1crypt(1)                         User Commands                        crypt(1)
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NAME

6       crypt - encode or decode a file
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SYNOPSIS

9       crypt [password]
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DESCRIPTION

13       The  crypt  utility encrypts and decrypts the contents of a file. crypt
14       reads from the standard input and writes on the  standard  output.  The
15       password is a key that selects a particular transformation. If no pass‐
16       word is given, crypt demands a key from  the  terminal  and  turns  off
17       printing  while  the key is being typed in. crypt encrypts and decrypts
18       with the same key:
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20         example% crypt key < clear.file > encrypted.file
21         example% crypt key < encrypted.file | pr
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26       prints the contents of clear.file.
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29       Files encrypted by crypt are compatible with those treated by the  edi‐
30       tors ed(1), ex(1), and vi(1) in encryption mode.
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33       The  security  of encrypted files depends on three factors:  the funda‐
34       mental method must be hard to solve; direct search  of  the  key  space
35       must be infeasible; "sneak paths" by which keys or cleartext can become
36       visible must be minimized.
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39       crypt implements a one-rotor machine designed along the  lines  of  the
40       German Enigma, but with a 256-element rotor.  Methods of attack on such
41       machines are widely known, thus crypt provides minimal security.
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44       The transformation of a key into the internal settings of  the  machine
45       is  deliberately  designed to be expensive, that is, to take a substan‐
46       tial fraction of a second to compute.  However, if keys are  restricted
47       to  (say) three lower-case letters, then encrypted files can be read by
48       expending only a substantial fraction of five minutes of machine time.
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51       Since the key is an argument to the crypt command,  it  is  potentially
52       visible  to  users executing ps(1) or a derivative command. To minimize
53       this possibility, crypt takes care to destroy any  record  of  the  key
54       immediately  upon  entry.  No doubt the choice of keys and key security
55       are the most vulnerable aspect of crypt.
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FILES

58       /dev/tty    for typed key
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ATTRIBUTES

62       See attributes(5) for descriptions of the following attributes:
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67       ┌─────────────────────────────┬─────────────────────────────┐
68       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
69       ├─────────────────────────────┼─────────────────────────────┤
70       │Availability                 │SUNWcsu                      │
71       └─────────────────────────────┴─────────────────────────────┘
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SEE ALSO

74       des(1), ed(1), ex(1), ps(1), vi(1), attributes(5)
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78SunOS 5.11                        8 Mar 2005                          crypt(1)
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