N; i++) {
     if (pk[XMSS_N+i] != sk[XMSS_INDEX_LEN+2*XMSS_N+i]) printf("pk.pub_seed != sk.pub_seed %llu",i);
@@ -46,7 +46,7 @@ int main()
     randombytes(mi, MLEN);
 
     printf("sign\n");
-    xmssmt_sign(sk, sm, &smlen, mi, MLEN);
+    xmssmt_core_sign(sk, sm, &smlen, mi, MLEN);
     idx = 0;
     for (j = 0; j < idx_len; j++) {
       idx += ((unsigned long long)sm[j]) << 8*(idx_len - 1 - j);
@@ -62,7 +62,7 @@ int main()
 
     /* Test valid signature */
     printf("verify\n");
-    r = xmssmt_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmssmt_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r);
     r = memcmp(mi,mo,MLEN);
     printf("%d\n", r);
@@ -70,7 +70,7 @@ int main()
 
     /* Test with modified message */
     sm[52] ^= 1;
-    r = xmssmt_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmssmt_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     r = memcmp(mi,mo,MLEN);
     printf("%d\n", (r!=0) - 1);
@@ -80,7 +80,7 @@ int main()
     sm[260] ^= 1;
     sm[52] ^= 1;
     sm[2] ^= 1;
-    r = xmssmt_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmssmt_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     r = memcmp(mi,mo,MLEN);
     printf("%d\n", (r!=0) - 1);
diff --git a/test/test_xmssmt_fast.c b/test/test_xmssmt_core_fast.c
similarity index 91%
rename from test/test_xmssmt_fast.c
rename to test/test_xmssmt_core_fast.c
index 0258a16..4579d05 100644
--- a/test/test_xmssmt_fast.c
+++ b/test/test_xmssmt_core_fast.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "../xmss_fast.h"
+#include "../xmss_core_fast.h"
 #include "../params.h"
 #include "../randombytes.h"
 
@@ -67,7 +67,7 @@ int main()
   randombytes(mi, MLEN);
 
   printf("keypair\n");
-  xmssmt_keypair(pk, sk, states, wots_sigs);
+  xmssmt_core_keypair(pk, sk, states, wots_sigs);
   // check pub_seed in SK
   for (i = 0; i < n; i++) {
     if (pk[n+i] != sk[XMSS_INDEX_LEN+2*n+i]) printf("pk.pub_seed != sk.pub_seed %llu",i);
@@ -87,7 +87,7 @@ int main()
   for (i = 0; i < SIGNATURES; i++) {
     printf("sign\n");
     t1 = cpucycles();
-    xmssmt_sign(sk, states, wots_sigs, sm, &smlen, mi, MLEN);
+    xmssmt_core_sign(sk, states, wots_sigs, sm, &smlen, mi, MLEN);
     t2 = cpucycles();
     printf("signing cycles = %llu\n", (t2-t1));
 
@@ -102,7 +102,7 @@ int main()
     /* Test valid signature */
     printf("verify\n");
     t1 = cpucycles();
-    r = xmssmt_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmssmt_core_sign_open(mo, &mlen, sm, smlen, pk);
     t2 = cpucycles();
     printf("verification cycles = %llu\n", (t2-t1));
     printf("%d\n", r);
@@ -112,7 +112,7 @@ int main()
 
