pki: Rename ssh_pki_publickey_to_string and make it public.

include/libssh/libssh.h

@@ -440,6 +440,7 @@ LIBSSH_API int ssh_pki_import_pubkey_base64(ssh_session session,
 LIBSSH_API int ssh_pki_import_pubkey_blob(ssh_session session,
                                           const ssh_string key_blob,
                                           ssh_key *pkey);
+LIBSSH_API ssh_string ssh_pki_publickey_to_blob(const ssh_key key);
 
 LIBSSH_API int ssh_userauth_pki_pubkey(ssh_session session, const char *username,
                             ssh_string publickey, ssh_key privatekey);

include/libssh/pki.h

@@ -68,7 +68,6 @@ void ssh_key_clean (ssh_key key);
 ssh_key ssh_pki_publickey_from_privatekey(const ssh_key privkey);
 ssh_string ssh_pki_do_sign(ssh_session session, ssh_buffer sigbuf,
     ssh_key privatekey);
-ssh_string ssh_pki_publickey_to_string(const ssh_key key);
 
 /* temporary functions, to be removed after migration to ssh_key */
 ssh_public_key ssh_pki_convert_key_to_publickey(ssh_key key);

src/pki.c

@@ -622,14 +622,17 @@ ssh_key ssh_pki_publickey_from_privatekey(const ssh_key privkey) {
 }
 
 /**
- * @brief Create a ssh string from a public key.
+ * @brief Create a key_blob from a public key.
+ *
+ * The "key_blob" is encoded as per RFC 4253 section 6.6 "Public Key
+ * Algorithms" for any of the supported protocol 2 key types.
  *
  * @param[in] key       A public or private key to create the public ssh_string
  *                      from.
  *
- * @return              The string or NULL on error.
+ * @return              The key_blob or NULL on error.
  */
-ssh_string ssh_pki_publickey_to_string(const ssh_key key)
+ssh_string ssh_pki_publickey_to_blob(const ssh_key key)
 {
     if (key == NULL) {
         return NULL;