diff --git a/include/libssh2.h b/include/libssh2.h
index f5d7bf27..d5d4e8ea 100644
--- a/include/libssh2.h
+++ b/include/libssh2.h
@@ -256,37 +256,37 @@ LIBSSH2_API LIBSSH2_SESSION *libssh2_session_init_ex(LIBSSH2_ALLOC_FUNC((*my_all
 LIBSSH2_API void **libssh2_session_abstract(LIBSSH2_SESSION *session);
 
 LIBSSH2_API void *libssh2_session_callback_set(LIBSSH2_SESSION *session, int cbtype, void *callback);
-LIBSSH2_API int libssh2_banner_set(LIBSSH2_SESSION *session, char *banner);
+LIBSSH2_API int libssh2_banner_set(LIBSSH2_SESSION *session, const char *banner);
 
 LIBSSH2_API int libssh2_session_startup(LIBSSH2_SESSION *session, int socket);
-LIBSSH2_API int libssh2_session_disconnect_ex(LIBSSH2_SESSION *session, int reason, char *description, char *lang);
+LIBSSH2_API int libssh2_session_disconnect_ex(LIBSSH2_SESSION *session, int reason, const char *description, const char *lang);
 #define libssh2_session_disconnect(session, description)	libssh2_session_disconnect_ex((session), SSH_DISCONNECT_BY_APPLICATION, (description), "")
 LIBSSH2_API void libssh2_session_free(LIBSSH2_SESSION *session);
 
-LIBSSH2_API char *libssh2_hostkey_hash(LIBSSH2_SESSION *session, int hash_type);
+LIBSSH2_API const char *libssh2_hostkey_hash(LIBSSH2_SESSION *session, int hash_type);
 
-LIBSSH2_API int libssh2_session_method_pref(LIBSSH2_SESSION *session, int method_type, char *prefs);
-LIBSSH2_API char *libssh2_session_methods(LIBSSH2_SESSION *session, int method_type);
+LIBSSH2_API int libssh2_session_method_pref(LIBSSH2_SESSION *session, int method_type, const char *prefs);
+LIBSSH2_API const char *libssh2_session_methods(LIBSSH2_SESSION *session, int method_type);
 LIBSSH2_API int libssh2_session_last_error(LIBSSH2_SESSION *session, char **errmsg, int *errmsg_len, int want_buf);
 
 LIBSSH2_API int libssh2_session_flag(LIBSSH2_SESSION *session, int flag, int value);
 
 /* Userauth API */
-LIBSSH2_API char *libssh2_userauth_list(LIBSSH2_SESSION *session, char *username, int username_len);
+LIBSSH2_API const char *libssh2_userauth_list(LIBSSH2_SESSION *session, const char *username, int username_len);
 LIBSSH2_API int libssh2_userauth_authenticated(LIBSSH2_SESSION *session);
-LIBSSH2_API int libssh2_userauth_password_ex(LIBSSH2_SESSION *session, char *username, int username_len, char *password, int password_len, LIBSSH2_PASSWD_CHANGEREQ_FUNC((*passwd_change_cb)));
+LIBSSH2_API int libssh2_userauth_password_ex(LIBSSH2_SESSION *session, const char *username, int username_len, const char *password, int password_len, LIBSSH2_PASSWD_CHANGEREQ_FUNC((*passwd_change_cb)));
 #define libssh2_userauth_password(session, username, password)	libssh2_userauth_password_ex((session), (username), strlen(username), (password), strlen(password), NULL)
 
