waku-org/go-waku

package protocol

import (
    "crypto/rand"
    "sync"

    "github.com/cruxic/go-hmac-drbg/hmacdrbg"
    "github.com/waku-org/go-waku/waku/v2/utils"
    "go.uber.org/zap"
)

var brHmacDrbgPool = sync.Pool{New: func() interface{} {
    seed := make([]byte, 48)
    _, err := rand.Read(seed)
    if err != nil {
        utils.Logger().Fatal("rand.Read err", zap.Error(err))
    }
    return hmacdrbg.NewHmacDrbg(256, seed, nil)
}}

// GenerateRequestID generates a random 32 byte slice that can be used for
// creating requests inf the filter, store and lightpush protocols
func GenerateRequestID() []byte {
    rng := brHmacDrbgPool.Get().(*hmacdrbg.HmacDrbg)
    defer brHmacDrbgPool.Put(rng)

    randData := make([]byte, 32)
    if !rng.Generate(randData) {
        //Reseed is required every 10,000 calls
        seed := make([]byte, 48)
        _, err := rand.Read(seed)
        if err != nil {
            utils.Logger().Fatal("rand.Read err", zap.Error(err))
        }
        err = rng.Reseed(seed)
        if err != nil {
            //only happens if seed < security-level
            utils.Logger().Fatal("rng.Reseed err", zap.Error(err))
        }

        if !rng.Generate(randData) {
            utils.Logger().Error("could not generate random request id")
        }
    }
    return randData
}