-void verify_ssh_host_key(void *frontend, char *host, int port, char *keytype,
- char *keystr, char *fingerprint);
-void askalg(void *frontend, const char *algtype, const char *algname);
-int askappend(void *frontend, Filename filename);
+void pgp_fingerprints(void);
+/*
+ * verify_ssh_host_key() can return one of three values:
+ *
+ * - +1 means `key was OK' (either already known or the user just
+ * approved it) `so continue with the connection'
+ *
+ * - 0 means `key was not OK, abandon the connection'
+ *
+ * - -1 means `I've initiated enquiries, please wait to be called
+ * back via the provided function with a result that's either 0
+ * or +1'.
+ */
+int verify_ssh_host_key(void *frontend, char *host, int port, char *keytype,
+ char *keystr, char *fingerprint,
+ void (*callback)(void *ctx, int result), void *ctx);
+/*
+ * askalg has the same set of return values as verify_ssh_host_key.
+ */
+int askalg(void *frontend, const char *algtype, const char *algname,
+ void (*callback)(void *ctx, int result), void *ctx);
+/*
+ * askappend can return four values:
+ *
+ * - 2 means overwrite the log file
+ * - 1 means append to the log file
+ * - 0 means cancel logging for this session
+ * - -1 means please wait.
+ */
+int askappend(void *frontend, Filename filename,
+ void (*callback)(void *ctx, int result), void *ctx);