-LIBSSH2_API int libssh2_userauth_publickey_fromfile_ex(LIBSSH2_SESSION *session, char *username, int username_len,
-																				 char *publickey, char *privatekey,
-																				 char *passphrase);
+LIBSSH2_API int libssh2_userauth_publickey_fromfile_ex(LIBSSH2_SESSION *session, const char *username, int username_len,
+																				 const char *publickey, const char *privatekey,
+																				 const char *passphrase);
 #define libssh2_userauth_publickey_fromfile(session, username, publickey, privatekey, passphrase)	\
 		libssh2_userauth_publickey_fromfile_ex((session), (username), strlen(username), (publickey), (privatekey), (passphrase))
-LIBSSH2_API int libssh2_userauth_hostbased_fromfile_ex(LIBSSH2_SESSION *session, char *username, int username_len,
-																				 char *publickey, char *privatekey,
-																				 char *passphrase,
-																				 char *hostname, int hostname_len,
-																				 char *local_username, int local_username_len);
+LIBSSH2_API int libssh2_userauth_hostbased_fromfile_ex(LIBSSH2_SESSION *session, const char *username, int username_len,
+																				 const char *publickey, const char *privatekey,
+																				 const char *passphrase,
+																				 const char *hostname, int hostname_len,
+																				 const char *local_username, int local_username_len);
 #define libssh2_userauth_hostbased_fromfile(session, username, publickey, privatekey, passphrase, hostname)	\
 		libssh2_userauth_hostbased_fromfile_ex((session), (username), strlen(username), (publickey), (privatekey), (passphrase), (hostname), strlen(hostname), (username), strlen(username))
 
@@ -296,7 +296,7 @@ LIBSSH2_API int libssh2_userauth_hostbased_fromfile_ex(LIBSSH2_SESSION *session,
  * array is already allocated. Responses data will be freed by libssh2
  * after callback return, but before subsequent callback invokation.
  */
-LIBSSH2_API int libssh2_userauth_keyboard_interactive_ex(LIBSSH2_SESSION* session, const char* username, int username_len,
+LIBSSH2_API int libssh2_userauth_keyboard_interactive_ex(LIBSSH2_SESSION* session, const char *username, int username_len,
 														 LIBSSH2_USERAUTH_KBDINT_RESPONSE_FUNC((*response_callback)));
 #define libssh2_userauth_keyboard_interactive(session, username, response_callback) \
         libssh2_userauth_keyboard_interactive_ex((session), (username), strlen(username), (response_callback))
@@ -315,7 +315,7 @@ LIBSSH2_API int libssh2_poll(LIBSSH2_POLLFD *fds, unsigned int nfds, long timeou
 
 #define SSH_EXTENDED_DATA_STDERR 1
 
-LIBSSH2_API LIBSSH2_CHANNEL *libssh2_channel_open_ex(LIBSSH2_SESSION *session, char *channel_type, int channel_type_len, int window_size, int packet_size, char *message, int message_len);
+LIBSSH2_API LIBSSH2_CHANNEL *libssh2_channel_open_ex(LIBSSH2_SESSION *session, const char *channel_type, int channel_type_len, int window_size, int packet_size, const char *message, int message_len);
 #define libssh2_channel_open_session(session)	libssh2_channel_open_ex((session), "session", sizeof("session") - 1, LIBSSH2_CHANNEL_WINDOW_DEFAULT, LIBSSH2_CHANNEL_PACKET_DEFAULT, NULL, 0)
 
 LIBSSH2_API LIBSSH2_CHANNEL *libssh2_channel_direct_tcpip_ex(LIBSSH2_SESSION *session, char *host, int port, char *shost, int sport);
@@ -337,7 +337,7 @@ LIBSSH2_API int libssh2_channel_request_pty_ex(LIBSSH2_CHANNEL *channel, char *t
 LIBSSH2_API int libssh2_channel_x11_req_ex(LIBSSH2_CHANNEL *channel, int single_connection, char *auth_proto, char *auth_cookie, int screen_number);
 #define libssh2_channel_x11_req(channel, screen_number)	libssh2_channel_x11_req_ex((channel), 0, NULL, NULL, (screen_number))
 
