Implements a special case (k = 2) of Adi Shamir's secret sharing algorithm. This allows secret files to be encrypted on disk and require two secret holders to decrypt it.
trustworthy init
This will create a new master key and ask for two users to be added who can decrypt the master key. The information about users and secrets is stored in trustworthy.yml. With all trustworthy commands you can also specify the configuration file to work with using -c or --config.
trustworthy init -c myconfig.yml
trustworthy add-key
The master key will be loaded so that a new user key can be added to the configuration.
trustworthy encrypt foo.txt
The master key will be loaded and then used to encrypt the file specified.
trustworthy decrypt foo.txt.tw
Decrypting works similar to encrypting, first the master key will be loaded and then used to decrypt the file.
The configuration uses ruby's YAML::Store to provide a simple transactional data store. The salt is used in combination with the user password to derive a key using scrypt. That derived key encrypts the point for Shamir's algorithm.
---
a-user:
salt: 400$8$23$38f426136db22836
encrypted_point: dzVzPvuzKsTJ7coFLki8tQ==--vGto+f9sQhRuPb+47rUI4oSZ7gaPGKiQtBIwB//wTcvuJOm9gyrLrjH74RKKJlkScBvYuMfnhQyn9T1bIw9obsBs4YsF8VxCsDPG26Ci82n9qOENod2pP4xVzmC4VWCnbi7Y4jS+Rgsq6xp3L2zG6Ci0GWO1bSQO8hFzaMpBiCirqMAGHf0m6Yzqu6h5NFtygcyNyxAY8YxX1oxa6Bj5UwefDKplVGTI0ZbQn9vtdwKFuwXZsv11g5+zLvvq54Z2UZ/AZu/scnhXopL5IZkiclTtX8LUi9Dob3Xpqtf6WXymudvVMG0JaxkUqqRCyWtLSFE3sNdwv+877cS8PglTIKxXIZTIh7FzdEgkLSStGnw=
another-user:
salt: 400$8$23$df3b3153ee94da81
encrypted_point: Shx/GRuOYz+Ts/5f5z1yDw==--1ulNtnX6Zi3z0t12TiCItE5H5dhZZONKcgt6yq1g2prJWd1q5c9ArL10BtK/9lSPoXMsyO8rURKZ3pCM4hzW043B1ksJQtyg6O71ilnSvP+4Yty8oH0SW67cGSgfkfUc0UkfcE2Osfy/YVkP/HH47qTLNTg406uJ2uWjb6OkW8sjD+mq3hp8tehyy20tEBhqyM0UOSCpvhb+EgFfYFDeG+8Gj+r4lfcdqJJvzcy5U17tpYknQm/WbnmIkvgZRFGH/NIthJdPnK43SsdPbVcSHdkw71urJ3pBmgCmyTFcdmpiSl/t1rG09f2KT63YDF+4YUSn1fuIFZXbrLez59svHbKnQ8YHvt9pCXiQHelk8Sk=
- Introducing Trustworthy - http://jtdowney.com/blog/2013/08/01/introducing-trustworthy/
- RSA Labs - http://www.rsa.com/rsalabs/node.asp?id=2259
- ssss - http://point-at-infinity.org/ssss/
- Secret sharing on Wikipedia - http://en.wikipedia.org/wiki/Secret_sharing