Announcement: Gordian Guardian and Keytool now support requests, responses, and non-derivable keys.

[wolfmcnally]

Blockchain Commons has released Gordian Guardian beta 1.0 (14) for iOS and Keytool 0.6.0 for the command line.

Gordian Guardian is a cryptographic seed manager for iOS that generates and securely stores seeds, derives HD keys from them, can use SSKR to create sharded seed backups, and more.

Keytool is a command-line tool that implements a data flow graph for deriving cryptocurrency keys and addresses, and signing transactions. Any of the nodes in the graph can be assigned and any set of nodes can be derived as long as their dependencies are met. Keytool works seamlessly with our seed generation and transformation tool Seedtool.

New in Gordian Guardian

• Join the Gordian Guardian Test Flight.
• The Scan function now has a "Paste" button at the bottom. This allows a ur:crypto-seed or ur:crypto-request on the clipboard to be entered as if the same UR was scanned in a QR code.
• In the Derive and Export Key parameters area there is a new "Allows further derivation" toggle. When this is turned off, the derived key will not have a chain code, and therefore cannot be used to derived further keys.
• Now supports the is-derivable flag for key requests and responses. More Information.
• To facilitate testing, a set of requests for non-derivable keys have been added to our test vector PDF file.

New in Keytool

• Support for non-derivable keys via the is-derivable node.
• UR is now the primary format for types that support it, e.g. master-key. Such nodes can still take other forms of input (for example HD Key nodes can take UR or Base58) but output in Base58 is now done via separate nodes (e.g., master-key-base58).
• network is no longer derived from asset; they are separate. The two supported assets are currently Bitcoin btc and Ethereum eth. To use Bitcoin Testnet, use asset btc (the default) and network testnet.
• Support for ur:crypto-request and ur:crypto-response types for requesting and returning seeds and derived keys.

About Derivable and Non-Derivable Keys

Hierarchical Deterministic (HD) keys contain a field called the "chain code" that enables a key to be used to derive further keys. If the chain code is omitted, the key can still be used to produce Elliptic Curve (EC) keys used to verify transactions (or sign them if it is private key), but no further HD keys can be derived from it. The ur:crypto-hdkey format supports such "non-derivable" keys, and Keytool enables generating and using such keys via the is-derivable node. The is-derivable node contains a boolean value that, if set to false, causes keys derived from the address-key or derived-key nodes to be non-derivable. In addition, setting is-derivable to false causes generated ur:crypto-requests for keys to become requests for non-derivable keys, and causes generated ur:crypto-responses to produce non-derivable keys.

Gordian Guardian now also supports exporting non-derivable keys, and responds to airgapped requests for non-derivable keys.