-LIBSSH2_API int libssh2_channel_process_startup(LIBSSH2_CHANNEL *channel, char *request, int request_len, char *message, int message_len);
+LIBSSH2_API int libssh2_channel_process_startup(LIBSSH2_CHANNEL *channel, const char *request, int request_len, const char *message, int message_len);
 #define libssh2_channel_shell(channel)					libssh2_channel_process_startup((channel), "shell", sizeof("shell") - 1, NULL, 0)
 #define libssh2_channel_exec(channel, command)			libssh2_channel_process_startup((channel), "exec", sizeof("exec") - 1, (command), strlen(command))
 #define libssh2_channel_subsystem(channel, subsystem)	libssh2_channel_process_startup((channel), "subsystem", sizeof("subsystem") - 1, (subsystem), strlen(subsystem))
@@ -362,7 +362,7 @@ LIBSSH2_API void libssh2_channel_set_blocking(LIBSSH2_CHANNEL *channel, int bloc
 LIBSSH2_API void libssh2_channel_handle_extended_data(LIBSSH2_CHANNEL *channel, int ignore_mode);
 /* libssh2_channel_ignore_extended_data() is defined below for BC with version 0.1
  * Future uses should use libssh2_channel_handle_extended_data() directly
- * if LIBSSH2_CHANNEL_EXTENDED_DATA_MERGE is passed, extended data will be read (FIFO) from the standard data channel 
+ * if LIBSSH2_CHANNEL_EXTENDED_DATA_MERGE is passed, extended data will be read (FIFO) from the standard data channel
  */
 /* DEPRECATED */
 #define libssh2_channel_ignore_extended_data(channel, ignore)		libssh2_channel_handle_extended_data((channel), (ignore) ? LIBSSH2_CHANNEL_EXTENDED_DATA_IGNORE : LIBSSH2_CHANNEL_EXTENDED_DATA_NORMAL )
@@ -378,8 +378,8 @@ LIBSSH2_API int libssh2_channel_eof(LIBSSH2_CHANNEL *channel);
 LIBSSH2_API int libssh2_channel_close(LIBSSH2_CHANNEL *channel);
 LIBSSH2_API int libssh2_channel_free(LIBSSH2_CHANNEL *channel);
 
-LIBSSH2_API LIBSSH2_CHANNEL *libssh2_scp_recv(LIBSSH2_SESSION *session, char *path, struct stat *sb);
-LIBSSH2_API LIBSSH2_CHANNEL *libssh2_scp_send_ex(LIBSSH2_SESSION *session, char *path, int mode, size_t size, long mtime, long atime);
+LIBSSH2_API LIBSSH2_CHANNEL *libssh2_scp_recv(LIBSSH2_SESSION *session, const char *path, struct stat *sb);
+LIBSSH2_API LIBSSH2_CHANNEL *libssh2_scp_send_ex(LIBSSH2_SESSION *session, const char *path, int mode, size_t size, long mtime, long atime);
 #define libssh2_scp_send(session, path, mode, size)					libssh2_scp_send_ex((session), (path), (mode), (size), 0, 0)
 
 LIBSSH2_API int libssh2_base64_decode(LIBSSH2_SESSION *session, char **dest, int *dest_len, char *src, int src_len);
diff --git a/include/libssh2_priv.h b/include/libssh2_priv.h
index cc414a4a..60be4700 100644
--- a/include/libssh2_priv.h
+++ b/include/libssh2_priv.h
@@ -264,7 +264,7 @@ struct _LIBSSH2_HOSTKEY_METHOD {
 	unsigned long hash_len;
 
