package cryptocore import ( "crypto/sha256" "log" "golang.org/x/crypto/hkdf" ) // hkdfDerive derives "outLen" bytes from "masterkey" and "info" using // HKDF-SHA256. // It returns the derived bytes or panics. func hkdfDerive(masterkey []byte, info string, outLen int) (out []byte) { h := hkdf.New(sha256.New, masterkey, nil, []byte(info)) out = make([]byte, outLen) n, err := h.Read(out) if n != outLen || err != nil { log.Panicf("hkdfDerive: hkdf read failed, got %d bytes, error: %v", n, err) } return out }