     /* Test with modified message */
     sm[52] ^= 1;
-    r = xmssmt_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmssmt_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     r = memcmp(mi,mo,MLEN);
     printf("%d\n", (r!=0) - 1);
@@ -122,7 +122,7 @@ int main()
     sm[260] ^= 1;
     sm[52] ^= 1;
     sm[2] ^= 1;
-    r = xmssmt_sign_open(mo, &mlen, sm, smlen, pk);
+    r = xmssmt_core_sign_open(mo, &mlen, sm, smlen, pk);
     printf("%d\n", r+1);
     r = memcmp(mi,mo,MLEN);
     printf("%d\n", (r!=0) - 1);
diff --git a/xmss_commons.c b/xmss_commons.c
index 4fb3a97..4993753 100644
--- a/xmss_commons.c
+++ b/xmss_commons.c
@@ -146,7 +146,7 @@ static void validate_authpath(unsigned char *root, const unsigned char *leaf, un
 /**
  * Verifies a given message signature pair under a given public key.
  */
-int xmss_sign_open(unsigned char *m, unsigned long long *mlen, const unsigned char *sm, unsigned long long smlen, const unsigned char *pk)
+int xmss_core_sign_open(unsigned char *m, unsigned long long *mlen, const unsigned char *sm, unsigned long long smlen, const unsigned char *pk)
 {
   unsigned long long i, m_len;
   unsigned long idx=0;
@@ -229,7 +229,7 @@ fail:
 /**
  * Verifies a given message signature pair under a given public key.
  */
-int xmssmt_sign_open(unsigned char *m, unsigned long long *mlen, const unsigned char *sm, unsigned long long smlen, const unsigned char *pk)
+int xmssmt_core_sign_open(unsigned char *m, unsigned long long *mlen, const unsigned char *sm, unsigned long long smlen, const unsigned char *pk)
 {
   uint64_t idx_tree;
   uint32_t idx_leaf;
diff --git a/xmss_commons.h b/xmss_commons.h
index 313962c..a9b5199 100644
--- a/xmss_commons.h
+++ b/xmss_commons.h
@@ -15,6 +15,6 @@ void hexdump(const unsigned char *a, size_t len);
 void gen_leaf_wots(unsigned char *leaf, const unsigned char *sk_seed, const unsigned char *pub_seed, uint32_t ltree_addr[8], uint32_t ots_addr[8]);
 void get_seed(unsigned char *seed, const unsigned char *sk_seed, uint32_t addr[8]);
 void l_tree(unsigned char *leaf, unsigned char *wots_pk, const unsigned char *pub_seed, uint32_t addr[8]);
-int xmss_sign_open(unsigned char *msg, unsigned long long *msglen, const unsigned char *sig_msg, unsigned long long sig_msg_len, const unsigned char *pk);
-int xmssmt_sign_open(unsigned char *msg, unsigned long long *msglen, const unsigned char *sig_msg, unsigned long long sig_msg_len, const unsigned char *pk);
+int xmss_core_sign_open(unsigned char *msg, unsigned long long *msglen, const unsigned char *sig_msg, unsigned long long sig_msg_len, const unsigned char *pk);
+int xmssmt_core_sign_open(unsigned char *msg, unsigned long long *msglen, const unsigned char *sig_msg, unsigned long long sig_msg_len, const unsigned char *pk);
 #endif
diff --git a/xmss.c b/xmss_core.c
similarity index 96%
rename from xmss.c
rename to xmss_core.c
index 52dcfc0..bf41356 100644
--- a/xmss.c
+++ b/xmss_core.c
@@ -5,7 +5,7 @@ Joost Rijneveld
 Public domain.
 */
 
-#include "xmss.h"
+#include "xmss_core.h"
 #include <stdlib.h>
 #include <string.h>
 #include <stdint.h>
@@ -120,7 +120,7 @@ static void compute_authpath_wots(unsigned char *root, unsigned char *authpath,
  * Format sk: [(32bit) idx || SK_SEED || SK_PRF || PUB_SEED || root]
  * Format pk: [root || PUB_SEED] omitting algo oid.
  */
-int xmss_keypair(unsigned char *pk, unsigned char *sk)
+int xmss_core_keypair(unsigned char *pk, unsigned char *sk)
 {
   // Set idx = 0
   sk[0] = 0;
@@ -147,7 +147,7 @@ int xmss_keypair(unsigned char *pk, unsigned char *sk)
  * 2. an updated secret key!
  *
  */
-int xmss_sign(unsigned char *sk, unsigned char *sm, unsigned long long *smlen, const unsigned char *m, unsigned long long mlen)
+int xmss_core_sign(unsigned char *sk, unsigned char *sm, unsigned long long *smlen, const unsigned char *m, unsigned long long mlen)
 {
   uint16_t i = 0;
 