 	int (*init)(LIBSSH2_SESSION *session, unsigned char *hostkey_data, unsigned long hostkey_data_len, void **abstract);
-	int (*initPEM)(LIBSSH2_SESSION *session, unsigned char *privkeyfile, unsigned char *passphrase, void **abstract);
+	int (*initPEM)(LIBSSH2_SESSION *session, unsigned const char *privkeyfile, unsigned const char *passphrase, void **abstract);
 	int (*sig_verify)(LIBSSH2_SESSION *session, const unsigned char *sig, unsigned long sig_len, const unsigned char *m, unsigned long m_len, void **abstract);
 	int (*sign)(LIBSSH2_SESSION *session, unsigned char **signature, unsigned long *signature_len, const unsigned char *data, unsigned long data_len, void **abstract);
 	int (*signv)(LIBSSH2_SESSION *session, unsigned char **signature, unsigned long *signature_len, unsigned long veccount, const struct iovec datavec[], void **abstract);
diff --git a/src/channel.c b/src/channel.c
index afc200bf..e91a11ca 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -105,8 +105,8 @@ LIBSSH2_CHANNEL *libssh2_channel_locate(LIBSSH2_SESSION *session, unsigned long
 /* {{{ libssh2_channel_open_session
  * Establish a generic session channel
  */
-LIBSSH2_API LIBSSH2_CHANNEL *libssh2_channel_open_ex(LIBSSH2_SESSION *session, char *channel_type, int channel_type_len, int window_size, int packet_size,
-																			   char *message, int message_len)
+LIBSSH2_API LIBSSH2_CHANNEL *libssh2_channel_open_ex(LIBSSH2_SESSION *session, const char *channel_type, int channel_type_len, int window_size, int packet_size,
+																			   const char *message, int message_len)
 {
 	unsigned char reply_codes[3] = { SSH_MSG_CHANNEL_OPEN_CONFIRMATION, SSH_MSG_CHANNEL_OPEN_FAILURE, 0 };
 	LIBSSH2_CHANNEL *channel = NULL;
@@ -664,7 +664,7 @@ LIBSSH2_API int libssh2_channel_x11_req_ex(LIBSSH2_CHANNEL *channel, int single_
 /* {{{ libssh2_channel_process_startup
  * Primitive for libssh2_channel_(shell|exec|subsystem)
  */
-LIBSSH2_API int libssh2_channel_process_startup(LIBSSH2_CHANNEL *channel, char *request, int request_len, char *message, int message_len)
+LIBSSH2_API int libssh2_channel_process_startup(LIBSSH2_CHANNEL *channel, const char *request, int request_len, const char *message, int message_len)
 {
 	LIBSSH2_SESSION *session = channel->session;
 	unsigned char *s, *packet, *data, reply_codes[3] = { SSH_MSG_CHANNEL_SUCCESS, SSH_MSG_CHANNEL_FAILURE, 0 }, local_channel[4];
diff --git a/src/hostkey.c b/src/hostkey.c
index 54afca93..62ca5535 100644
--- a/src/hostkey.c
+++ b/src/hostkey.c
@@ -109,7 +109,7 @@ static int libssh2_hostkey_method_ssh_rsadsa_passphrase_cb(char *buf, int size,
 /* {{{ libssh2_hostkey_method_ssh_rsa_initPEM
  * Load a Private Key from a PEM file
  */
-static int libssh2_hostkey_method_ssh_rsa_initPEM(LIBSSH2_SESSION *session, unsigned char *privkeyfile, unsigned char *passphrase, void **abstract)
+static int libssh2_hostkey_method_ssh_rsa_initPEM(LIBSSH2_SESSION *session, unsigned const char *privkeyfile, unsigned const char *passphrase, void **abstract)
 {
 	RSA *rsactx;
 	FILE *fp;
@@ -131,7 +131,7 @@ static int libssh2_hostkey_method_ssh_rsa_initPEM(LIBSSH2_SESSION *session, unsi
 		 */
 		OpenSSL_add_all_ciphers();
 	}
-	rsactx = PEM_read_RSAPrivateKey(fp, NULL, (void*)libssh2_hostkey_method_ssh_rsadsa_passphrase_cb, passphrase);
