-Encryption is performed with
-@url{https://www.schneier.com/academic/twofish/, Twofish} algorithm, 256
-bit random key, zero IV, in
-@url{https://en.wikipedia.org/wiki/Counter_mode#Counter_.28CTR.29, CTR}
-mode.
+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.