@@ -246,7 +246,7 @@ int xmss_sign(unsigned char *sk, unsigned char *sm, unsigned long long *smlen, c
  * Format sk: [(ceil(h/8) bit) idx || SK_SEED || SK_PRF || PUB_SEED]
  * Format pk: [root || PUB_SEED] omitting algo oid.
  */
-int xmssmt_keypair(unsigned char *pk, unsigned char *sk)
+int xmssmt_core_keypair(unsigned char *pk, unsigned char *sk)
 {
   uint16_t i;
   // Set idx = 0
@@ -275,7 +275,7 @@ int xmssmt_keypair(unsigned char *pk, unsigned char *sk)
  * 2. an updated secret key!
  *
  */
-int xmssmt_sign(unsigned char *sk, unsigned char *sm, unsigned long long *smlen, const unsigned char *m, unsigned long long mlen)
+int xmssmt_core_sign(unsigned char *sk, unsigned char *sm, unsigned long long *smlen, const unsigned char *m, unsigned long long mlen)
 {
   uint64_t idx_tree;
   uint32_t idx_leaf;
diff --git a/xmss.h b/xmss_core.h
similarity index 58%
rename from xmss.h
rename to xmss_core.h
index fab17c6..39f0941 100644
--- a/xmss.h
+++ b/xmss_core.h
@@ -7,15 +7,15 @@ Public domain.
 
 #include "wots.h"
 
-#ifndef XMSS_H
-#define XMSS_H
+#ifndef XMSS_CORE_H
+#define XMSS_CORE_H
 
 /**
  * Generates a XMSS key pair for a given parameter set.
  * Format sk: [(32bit) idx || SK_SEED || SK_PRF || PUB_SEED || root]
  * Format pk: [root || PUB_SEED] omitting algo oid.
  */
-int xmss_keypair(unsigned char *pk, unsigned char *sk);
+int xmss_core_keypair(unsigned char *pk, unsigned char *sk);
 /**
  * Signs a message.
  * Returns
@@ -23,20 +23,20 @@ int xmss_keypair(unsigned char *pk, unsigned char *sk);
  * 2. an updated secret key!
  *
  */
-int xmss_sign(unsigned char *sk, unsigned char *sig_msg, unsigned long long *sig_msg_len, const unsigned char *msg, unsigned long long msglen);
+int xmss_core_sign(unsigned char *sk, unsigned char *sig_msg, unsigned long long *sig_msg_len, const unsigned char *msg, unsigned long long msglen);
 /**
  * Verifies a given message signature pair under a given public key.
  *
  * Note: msg and msglen are pure outputs which carry the message in case verification succeeds. The (input) message is assumed to be within sig_msg which has the form (sig||msg).
  */
-int xmss_sign_open(unsigned char *msg, unsigned long long *msglen, const unsigned char *sig_msg, unsigned long long sig_msg_len, const unsigned char *pk);
+int xmss_core_sign_open(unsigned char *msg, unsigned long long *msglen, const unsigned char *sig_msg, unsigned long long sig_msg_len, const unsigned char *pk);
 