+	rsactx = PEM_read_RSAPrivateKey(fp, NULL, (void*)libssh2_hostkey_method_ssh_rsadsa_passphrase_cb, (void*)passphrase);
 	if (!rsactx) {
 		fclose(fp);
 		return -1;
@@ -323,7 +323,7 @@ static int libssh2_hostkey_method_ssh_dss_init(LIBSSH2_SESSION *session, unsigne
 /* {{{ libssh2_hostkey_method_ssh_dss_initPEM
  * Load a Private Key from a PEM file
  */
-static int libssh2_hostkey_method_ssh_dss_initPEM(LIBSSH2_SESSION *session, unsigned char *privkeyfile, unsigned char *passphrase, void **abstract)
+static int libssh2_hostkey_method_ssh_dss_initPEM(LIBSSH2_SESSION *session, unsigned const char *privkeyfile, unsigned const char *passphrase, void **abstract)
 {
 	DSA *dsactx;
 	FILE *fp;
@@ -345,7 +345,7 @@ static int libssh2_hostkey_method_ssh_dss_initPEM(LIBSSH2_SESSION *session, unsi
 		 */
 		OpenSSL_add_all_ciphers();
 	}
-	dsactx = PEM_read_DSAPrivateKey(fp, NULL, (void*)libssh2_hostkey_method_ssh_rsadsa_passphrase_cb, passphrase);
+	dsactx = PEM_read_DSAPrivateKey(fp, NULL, (void*)libssh2_hostkey_method_ssh_rsadsa_passphrase_cb, (void*)passphrase);
 	if (!dsactx) {
 		fclose(fp);
 		return -1;
@@ -523,7 +523,7 @@ LIBSSH2_HOSTKEY_METHOD **libssh2_hostkey_methods(void)
  * Length of buffer is determined by hash type
  * i.e. MD5 == 16, SHA1 == 20
  */
-LIBSSH2_API char *libssh2_hostkey_hash(LIBSSH2_SESSION *session, int hash_type)
+LIBSSH2_API const char *libssh2_hostkey_hash(LIBSSH2_SESSION *session, int hash_type)
 {
 	switch (hash_type) {
 #ifndef OPENSSL_NO_MD5
diff --git a/src/kex.c b/src/kex.c
index 618705d7..2edff14b 100644
--- a/src/kex.c
+++ b/src/kex.c
@@ -1287,7 +1287,7 @@ int libssh2_kex_exchange(LIBSSH2_SESSION *session, int reexchange) /* session->f
 /* {{{ libssh2_session_method_pref
  * Set preferred method
  */
-LIBSSH2_API int libssh2_session_method_pref(LIBSSH2_SESSION *session, int method_type, char *prefs)
+LIBSSH2_API int libssh2_session_method_pref(LIBSSH2_SESSION *session, int method_type, const char *prefs)
 {
 	char **prefvar, *s, *newprefs;
 	int prefs_len = strlen(prefs);
diff --git a/src/scp.c b/src/scp.c
index 2ad264ca..bcded368 100644
--- a/src/scp.c
+++ b/src/scp.c
@@ -44,7 +44,7 @@
 /* {{{ libssh2_scp_recv
  * Open a channel and request a remote file via SCP
  */
-LIBSSH2_API LIBSSH2_CHANNEL *libssh2_scp_recv(LIBSSH2_SESSION *session, char *path, struct stat *sb)
+LIBSSH2_API LIBSSH2_CHANNEL *libssh2_scp_recv(LIBSSH2_SESSION *session, const char *path, struct stat *sb)
 {
 	int path_len = strlen(path);
 	unsigned char *command, response[LIBSSH2_SCP_RESPONSE_BUFLEN];
@@ -330,11 +330,12 @@ LIBSSH2_API LIBSSH2_CHANNEL *libssh2_scp_recv(LIBSSH2_SESSION *session, char *pa
 /* {{{ libssh2_scp_send_ex
  * Send a file using SCP
  */
-LIBSSH2_API LIBSSH2_CHANNEL *libssh2_scp_send_ex(LIBSSH2_SESSION *session, char *path, int mode, size_t size, long mtime, long atime)
+LIBSSH2_API LIBSSH2_CHANNEL *libssh2_scp_send_ex(LIBSSH2_SESSION *session, const char *path, int mode, size_t size, long mtime, long atime)
 {
 	int path_len = strlen(path);
-	unsigned char *command, *base, response[LIBSSH2_SCP_RESPONSE_BUFLEN];
+	unsigned char *command, response[LIBSSH2_SCP_RESPONSE_BUFLEN];
 	unsigned long response_len, command_len = path_len + sizeof("scp -t ");
+	unsigned const char *base;
 	LIBSSH2_CHANNEL *channel;
 
