tfcrypt is actually a frontend for Threefish with (by default) XTS mode of operation.
As a key it uses either password or keyfile, which is then hashed many times
-with Skein hash function. Default key length is 1280 bits (160 bytes).
+with Skein hash function.
This program is incompatible with older, "tf1024" tfcrypt version. This version aims to
provide a portable encryption tool to encrypt fixed media such as disks and archive files,
-as well as to provide decades long privacy for encrypted data. That's why it uses 1024 bit
-encryption and, unlike older version, extends key size to 1280 bits, eliminates tweak feature
-from Threefish and uses either XTS (by default) or OCB modes of operation instead,
-to encrypt fixed media in a secure undetectable way.
-
+as well as to provide decades long privacy for encrypted data.
Supported modes of operation: CTR, ECB, CBC, XTS, OCB and arbitrary long keystream.
OCB mode does not use Skein hash function to hash and verify message, instead, it does
a single pass crypt and verify, thus, it is faster than other modes when both crypt and verify.
+Additionally, this version provides a way to virtually "extend" key size to 1280 bits,
+by enabling "fullkey" option or changing "do_full_key" default setting in tfcrypt_defs.h.
+In this mode, tweak is ignored, and filled with extended key material.
+
THREEFISH NOTES
Please note that this encryption software includes Threefish cipher, which is terribly
Threefish contained here is stripped off of it's tweak property, thus, it is turned into a
regular block cipher. To add tweakability, either XTS or OCB modes of operation are used.
-Default wide block size is 4096 bytes. Author strongly believes that Threefish _may_ be subject
-to related key attacks when used in a tweaked mode, so this property is easy to remove.
-Because tweak occupied another 192 bits of key material, these 192 bits are added to effective
-key length. Another key word is extracted from the sum of all the user key words, thus,
-another 64 bits. Total +256 additional bits of key = 1280 key bits.
+Default wide block size is 4096 bytes.
SKEIN NOTES
This tfcrypt, unlike it's previous version, is copyrighted:
- Copyright (C) Andrey Rys <rys@lynxlynx.ru>, 2012-2018.
+ Copyright (C) Andrey Rys <rys@lynxlynx.ru>, 2012-2019.
It maybe freely used by anyone who agrees to the terms and conditions of the MIT license.