kubo/docs/specifications/keystore.md

Keystore

Authors(s):

• whyrusleeping
• Hector Sanjuan

Abstract

This spec provides definitions and operations for the keystore feature in IPFS.

Table of Contents

• Goals
• Planned Implementation
  • Key storage
  • Interface
  • Code changes and additions
  • Structures

Goals

To have a secure, simple and user-friendly way of storing and managing keys for use by ipfs. As well as the ability to share these keys, encrypt, decrypt, sign and verify data.

Planned Implementation

Key storage

Storage layout and format is defined in the repository_fs part of the spec.

Interface

ipfs key

USAGE
  ipfs key - Create and list IPNS name keypairs

  ipfs key

  'ipfs key gen' generates a new keypair for usage with IPNS and 'ipfs name
  publish'.
  
    > ipfs key gen --type=rsa --size=2048 mykey
    > ipfs name publish --key=mykey QmSomeHash
  
  'ipfs key list' lists the available keys.
  
    > ipfs key list
    self
    mykey
  		

SUBCOMMANDS
  ipfs key export <name>           - Export a keypair
  ipfs key gen <name>              - Create a new keypair
  ipfs key import <name> <key>     - Import a key and prints imported key id
  ipfs key list                    - List all local keypairs.
  ipfs key rename <name> <newName> - Rename a keypair.
  ipfs key rm <name>...            - Remove a keypair.
  ipfs key rotate                  - Rotates the IPFS identity.

  For more information about each command, use:
  'ipfs key <subcmd> --help'

ipfs crypt

NOTE: as of 2023 Q4, ipfs crypt commands are not implemented yet.

    ipfs crypt - Perform cryptographic operations using ipfs keypairs

SUBCOMMANDS:

    ipfs crypt sign <data>          - Generates a signature for the given data with a specified key
    ipfs crypt verify <data> <sig>  - Verify that the given data and signature match
    ipfs crypt encrypt <data>       - Encrypt the given data
    ipfs crypt decrypt <data>       - Decrypt the given data

DESCRIPTION:

    `ipfs crypt` is a command used to perform various cryptographic operations
    using ipfs keypairs, including: signing, verifying, encrypting and decrypting.

Some subcommands:

ipfs key Gen

USAGE
  ipfs key gen <name> - Create a new keypair

SYNOPSIS
  ipfs key gen [--type=<type> | -t] [--size=<size> | -s]
               [--ipns-base=<ipns-base>] [--] <name>

ARGUMENTS

  <name> - name of key to create

OPTIONS

  -t, --type   string - type of the key to create: rsa, ed25519. Default:
                        ed25519.
  -s, --size   int    - size of the key to generate.
  --ipns-base  string - Encoding used for keys: Can either be a multibase
                        encoded CID or a base58btc encoded multihash. Takes
                        {b58mh|base36|k|base32|b...}. Default: base36.

---

Key Send

USAGE
  ipfs key - Create and list IPNS name keypairs

SYNOPSIS
  ipfs key

DESCRIPTION

  'ipfs key gen' generates a new keypair for usage with IPNS and 'ipfs name
  publish'.
  
    > ipfs key gen --type=rsa --size=2048 mykey
    > ipfs name publish --key=mykey QmSomeHash
  
  'ipfs key list' lists the available keys.
  
    > ipfs key list
    self
    mykey
  		

SUBCOMMANDS
  ipfs key export <name>           - Export a keypair
  ipfs key gen <name>              - Create a new keypair
  ipfs key import <name> <key>     - Import a key and prints imported key id
  ipfs key list                    - List all local keypairs.
  ipfs key rename <name> <newName> - Rename a keypair.
  ipfs key rm <name>...            - Remove a keypair.
  ipfs key rotate                  - Rotates the IPFS identity.

  For more information about each command, use:
  'ipfs key <subcmd> --help'

Comments:

Ensure that the user knows the implications of sending a key.

---

Crypt Encrypt

    ipfs crypt encrypt <data> - Encrypt the given data with a specified key

ARGUMENTS:

    data                        - The filename of the data to be encrypted ("-" for stdin)

OPTIONS:

    -k, -key        string        - The name of the key to use for encryption (default: localkey)
    -o, -output     string        - The name of the output file (default: stdout)
    -c, -cipher     string        - The cipher to use for the operation
    -m, -mode       string        - The block cipher mode to use for the operation

DESCRIPTION:

    'ipfs crypt encrypt' is a command used to encypt data so that only holders of a certain
    key can read it.

Comments:

This should probably just operate on raw data and not on DAGs.

---

Other Interface Changes

We will also need to make additions to support keys in other commands, these changes are as follows:

• ipfs add

  • Support for a -encrypt-key option, for block encrypting the file being added with the key
    • also adds an 'encrypted' node above the root unixfs node
  • Support for a -sign-key option to attach a signature node above the root unixfs node

• ipfs block put

  • Support for a -encrypt-key option, for encrypting the block before hashing and storing

• ipfs object put

  • Support for a -encrypt-key option, for encrypting the object before hashing and storing

• ipfs name publish

  • Support for a -key option to select which keyspace to publish to

Code changes and additions

This sections outlines code organization around this feature.

Keystore package

The fsrepo carries a keystore that can be used to load/store keys. The keystore is implemented following this interface:

// Keystore provides a key management interface
type Keystore interface {
	// Has returns whether or not a key exist in the Keystore
	Has(string) (bool, error)
	// Put stores a key in the Keystore, if a key with the same name already exists, returns ErrKeyExists
	Put(string, ci.PrivKey) error
	// Get retrieves a key from the Keystore if it exists, and returns ErrNoSuchKey
	// otherwise.
	Get(string) (ci.PrivKey, error)
	// Delete removes a key from the Keystore
	Delete(string) error
	// List returns a list of key identifier
	List() ([]string, error)
}

Note: Never store passwords as strings, strings cannot be zeroed out after they are used. using a byte array allows you to write zeroes over the memory so that the users password does not linger in memory.

Unixfs

• new node types, 'encrypted' and 'signed', probably shouldn't be in unixfs, just understood by it

• if new node types are not unixfs nodes, special consideration must be given to the interop

• DagReader needs to be able to access keystore to seamlessly stream encrypted data we have keys for

  • also needs to be able to verify signatures

Importer

• DagBuilderHelper needs to be able to encrypt blocks
  • Dag Nodes should be generated like normal, then encrypted, and their parents should link to the hash of the encrypted node
• DagBuilderParams should have extra parameters to accommodate creating a DBH that encrypts the blocks

New 'Encrypt' package

Should contain code for crypto operations on dags.

Encryption of dags should work by first generating a symmetric key, and using that key to encrypt all the data. That key should then be encrypted with the public key chosen and stored in the Encrypted DAG structure.

Note: One option is to simply add it to the key interface.

Structures

Some tentative mockups (in json) of the new DAG structures for signing and encrypting

Signed DAG:

{
    "Links" : [
        {
            "Name":"@content",
            "Hash":"QmTheContent",
        }
    ],
    "Data": protobuf{
        "Type":"Signed DAG",
        "Signature": "thesignature",
        "PubKeyID": "QmPubKeyHash",
    }
}

Encrypted DAG:

{
    "Links" : [
        {
            "Name":"@content",
            "Hash":"QmRawEncryptedDag",
        }
    ],
    "Data": protobuf{
        "Type":"Encrypted DAG",
        "PubKeyID": "QmPubKeyHash",
        "Key": "ephemeral symmetric key, encrypted with public key",
    }
}