 	if (mtime || atime) {
diff --git a/src/session.c b/src/session.c
index 4294ccdf..f2a95e17 100644
--- a/src/session.c
+++ b/src/session.c
@@ -172,7 +172,7 @@ static int libssh2_banner_send(LIBSSH2_SESSION *session)
 /* {{{ libssh2_banner_set
  * Set the local banner
  */
-LIBSSH2_API int libssh2_banner_set(LIBSSH2_SESSION *session, char *banner)
+LIBSSH2_API int libssh2_banner_set(LIBSSH2_SESSION *session, const char *banner)
 {
 	int banner_len = banner ? strlen(banner) : 0;
 
@@ -497,7 +497,7 @@ LIBSSH2_API void libssh2_session_free(LIBSSH2_SESSION *session)
 
 /* {{{ libssh2_session_disconnect_ex
  */
-LIBSSH2_API int libssh2_session_disconnect_ex(LIBSSH2_SESSION *session, int reason, char *description, char *lang)
+LIBSSH2_API int libssh2_session_disconnect_ex(LIBSSH2_SESSION *session, int reason, const char *description, const char *lang)
 {
 	unsigned char *s, *data;
 	unsigned long data_len, descr_len = 0, lang_len = 0;
@@ -547,7 +547,7 @@ LIBSSH2_API int libssh2_session_disconnect_ex(LIBSSH2_SESSION *session, int reas
  * NOTE: Currently lang_cs and lang_sc are ALWAYS set to empty string regardless of actual negotiation
  * Strings should NOT be freed
  */
-LIBSSH2_API char *libssh2_session_methods(LIBSSH2_SESSION *session, int method_type)
+LIBSSH2_API const char *libssh2_session_methods(LIBSSH2_SESSION *session, int method_type)
 {
 	/* All methods have char *name as their first element */
 	LIBSSH2_KEX_METHOD *method = NULL;
diff --git a/src/userauth.c b/src/userauth.c
index 414db1e1..d49911bd 100644
--- a/src/userauth.c
+++ b/src/userauth.c
@@ -49,7 +49,7 @@
  * Not a common configuration for any SSH server though
  * username should be NULL, or a null terminated string
  */
-LIBSSH2_API char *libssh2_userauth_list(LIBSSH2_SESSION *session, char *username, int username_len)
+LIBSSH2_API const char *libssh2_userauth_list(LIBSSH2_SESSION *session, const char *username, int username_len)
 {
 	unsigned char reply_codes[3] = { SSH_MSG_USERAUTH_SUCCESS, SSH_MSG_USERAUTH_FAILURE, 0 };
 	unsigned long data_len = username_len + 31; /* packet_type(1) + username_len(4) + service_len(4) + service(14)"ssh-connection" +
@@ -116,8 +116,8 @@ LIBSSH2_API int libssh2_userauth_authenticated(LIBSSH2_SESSION *session)
 /* {{{ libssh2_userauth_password
  * Plain ol' login
  */
-LIBSSH2_API int libssh2_userauth_password_ex(LIBSSH2_SESSION *session, char *username, int username_len,
-																					  char *password, int password_len,
+LIBSSH2_API int libssh2_userauth_password_ex(LIBSSH2_SESSION *session, const char *username, int username_len,
+																					  const char *password, int password_len,
 																					  LIBSSH2_PASSWD_CHANGEREQ_FUNC((*passwd_change_cb)))
 {
 	unsigned char *data, *s, reply_codes[4] = { SSH_MSG_USERAUTH_SUCCESS, SSH_MSG_USERAUTH_FAILURE, SSH_MSG_USERAUTH_PASSWD_CHANGEREQ, 0 };
@@ -235,7 +235,7 @@ LIBSSH2_API int libssh2_userauth_password_ex(LIBSSH2_SESSION *session, char *use
  */
 static int libssh2_file_read_publickey(LIBSSH2_SESSION *session, unsigned char **method, unsigned long *method_len,
 																 unsigned char **pubkeydata, unsigned long *pubkeydata_len,
-																 char *pubkeyfile)
+																 const char *pubkeyfile)
 {
 	FILE *fd;
 	char *pubkey = NULL, c, *sp1, *sp2, *tmp;
@@ -310,12 +310,12 @@ static int libssh2_file_read_publickey(LIBSSH2_SESSION *session, unsigned char *
 }
 /* }}} */
 
