js-libp2p/src/keychain

js-libp2p-keychain

A secure key chain for libp2p in JavaScript

Features

• Manages the lifecycle of a key
• Keys are encrypted at rest
• Enforces the use of safe key names
• Uses encrypted PKCS 8 for key storage
• Uses PBKDF2 for a "stetched" key encryption key
• Enforces NIST SP 800-131A and NIST SP 800-132
• Uses PKCS 7: CMS (aka RFC 5652) to provide cryptographically protected messages
• Delays reporting errors to slow down brute force attacks

KeyInfo

The key management and naming service API all return a KeyInfo object. The id is a universally unique identifier for the key. The name is local to the key chain.

{
  name: 'rsa-key',
  id: 'QmYWYSUZ4PV6MRFYpdtEDJBiGs4UrmE6g8wmAWSePekXVW'
}

The key id is the SHA-256 multihash of its public key. The public key is a protobuf encoding containing a type and the DER encoding of the PKCS SubjectPublicKeyInfo.

Private key storage

A private key is stored as an encrypted PKCS 8 structure in the PEM format. It is protected by a key generated from the key chain's passPhrase using PBKDF2.

The default options for generating the derived encryption key are in the dek object. This, along with the passPhrase, is the input to a PBKDF2 function.

const defaultOptions = {
  //See https://cryptosense.com/parameter-choice-for-pbkdf2/
  dek: {
    keyLength: 512 / 8,
    iterationCount: 1000,
    salt: 'at least 16 characters long',
    hash: 'sha2-512'
  }
}

Physical storage

The actual physical storage of an encrypted key is left to implementations of interface-datastore. A key benifit is that now the key chain can be used in browser with the js-datastore-level implementation.

Cryptographic Message Syntax (CMS)

CMS, aka PKCS #7 and RFC 5652, describes an encapsulation syntax for data protection. It is used to digitally sign, digest, authenticate, or encrypt arbitrary message content. Basically, cms.encrypt creates a DER message that can be only be read by someone holding the private key.