envelope - SSKR Example

This example demonstrates the use of SSKR to shard a symmetric key that encrypted a message. The shares are then enclosed in individual envelopes and the seed can be recovered from those shares, allowing the future decryption of the message.

Dan has a cryptographic seed he wants to backup using a social recovery scheme. The seed includes metadata he wants to back up also, making it too large to fit into a basic SSKR share.

DAN_SEED=ur:seed/oxadgdhkwzdtfthptokigtvwnnjsqzcxknsktdaosezofptpbtlnlyjzkefmaxkpfyhsjpjecxgdkpjpjojzihcxfpjskphscxgsjlkoihaakskggsjljpihjncxinjojkkpjncxiejljzjljpcxjkinjycxhsjnihjydwcxiajljtjkihiajyihjykpjpcxhsieinjoinjkiainjtiocxihjzinjydwcxjkihiecxiejlcxihinkpjkjnjliecxjyihjnjojljpcxinjtiainieiniekpjtjycxkpjycxjzhsidjljpihcxihjycxiejljzjljpihcxjnhsiojthscxhsjzinjskphsdmluwmoxny

Dan encloses his seed in an envelope.

DAN_ENVELOPE=`envelope subject type ur $DAN_SEED`
echo $DAN_ENVELOPE

│ ur:envelope/tpsotantjzoxadgdhkwzdtfthptokigtvwnnjsqzcxknsktdaosezofptpbtlnlyjzkefmaxkpfyhsjpjecxgdkpjpjojzihcxfpjskphscxgsjlkoihaakskggsjljpihjncxinjojkkpjncxiejljzjljpcxjkinjycxhsjnihjydwcxiajljtjkihiajyihjykpjpcxhsieinjoinjkiainjtiocxihjzinjydwcxjkihiecxiejlcxihinkpjkjnjliecxjyihjnjojljpcxinjtiainieiniekpjtjycxkpjycxjzhsidjljpihcxihjycxiejljzjljpihcxjnhsiojthscxhsjzinjskphsdmfmflcnfy

Dan examines the contents of his envelope.

envelope format $DAN_ENVELOPE

│ Seed

Dan generates a public/private key pair that will allow him to recover his seed from any single share if he retains his private key.

envelope generate keypairs | read DAN_PRIVATE_KEY DAN_PUBLIC_KEY

Dan splits the envelope into a single group 2-of-3. The output of the envelope tool contains the list of share envelopes separated by spaces. He then assigns this to a shell array.

SHARE_ENVELOPES=(`envelope sskr split -g 2-of-3 --recipient $DAN_PUBLIC_KEY $DAN_ENVELOPE`)

Dan sends one envelope to each of Alice, Bob, and Carol.

SHARE_ENVELOPE_ALICE=${SHARE_ENVELOPES[1]}
SHARE_ENVELOPE_BOB=${SHARE_ENVELOPES[2]}
SHARE_ENVELOPE_CAROL=${SHARE_ENVELOPES[3]}

Dan ➡️ ☁️ ➡️ Alice, Bob, Carol

Bob examines the contents of his envelope, but can't recover the original seed: the SSKR share can only recover the seed with a threshold of other shares, and the SealedMessage can only be decrypted by Dan's private key.

envelope format $SHARE_ENVELOPE_BOB

│ ENCRYPTED [
│     'hasRecipient': SealedMessage
│     'sskrShare': SSKRShare
│ ]

By himself, Bob can't recover the seed.

envelope sskr join $SHARE_ENVELOPE_BOB

│ Error: invalid SSKR shares

At some future point, Dan retrieves two of the three envelopes so he can recover his seed.

envelope sskr join $SHARE_ENVELOPE_BOB $SHARE_ENVELOPE_CAROL | envelope extract ur

│ ur:seed/oxadgdhkwzdtfthptokigtvwnnjsqzcxknsktdaosezofptpbtlnlyjzkefmaxkpfyhsjpjecxgdkpjpjojzihcxfpjskphscxgsjlkoihaakskggsjljpihjncxinjojkkpjncxiejljzjljpcxjkinjycxhsjnihjydwcxiajljtjkihiajyihjykpjpcxhsieinjoinjkiainjtiocxihjzinjydwcxjkihiecxiejlcxihinkpjkjnjliecxjyihjnjojljpcxinjtiainieiniekpjtjycxkpjycxjzhsidjljpihcxihjycxiejljzjljpihcxjnhsiojthscxhsjzinjskphsdmluwmoxny

Dan can also recover his seed from a single share by decrypting it with his private key.

envelope decrypt --recipient $DAN_PRIVATE_KEY $SHARE_ENVELOPE_BOB | envelope extract wrapped | envelope extract ur

│ ur:seed/oxadgdhkwzdtfthptokigtvwnnjsqzcxknsktdaosezofptpbtlnlyjzkefmaxkpfyhsjpjecxgdkpjpjojzihcxfpjskphscxgsjlkoihaakskggsjljpihjncxinjojkkpjncxiejljzjljpcxjkinjycxhsjnihjydwcxiajljtjkihiajyihjykpjpcxhsieinjoinjkiainjtiocxihjzinjydwcxjkihiecxiejlcxihinkpjkjnjliecxjyihjnjojljpcxinjtiainieiniekpjtjycxkpjycxjzhsidjljpihcxihjycxiejljzjljpihcxjnhsiojthscxhsjzinjskphsdmluwmoxny