Provided by: aespipe_2.4c-1_amd64 bug

NAME

       aespipe - AES encrypting or decrypting pipe

SYNOPSIS

       aespipe [options] <inputfile >outputfile

DESCRIPTION

       aespipe  reads from standard input and writes to standard output. It can be used to create
       and restore encrypted tar or cpio archives. It can be used to encrypt and decrypt loop-AES
       compatible  encrypted  disk  images.  aespipe encrypts and decrypts blocks of data. If you
       are looking for  general  purpose  encrypting  tool  that  preserves  data  size  at  byte
       granularity, then please take a look at GnuPG.

       The  AES  cipher  is  used  in  CBC  (cipher  block  chaining) mode. Data is encrypted and
       decrypted in 512 byte chains.  aespipe supports three key setup modes; single-key,  multi-
       key-v2  and  multi-key-v3  modes. Single-key mode uses simple sector IV and one AES key to
       encrypt and decrypt all data sectors. Multi-key-v2 mode uses cryptographically more secure
       MD5  IV  and 64 different AES keys to encrypt and decrypt data sectors.  In multi-key mode
       first key is used for first sector, second key for second sector, and so on.  Multi-key-v3
       is  same  as  multi-key-v2 except is uses one extra 65th key as additional input to MD5 IV
       computation. See -K option for more information about how to enable multi-key-v3 mode.

       Recommended key setup mode is multi-key-v3, which is based on gpg encrypted key files.  In
       this  mode,  the  passphrase is protected against optimized dictionary attacks via salting
       and key iteration of gpg. Passphrase length should be 20 characters or more.

       Single-key mode preserves input size at 16  byte  granularity.  Multi-key  mode  preserves
       input  size  at  512  byte  granularity. If input size is not multiple of 16 or 512 bytes,
       input data is padded with null bytes so that both input and output sizes are multiples  of
       16 or 512 bytes.

       If  "ulimit  -l"  is  set  to  "unlimited"  then  aespipe attempts to lock its RAM so that
       encryption keys do not leak to unencrypted swap. If "ulimit -l" is  something  other  than
       "unlimited" then aespipe will proceed without locked RAM.

OPTIONS

       -A gpgAgentSocket
              Read  passphrase  of gpg encrypted key file from gpg-agent instead of the terminal.
              aespipe runs gpg  to  decrypt  a  key  file,  and  gpg  talks  to  gpg-agent  using
              gpgAgentSocket.  Usually  this  data is in GPG_AGENT_INFO environment variable. The
              environment that is passed to gpg  is  very  minimal.   Normally  gpg  passes  some
              environment  variables  to  gpg-agent, but in this case, there aren't any. For best
              results, you may want to configure gpg-agent so that it "keeps" and  uses  its  own
              environment.   Defining   "keep-tty",   "keep-display"  and  "pinentry-program"  in
              $HOME/.gnupg/gpg-agent.conf configuration file is a good start.

       -C itercountk
              Runs hashed passphrase through itercountk thousand  iterations  of  AES-256  before
              using  it  for  data  encryption. This consumes lots of CPU cycles at program start
              time but not thereafter. In  combination  with  passphrase  seed  this  slows  down
              dictionary attacks. Iteration is not done in multi-key mode.

       -d     Decrypt  data.  If  this  option  is not specified, default operation is to encrypt
              data.

       -e encryption
              Following encryption types are recognized: AES128  (default),  AES192  and  AES256.
              Encryption  type  names  are  case  insensitive.  AES128  defaults to using SHA-256
              passphrase hash, AES192 defaults to  using  SHA-384  passphrase  hash,  and  AES256
              defaults to using SHA-512 passphrase hash.

       -G gpghome
              Set  gpg home directory to gpghome, so that gpg uses public/private keys on gpghome
              directory. This is  only  used  when  gpgkey  file  needs  to  be  decrypted  using
              public/private  keys.  If  gpgkey  file  is  encrypted  with symmetric cipher only,
              public/private keys are not required and this option has no effect.

       -H phash
              Uses phash function to  hash  passphrase.  Available  hash  functions  are  sha256,
              sha384,  sha512  and  rmd160.  unhashed1  and  unhashed2  functions  also exist for
              compatibility  with  some  obsolete  implementations.  Hash  type  names  are  case
              insensitive.

       -K gpgkey
              Passphrase  is  piped to gpg so that gpg can decrypt file gpgkey which contains the
              real keys that are used to encrypt data. If decryption requires public/private keys
              and  gpghome  is  not specified, all users use their own gpg public/private keys to
              decrypt gpgkey. Decrypted gpgkey should contain 1 or 64 or 65  keys,  each  key  at
              least 20 characters and separated by newline. If decrypted gpgkey contains 64 or 65
              keys, then aespipe is put to multi-key mode. 65th  key,  if  present,  is  used  as
              additional input to MD5 IV computation.

       -O sectornumber
              Set IV offset in 512 byte units. Default is zero. Data is encrypted in 512 byte CBC
              chains and each 512 byte chain starts with IV whose computation depends  on  offset
              within  the  data.  This  option  can  be used to start encryption or decryption in
              middle of some existing encrypted disk image.

       -p fdnumber
              Read the passphrase from file descriptor fdnumber instead of the  terminal.  If  -K
              option  is  not being used (no gpg key file), then aespipe attempts to read 65 keys
              from passwdfd, each key at least 20 characters and separated by newline. If aespipe
              successfully reads 64 or 65 keys, then aespipe is put to multi-key mode. If aespipe
              encounters end-of-file before 64 keys are read, then only  first  key  is  used  in
              single-key mode.

       -P cleartextkey
              Read the passphrase from file cleartextkey instead of the terminal. If -K option is
              not being used (no gpg key file), then  aespipe  attempts  to  read  65  keys  from
              cleartextkey,  each key at least 20 characters and separated by newline. If aespipe
              successfully reads 64 or 65 keys, then aespipe is put to multi-key mode. If aespipe
              encounters  end-of-file  before  64  keys  are read, then only first key is used in
              single-key mode. If both  -p  and  -P  options  are  used,  then  -p  option  takes
              precedence. These are equivalent:

              aespipe -p3 -K foo.gpg -e AES128 ...   3<someFileName

              aespipe -P someFileName -K foo.gpg -e AES128 ...

              In  first  line  of  above  example,  in  addition  to normal open file descriptors
              (0==stdin  1==stdout  2==stderr),  shell  opens  the  file  and  passes  open  file
              descriptor  to  started  aespipe  program. In second line of above example, aespipe
              opens the file itself.

       -q     Be quiet and don't complain about write errors.

       -S pseed
              Sets encryption passphrase seed pseed which is appended to user supplied passphrase
              before  hashing. Using different seeds makes dictionary attacks slower but does not
              prevent them if user supplied passphrase is guessable.  Seed is not used in  multi-
              key mode.

       -T     Asks passphrase twice instead of just once.

       -v     Verbose mode. Prints diagnostics to stderr about key length, single/multi key mode,
              and selected code optimizations (x86/amd64/padlock/intelaes).

       -w number
              Wait number seconds before asking passphrase.

RETURN VALUE

       aespipe returns 0 on success, nonzero on failure.

AVAILABILITY

       Source is available from http://loop-aes.sourceforge.net/

AUTHORS

       Jari Ruusu