**throw new Error(‘must provide either options.secret or both options.encryptionKey and options.signingKey’);

**

const mongoose = require("mongoose");
const encrypt = require("mongoose-encryption");

const userSchema = new mongoose.Schema({
    email: {
        type: String,
        required: true
    },
    password: {
        type: String,     
        required: true 
    },
    createdOn: {
        type: Date,
        default: Date.now
    }
})

const encKey = process.env.ENC_KEY;
userSchema.plugin(encrypt, {secret: encKey, encryptedFields: ['password']});

module.exports = mongoose.model("user", userSchema);

I tried using mongoose-encryption but it fails.