Generate UUID v3

Generate a name-based UUID v3 using MD5 hashing of namespace and name.

Code

Utilities

require 'digest'
ns_bytes = namespace.delete('-').scan(/../).map { |b| b.to_i(16) }.pack('C*')
hash = Digest::MD5.digest(ns_bytes + name)
bytes = hash.bytes
bytes[6] = (bytes[6] & 0x0f) | 0x30
bytes[8] = (bytes[8] & 0x3f) | 0x80
return '%08x-%04x-%04x-%04x-%012x' % [
  bytes[0..3].pack('C*').unpack1('N'),
  bytes[4..5].pack('C*').unpack1('n'),
  bytes[6..7].pack('C*').unpack1('n'),
  bytes[8..9].pack('C*').unpack1('n'),
  bytes[10..15].pack('C*').unpack1('Q>') & 0xffffffffffff
]

Parameters

namespace(string)

Namespace UUID (use DNS, URL, OID, or X500 namespace).

name(string)

Name to hash within the namespace.

Server

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