-taken from stdin, then you have to have 2 GiB of disk space for that
-temporary file and resulting encrypted packet. You can control where
-temporary file will be stored using @env{TMPDIR} environment variable.
-Encryption is performed with @url{https://cr.yp.to/chacha.html,
-ChaCha20} algorithm. Data is splitted on 128 KiB blocks. Each block is
-encrypted with increasing nonce counter.
+taken from @code{stdin}, then you have to have more than 2 GiB of disk space
+for that temporary file and resulting encrypted packet. You can control
+temporary file location directory with @env{TMPDIR} environment
+variable. Encryption is performed in AEAD mode with
+@url{https://cr.yp.to/chacha.html, ChaCha20}-@url{https://en.wikipedia.org/wiki/Poly1305, Poly1305}
+algorithms. Data is divided on 128 KiB blocks. Each block is encrypted
+with increasing nonce counter. File is deletes immediately after
+creation, so even if program crashes -- disk space will be reclaimed, no
+need in cleaning it up later.
+
+If @file{SRC} points to directory, then
+@url{https://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13_01, pax archive}
+will be created on the fly with directory contents and destination
+filename @file{.tar} appended. It @strong{won't} contain any entities
+metainformation, but modification time with the names. UID/GID are set
+to zero. Directories have 777 permissions, files have 666, for being
+friendly with @command{umask}. Also each entity will have comment like
+@verb{|Autogenerated by NNCP version X.Y.Z built with goXXX|}.