import { Keychain } from '@peerbit/keychain' 

class KeychainDB extends Program implements Keychain, EncryptionProvider ? 
{
    @field({type:  Documents<Key>}}
    keys: Documents<Key>

    async open() {

          await this.keys.open({ encryption: new EncryptionProvider(this) }} // create a encryption provider from 'this' because 'this' implements Keychain interface 
   }

   async addKey(key: Key) {
        return this.keys.put(key, { encryption: { specific encryption options }}
   }

}

import { KeychainDB } from '@peerbit/keychain'


class MySpecialDBAndKeychain extends Program 
{
    @field({type: KeychainProgram}}
    keychain: KeychainProgram

    @field({type: Posts}}
    posts: Posts

    async open() {
          await this.keychain.open()
          await this.posts.open( { encryption: this.keychain.encryption }  )  // use custom encryption provider  (layer 1)
   }

   async createPost(content: string) {
        return this.posts.put(new Post(content))
   }

}