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.TH "CLEVIS\-ENCRYPT\-SSS" "1" "September 2017" "" ""
.hy
.SH NAME
.PP
clevis\-encrypt\-sss \-\- Encrypts using a Shamir\[aq]s Secret Sharing
policy
.SH SYNOPSIS
.PP
\f[C]clevis\ encrypt\ sss\f[] CONFIG < PT > JWE
.SH OVERVIEW
.PP
The \f[C]clevis\ encrypt\ sss\f[] command encrypts using a Shamir\[aq]s
Secret Sharing policy.
Its only argument is the JSON configuration object.
.PP
Shamir\[aq]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 \f[C]t\f[].
If at least \f[C]t\f[] pieces can be decrypted, then the encryption key
can be recovered and decryption can succeed.
.PP
For example, let\[aq]s create a high\-availability setup using Tang:
.IP
.nf
\f[C]
$\ cfg=\[aq]{"t":1,"pins":{"tang":[{"url":...},{"url":...}]}}\[aq]
$\ clevis\ encrypt\ sss\ "$cfg"\ <\ PT\ >\ JWE
\f[]
.fi
.PP
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:
.IP
.nf
\f[C]
$\ clevis\ decrypt\ <\ JWE\ >\ PT
\f[]
.fi
.SH CONFIG
.PP
This command uses the following configuration properties:
.IP \[bu] 2
\f[C]t\f[] (integer) : Number of pins required for decryption (REQUIRED)
.IP \[bu] 2
\f[C]pins\f[] (object) : Pins used for encrypting fragments (REQUIRED)
.PP
The format of the \f[C]pins\f[] property is as follows:
.IP
.nf
\f[C]
{PIN:CFG,...}\ OR\ {PIN:[CFG,CFG,...],...}
\f[]
.fi
.PP
When the list version of the format is used, multiple pins of that type
will receive key fragments.
.SH SEE ALSO
.PP
\f[C]clevis\-encrypt\-http\f[](1), \f[C]clevis\-encrypt\-tang\f[](1),
\f[C]clevis\-decrypt\f[](1)
.SH AUTHORS
Nathaniel McCallum <npmccallum@redhat.com>.