1CLEVIS-ENCRYPT-TAN(1)                                    CLEVIS-ENCRYPT-TAN(1)
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NAME

6       clevis-encrypt-tang - Encrypts using a Tang binding server policy
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SYNOPSIS

9       clevis encrypt tang CONFIG [-y] < PT > JWE
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OVERVIEW

12       The clevis encrypt tang command encrypts using a Tang binding server
13       policy. Its only argument is the JSON configuration object.
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15       Clevis provides support for the Tang network binding server. Tang
16       provides a stateless, lightweight alternative to escrows. Encrypting
17       data using the Tang pin works like this:
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19           $ clevis encrypt tang '{"url":"http://tang.srv"}' < PT > JWE
20           The advertisement contains the following signing keys:
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22           _OsIk0T-E2l6qjfdDiwVmidoZjA
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24           Do you wish to trust these keys? [ynYN] y
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26       To decrypt the data, just pass it to the clevis decrypt command:
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28           $ clevis decrypt < JWE > PT
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30       As you can see above, Tang utilizes a trust-on-first-use workflow. If
31       you already know the thumbprint of a trusted key, you can specify it in
32       the configuration at encryption time:
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34           $ cfg='{"url":"http://tang.srv","thp":"_OsIk0T-E2l6qjfdDiwVmidoZjA"}'
35           $ clevis encrypt tang "$cfg" < PT > JWE
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37       Obtaining the thumbprint of a trusted signing key is easy. If you have
38       access to the Tang server, simply execute:
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40           $ tang-show-keys <PORT>
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42       where <PORT> is the port that the Tang server is listening on.
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44       If tang-show-keys is not available, but you have access to the Tang
45       server’s database directory, you can execute this instead:
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47           $ jose jwk thp -i $DBDIR/$SIG.jwk
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49       Tang can also perform entirely offline encryption if you pre-share the
50       server advertisement. You can fetch the advertisement with a simple
51       command (just be careful your network isn’t compromised!):
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53           $ curl -f $URL/adv > adv.jws
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55       Once you have the advertisement file, just provide it:
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57           $ clevis encrypt tang '{"url":...,"adv":"adv.jws"}' < PT > JWE
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CONFIG

60       This command uses the following configuration properties:
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62       •   url (string) : The base URL of the Tang server (REQUIRED)
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64       •   thp (string) : The thumbprint of a trusted signing key
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66       •   adv (string) : A filename containing a trusted advertisement
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68       •   adv (object) : A trusted advertisement (raw JSON)
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OPTIONS

71       •   -y : Automatically answer yes for all questions. Use this option
72           for skipping the advertisement trust check. This can be useful in
73           automated deployments:
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75               $ clevis encrypt tang '{"url":...}' -y < PT > JWE
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SEE ALSO

78       clevis-decrypt(1)
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82                                  10/29/2021             CLEVIS-ENCRYPT-TAN(1)
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