 /*
  * Generates a XMSSMT key pair for a given parameter set.
  * Format sk: [(ceil(h/8) bit) idx || SK_SEED || SK_PRF || PUB_SEED || root]
  * Format pk: [root || PUB_SEED] omitting algo oid.
  */
-int xmssmt_keypair(unsigned char *pk, unsigned char *sk);
+int xmssmt_core_keypair(unsigned char *pk, unsigned char *sk);
 /**
  * Signs a message.
  * Returns
@@ -44,10 +44,10 @@ int xmssmt_keypair(unsigned char *pk, unsigned char *sk);
  * 2. an updated secret key!
  *
  */
-int xmssmt_sign(unsigned char *sk, unsigned char *sig_msg, unsigned long long *sig_msg_len, const unsigned char *msg, unsigned long long msglen);
+int xmssmt_core_sign(unsigned char *sk, unsigned char *sig_msg, unsigned long long *sig_msg_len, const unsigned char *msg, unsigned long long msglen);
 /**
  * Verifies a given message signature pair under a given public key.
  */
-int xmssmt_sign_open(unsigned char *msg, unsigned long long *msglen, const unsigned char *sig_msg, unsigned long long sig_msg_len, const unsigned char *pk);
+int xmssmt_core_sign_open(unsigned char *msg, unsigned long long *msglen, const unsigned char *sig_msg, unsigned long long sig_msg_len, const unsigned char *pk);
 #endif
 
diff --git a/xmss_fast.c b/xmss_core_fast.c
similarity index 97%
rename from xmss_fast.c
rename to xmss_core_fast.c
index fa2ff5a..31010b7 100644
--- a/xmss_fast.c
+++ b/xmss_core_fast.c
@@ -5,7 +5,7 @@ Joost Rijneveld
 Public domain.
 */
 
-#include "xmss_fast.h"
+#include "xmss_core_fast.h"
 #include <stdlib.h>
 #include <string.h>
 #include <stdint.h>
@@ -331,7 +331,7 @@ static void bds_round(bds_state *state, const unsigned long leaf_idx, const unsi
  * Format sk: [(32bit) idx || SK_SEED || SK_PRF || PUB_SEED || root]
  * Format pk: [root || PUB_SEED] omitting algo oid.
  */
-int xmss_keypair(unsigned char *pk, unsigned char *sk, bds_state *state)
+int xmss_core_keypair(unsigned char *pk, unsigned char *sk, bds_state *state)
 {
   // Set idx = 0
   sk[0] = 0;
@@ -359,7 +359,7 @@ int xmss_keypair(unsigned char *pk, unsigned char *sk, bds_state *state)
  * 2. an updated secret key!
  *
  */
-int xmss_sign(unsigned char *sk, bds_state *state, unsigned char *sm, unsigned long long *smlen, const unsigned char *m, unsigned long long mlen)
+int xmss_core_sign(unsigned char *sk, bds_state *state, unsigned char *sm, unsigned long long *smlen, const unsigned char *m, unsigned long long mlen)
 {
   uint16_t i = 0;
 
@@ -464,7 +464,7 @@ int xmss_sign(unsigned char *sk, bds_state *state, unsigned char *sm, unsigned l
  * Format sk: [(ceil(h/8) bit) idx || SK_SEED || SK_PRF || PUB_SEED || root]
  * Format pk: [root || PUB_SEED] omitting algo oid.
  */
-int xmssmt_keypair(unsigned char *pk, unsigned char *sk, bds_state *states, unsigned char *wots_sigs)
+int xmssmt_core_keypair(unsigned char *pk, unsigned char *sk, bds_state *states, unsigned char *wots_sigs)
 {
   unsigned char ots_seed[XMSS_N];
   int i;
@@ -501,7 +501,7 @@ int xmssmt_keypair(unsigned char *pk, unsigned char *sk, bds_state *states, unsi
  * 2. an updated secret key!
  *
  */
-int xmssmt_sign(unsigned char *sk, bds_state *states, unsigned char *wots_sigs, unsigned char *sm, unsigned long long *smlen, const unsigned char *m, unsigned long long mlen)
+int xmssmt_core_sign(unsigned char *sk, bds_state *states, unsigned char *wots_sigs, unsigned char *sm, unsigned long long *smlen, const unsigned char *m, unsigned long long mlen)
 {
   uint64_t idx_tree;
   uint32_t idx_leaf;
diff --git a/xmss_fast.h b/xmss_core_fast.h
similarity index 66%
rename from xmss_fast.h
rename to xmss_core_fast.h
index 575823d..2a35b2a 100644
--- a/xmss_fast.h
+++ b/xmss_core_fast.h
@@ -7,8 +7,8 @@ Public domain.
 
