NAME

       clevis-encrypt-sss -- Encrypts using a Shamir's Secret Sharing policy

SYNOPSIS

       clevis encrypt sss CONFIG < PT > JWE

OVERVIEW

       The  clevis encrypt sss command encrypts using a Shamir's Secret Sharing policy.  Its only
       argument is the JSON configuration object.

       Shamir's Secret Sharing (SSS) provides a way to mix pins together to create  sophisticated
       unlocking and high availability policies.  SSS is a thresholding scheme.  It creates a key
       and divides it into a number of  pieces.   Each  piece  is  encrypted  using  another  pin
       (possibly even SSS recursively).  Additionally, you define the threshold t.  If at least t
       pieces can be decrypted, then the encryption key  can  be  recovered  and  decryption  can
       succeed.

       For example, let's create a high-availability setup using Tang:

              $ cfg='{"t":1,"pins":{"tang":[{"url":...},{"url":...}]}}'
              $ clevis encrypt sss "$cfg" < PT > JWE

       In  this  policy,  we  are  declaring  that  we  have a threshold of 1, but that there are
       multiple key fragments encrypted using different Tang servers.  Since our threshold is  1,
       so  long  as  any  of the Tang servers are available, decryption will succeed.  As always,
       decryption is simply:

              $ clevis decrypt < JWE > PT

CONFIG

       This command uses the following configuration properties:

       • t (integer) : Number of pins required for decryption (REQUIRED)

       • pins (object) : Pins used for encrypting fragments (REQUIRED)

       The format of the pins property is as follows:

              {PIN:CFG,...} OR {PIN:[CFG,CFG,...],...}

       When the list version of the format is used, multiple pins of that type will  receive  key
       fragments.

SEE ALSO

       clevis-encrypt-http(1), clevis-encrypt-tang(1), clevis-decrypt(1)

AUTHORS

       Nathaniel McCallum <npmccallum@redhat.com>.

                                          Sepember 2017                     CLEVIS-ENCRYPT-SSS(1)