-/* {{{ libssh2_file_read_publickey
+/* {{{ libssh2_file_read_privatekey
  * Read a PEM encoded private key from an id_??? style file
  */
 static int libssh2_file_read_privatekey(LIBSSH2_SESSION *session,	LIBSSH2_HOSTKEY_METHOD **hostkey_method, void **hostkey_abstract,
-																	char *method, int method_len,
-																	char *privkeyfile, char *passphrase)
+																	const char *method, int method_len,
+																	const char *privkeyfile, const char *passphrase)
 {
 	LIBSSH2_HOSTKEY_METHOD **hostkey_methods_avail = libssh2_hostkey_methods();
 
@@ -349,11 +349,11 @@ static int libssh2_file_read_privatekey(LIBSSH2_SESSION *session,	LIBSSH2_HOSTKE
 /* {{{ libssh2_userauth_hostbased_fromfile_ex
  * Authenticate using a keypair found in the named files
  */
-LIBSSH2_API int libssh2_userauth_hostbased_fromfile_ex(LIBSSH2_SESSION *session, char *username, int username_len,
-                                                                                 char *publickey, char *privatekey,
-                                                                                 char *passphrase,
-																				 char *hostname, int hostname_len,
-																				 char *local_username, int local_username_len)
+LIBSSH2_API int libssh2_userauth_hostbased_fromfile_ex(LIBSSH2_SESSION *session, const char *username, int username_len,
+                                                                                 const char *publickey, const char *privatekey,
+                                                                                 const char *passphrase,
+																				 const char *hostname, int hostname_len,
+																				 const char *local_username, int local_username_len)
 {
 	LIBSSH2_HOSTKEY_METHOD *privkeyobj;
 	void *abstract;
@@ -480,9 +480,9 @@ LIBSSH2_API int libssh2_userauth_hostbased_fromfile_ex(LIBSSH2_SESSION *session,
 /* {{{ libssh2_userauth_publickey_fromfile_ex
  * Authenticate using a keypair found in the named files
  */
-LIBSSH2_API int libssh2_userauth_publickey_fromfile_ex(LIBSSH2_SESSION *session, char *username, int username_len,
-                                                                                 char *publickey, char *privatekey,
-                                                                                 char *passphrase)
+LIBSSH2_API int libssh2_userauth_publickey_fromfile_ex(LIBSSH2_SESSION *session, const char *username, int username_len,
+                                                                                 const char *publickey, const char *privatekey,
+                                                                                 const char *passphrase)
 {
 	LIBSSH2_HOSTKEY_METHOD *privkeyobj;
 	void *abstract;
diff --git a/ssh2_sample.c b/ssh2_sample.c
index 0c9213db..83c50306 100644
--- a/ssh2_sample.c
+++ b/ssh2_sample.c
@@ -17,7 +17,7 @@
 int main(int argc, char *argv[]) {
 	int sock, i, auth_pw = 1;
 	struct sockaddr_in sin;
-	char *fingerprint;
+	const char *fingerprint;
 	LIBSSH2_SESSION *session;
 	LIBSSH2_CHANNEL *channel;
 #ifdef WIN32