 #include "wots.h"
 
-#ifndef XMSS_H
-#define XMSS_H
+#ifndef XMSS_CORE_H
+#define XMSS_CORE_H
 
 typedef struct{
   unsigned int h;
@@ -39,7 +39,7 @@ void xmss_set_bds_state(bds_state *state, unsigned char *stack, int stackoffset,
  * Format sk: [(32bit) idx || SK_SEED || SK_PRF || PUB_SEED || root]
  * Format pk: [root || PUB_SEED] omitting algo oid.
  */
-int xmss_keypair(unsigned char *pk, unsigned char *sk, bds_state *state);
+int xmss_core_keypair(unsigned char *pk, unsigned char *sk, bds_state *state);
 /**
  * Signs a message.
  * Returns 
@@ -47,20 +47,20 @@ int xmss_keypair(unsigned char *pk, unsigned char *sk, bds_state *state);
  * 2. an updated secret key!
  * 
  */
-int xmss_sign(unsigned char *sk, bds_state *state, unsigned char *sig_msg, unsigned long long *sig_msg_len, const unsigned char *msg,unsigned long long msglen);
+int xmss_core_sign(unsigned char *sk, bds_state *state, unsigned char *sig_msg, unsigned long long *sig_msg_len, const unsigned char *msg,unsigned long long msglen);
 /**
  * Verifies a given message signature pair under a given public key.
  * 
  * Note: msg and msglen are pure outputs which carry the message in case verification succeeds. The (input) message is assumed to be within sig_msg which has the form (sig||msg). 
  */
-int xmss_sign_open(unsigned char *msg,unsigned long long *msglen, const unsigned char *sig_msg,unsigned long long sig_msg_len, const unsigned char *pk);
+int xmss_core_sign_open(unsigned char *msg,unsigned long long *msglen, const unsigned char *sig_msg,unsigned long long sig_msg_len, const unsigned char *pk);
 
 /*
  * Generates a XMSSMT key pair for a given parameter set.
  * Format sk: [(ceil(h/8) bit) idx || SK_SEED || SK_PRF || PUB_SEED || root]
  * Format pk: [root || PUB_SEED] omitting algo oid.
  */
-int xmssmt_keypair(unsigned char *pk, unsigned char *sk, bds_state *states, unsigned char *wots_sigs);
+int xmssmt_core_keypair(unsigned char *pk, unsigned char *sk, bds_state *states, unsigned char *wots_sigs);
 /**
  * Signs a message.
  * Returns 
@@ -68,10 +68,10 @@ int xmssmt_keypair(unsigned char *pk, unsigned char *sk, bds_state *states, unsi
  * 2. an updated secret key!
  * 
  */
-int xmssmt_sign(unsigned char *sk, bds_state *state, unsigned char *wots_sigs, unsigned char *sig_msg, unsigned long long *sig_msg_len, const unsigned char *msg, unsigned long long msglen);
+int xmssmt_core_sign(unsigned char *sk, bds_state *state, unsigned char *wots_sigs, unsigned char *sig_msg, unsigned long long *sig_msg_len, const unsigned char *msg, unsigned long long msglen);
 /**
  * Verifies a given message signature pair under a given public key.
  */
-int xmssmt_sign_open(unsigned char *msg, unsigned long long *msglen, const unsigned char *sig_msg, unsigned long long sig_msg_len, const unsigned char *pk);
+int xmssmt_core_sign_open(unsigned char *msg, unsigned long long *msglen, const unsigned char *sig_msg, unsigned long long sig_msg_len, const unsigned char *pk);
 #endif