diff --git a/tool/Makefile.am b/tool/Makefile.am
index 4a1657b..aa024a0 100644
--- a/tool/Makefile.am
+++ b/tool/Makefile.am
@@ -40,7 +40,7 @@ noinst_LTLIBRARIES = libpiv_cmd.la libpiv_util.la
 libpiv_cmd_la_SOURCES = cmdline.ggo cmdline.c cmdline.h
 libpiv_cmd_la_CFLAGS =
 
-libpiv_util_la_SOURCES = util.c util.h
+libpiv_util_la_SOURCES = util.c util.h openssl-compat.c
 libpiv_util_la_LIBADD = $(top_builddir)/lib/libykpiv.la $(OPENSSL_LIBS)
 
 cmdline.c cmdline.h: cmdline.ggo Makefile.am $(top_srcdir)/configure.ac
diff --git a/tool/openssl-compat.c b/tool/openssl-compat.c
new file mode 100644
index 0000000..b8b274b
--- /dev/null
+++ b/tool/openssl-compat.c
@@ -0,0 +1,53 @@
+/*
+ * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#if OPENSSL_VERSION_NUMBER < 0x10100000L
+
+#include <string.h>
+#include <openssl/engine.h>
+
+
+int RSA_set0_key(RSA *r, BIGNUM *n, BIGNUM *e, BIGNUM *d)
+{
+    /* If the fields n and e in r are NULL, the corresponding input
+     * parameters MUST be non-NULL for n and e.  d may be
+     * left NULL (in case only the public key is used).
+     */
+    if ((r->n == NULL && n == NULL)
+        || (r->e == NULL && e == NULL))
+        return 0;
+
+    if (n != NULL) {
+        BN_free(r->n);
+        r->n = n;
+    }
+    if (e != NULL) {
+        BN_free(r->e);
+        r->e = e;
+    }
+    if (d != NULL) {
+        BN_free(r->d);
+        r->d = d;
+    }
+
+    return 1;
+}
+
+void RSA_get0_key(const RSA *r,
+                  const BIGNUM **n, const BIGNUM **e, const BIGNUM **d)
+{
+    if (n != NULL)
+        *n = r->n;
+    if (e != NULL)
+        *e = r->e;
+    if (d != NULL)
+        *d = r->d;
+}
+
+#endif /* OPENSSL_VERSION_NUMBER */
diff --git a/tool/openssl-compat.h b/tool/openssl-compat.h
new file mode 100644
index 0000000..d5e9f7a
--- /dev/null
+++ b/tool/openssl-compat.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#ifndef LIBCRYPTO_COMPAT_H
+#define LIBCRYPTO_COMPAT_H
+
+#if OPENSSL_VERSION_NUMBER < 0x10100000L
+
+#include <openssl/rsa.h>
+#include <openssl/dsa.h>
+#include <openssl/ecdsa.h>
+#include <openssl/dh.h>
+#include <openssl/evp.h>
+
+int RSA_set0_key(RSA *r, BIGNUM *n, BIGNUM *e, BIGNUM *d);
+void RSA_get0_key(const RSA *r,
+                  const BIGNUM **n, const BIGNUM **e, const BIGNUM **d);
+
+#endif /* OPENSSL_VERSION_NUMBER */
+#endif /* LIBCRYPTO_COMPAT_H */
+
diff --git a/tool/util.c b/tool/util.c
index baea3f1..678de85 100644
--- a/tool/util.c
+++ b/tool/util.c
@@ -37,6 +37,7 @@
 #include <windows.h>
 #endif
 
+#include "openssl-compat.h"
 #include <openssl/evp.h>
 #include <openssl/x509.h>
 #include <openssl/rsa.h>
@@ -61,7 +62,7 @@ FILE *open_file(const char *file_name, int mode) {
 }
 
 unsigned char get_algorithm(EVP_PKEY *key) {
-  int type = EVP_PKEY_type(key->type);
+  int type = EVP_PKEY_type(EVP_PKEY_id(key));
   switch(type) {
     case EVP_PKEY_RSA:
       {
@@ -641,15 +642,17 @@ int SSH_write_X509(FILE *fp, X509 *x) {
   case EVP_PKEY_RSA2: {
     RSA *rsa;
     unsigned char n[256];
+    const BIGNUM *bn_n;
 
     char rsa_id[] = "\x00\x00\x00\x07ssh-rsa";
     char rsa_f4[] = "\x00\x00\x00\x03\x01\x00\x01";
 
     rsa = EVP_PKEY_get1_RSA(pkey);
+    RSA_get0_key(rsa, &bn_n, NULL, NULL);
 
-    set_component(n, rsa->n, RSA_size(rsa));
+    set_component(n, bn_n, RSA_size(rsa));
 
-    uint32_t bytes = BN_num_bytes(rsa->n);
+    uint32_t bytes = BN_num_bytes(bn_n);
     char len_buf[5];
     int len = 4;
 
diff --git a/tool/yubico-piv-tool.c b/tool/yubico-piv-tool.c
index 757e1c4..5bf5df4 100644
--- a/tool/yubico-piv-tool.c
+++ b/tool/yubico-piv-tool.c
@@ -42,6 +42,7 @@
 #include <windows.h>
 #endif
 
+#include "openssl-compat.h"
 #include <openssl/des.h>
 #include <openssl/pem.h>
 #include <openssl/pkcs12.h>
@@ -234,8 +235,7 @@ static bool generate_key(ykpiv_state *state, const char *slot,
         goto generate_out;
       }
 
-      rsa->n = bignum_n;
-      rsa->e = bignum_e;
+      RSA_set0_key(rsa, bignum_n, bignum_e, NULL);
       EVP_PKEY_set1_RSA(public_key, rsa);
     } else if(algorithm == algorithm_arg_ECCP256 || algorithm == algorithm_arg_ECCP384) {
       EC_GROUP *group;