extid

README

go-extid

It can be valuable to internally use a serial integer as an ID without revealing that ID to the outside world. go-extid uses AES-128 to convert to and from an external ID that cannot feasibly be decoded without the secret key.

This prevents outsiders from quantifying the usage of your application by observing the rate of increase of IDs as well as provides protection against brute force crawling of all resources.

Example Usage

prefix := "user"
key := []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}

et, err := extid.NewType(prefix, key)
if err != nil {
  return err
}

et.Encode(1) // => "user_13189a6ae4ab07ae70a3aabd30be99de"

Performance

$ go test -bench=. -benchmem
goos: darwin
goarch: amd64
pkg: github.com/jackc/go-extid
cpu: Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
BenchmarkEncode-16    	 8812752	       126.3 ns/op	     112 B/op	       4 allocs/op
BenchmarkDecode-16    	14138239	        78.88 ns/op	      32 B/op	       2 allocs/op
PASS
ok  	github.com/jackc/go-extid	5.298s

Other Implementations

• PostgreSQL
• Ruby

Documentation

Index

• type Type
  • func NewType(prefix string, key []byte) (*Type, error)
  • func (t *Type) Decode(s string) (int64, error)
  • func (t *Type) Encode(n int64) string

Examples

• Type.Encode

Types

type Type

type Type struct {
	// contains filtered or unexported fields
}

func NewType

func NewType(prefix string, key []byte) (*Type, error)

func (*Type) Decode

func (t *Type) Decode(s string) (int64, error)

func (*Type) Encode

func (t *Type) Encode(n int64) string

Example

prefix := "user"
key := []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}

et, err := extid.NewType(prefix, key)
if err != nil {
	fmt.Println(err)
	return
}

for i := 0; i < 5; i++ {
	fmt.Println(i, et.Encode(int64(i)))
}

Output:

0 user_c6a13b37878f5b826f4f8162a1c8d879
1 user_13189a6ae4ab07ae70a3aabd30be99de
2 user_c76e8fcf7ad0fe9b39e083739cbe26c2
3 user_90cb45611c3105c84624b2ac12cb5b74
4 user_79d0782401799c8fd25121e869b5b532