| Matthias Andreas Benkard | 832a54e | 2019-01-29 09:27:38 +0100 | [diff] [blame^] | 1 | // Copyright 2011 Google Inc. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | package uuid |
| 6 | |
| 7 | // Random returns a Random (Version 4) UUID or panics. |
| 8 | // |
| 9 | // The strength of the UUIDs is based on the strength of the crypto/rand |
| 10 | // package. |
| 11 | // |
| 12 | // A note about uniqueness derived from from the UUID Wikipedia entry: |
| 13 | // |
| 14 | // Randomly generated UUIDs have 122 random bits. One's annual risk of being |
| 15 | // hit by a meteorite is estimated to be one chance in 17 billion, that |
| 16 | // means the probability is about 0.00000000006 (6 × 10−11), |
| 17 | // equivalent to the odds of creating a few tens of trillions of UUIDs in a |
| 18 | // year and having one duplicate. |
| 19 | func NewRandom() UUID { |
| 20 | uuid := make([]byte, 16) |
| 21 | randomBits([]byte(uuid)) |
| 22 | uuid[6] = (uuid[6] & 0x0f) | 0x40 // Version 4 |
| 23 | uuid[8] = (uuid[8] & 0x3f) | 0x80 // Variant is 10 |
| 24 | return uuid |
| 25 | } |