A .NET implementation of collision-resistant ids. You can read more about CUIDs from the official project website.
A command-line utility, cuidgen, is also available that implements the cuid.net library for those wishing to leverage CUIDs in scripting environments.
You can install cuid.net as a nuget package:
dotnet add package cuid.net
cuid.net supports the construction and use of both CUIDv1 (deprecated) and CUIDv2 instances.
Caution
CUIDv1 has been deprecated for security reasons. Efforts should be made towards migrating to Cuid2
.
Warning
It is possible to derive with a degree of certainty when and where a CUIDv1 has been created.
Note
Usage of CUIDv1 will emit the compiler warning VISLIB0001
.
Designed and optimized for horizontal scaling and binary searches, Cuid
is an immutable structure that can be a
potential alternative to Guid
for situations where a clean "string safe" unique and sortable identifier is needed and
where security is not of the upmost concern.
CUIDv1 values are composed of several data points which are base 36 encoded.
clbvi4441000007ld63liebkf
Segment | Source |
---|---|
c | CUIDv1 identifier |
lbvi4441 | Unix timestamp (in milliseconds) |
0000 | Session counter |
07ld | Client fingerprint (host process identifier + system hostname) |
63liebkf | Random data |
using Visus.Cuid;
// new
Cuid cuid = Cuid.NewCuid();
Console.WriteLine(cuid); // clbvi4441000007ld63liebkf
// constructor
Cuid cuid = new("clbvi4441000007ld63liebkf");
// explicit parsing
Cuid cuid = Cuid.Parse("clbvi4441000007ld63liebkf");
// implicit parsing
bool success = Cuid.TryParse("clbvi4441000007ld63liebkf", out Cuid cuid);
Cuid
fully implements IComparable
, IComparable<T>
, and IEquatable<T>
along with including Cuid.Empty
for
comparing against empty or uninitialized Cuid
objects.
Cuid
has built-in support for serialization either with System.Text.Json
or XmlSerializer
.
using Visus.Cuid;
// serialize
Cuid cuid = Cuid.NewCuid();
string json = JsonSerializer.Serialize(cuid);
Console.WriteLine(json); // "clbvi4441000007ld63liebkf"
// deserialize
Cuid cuid = JsonSerializer.Deserialize<Cuid>("\"clbvi4441000007ld63liebkf\"");
using Visus.Cuid;
// serialize
Cuid cuid = Cuid.NewCuid();
XmlSerializer serializer = new(typeof(Cuid));
XmlWriterSettings settings = new() { Indent = false };
using (StringWriter sw = new())
{
using XmlWriter xw = XmlWriter.Create(stringWriter, settings);
serializer.Serialize(xw, cuid);
Console.WriteLine(sw); // <?xml version="1.0" encoding="utf-16"?><cuid>clbvi4441000007ld63liebkf</cuid>
}
// deserialize
string xml = "<?xml version=\"1.0\" encoding=\"utf-16\"?><cuid>clbvi4441000007ld63liebkf</cuid>";
using (TextReader sr = new StringReader(xml))
{
using XmlReader xr = XmlReader.Create(sr);
Cuid cuid = (Cuid) serializer.Deserialize(xr);
}
Note
Cuid2
implements IEquatable<T>
but does not implement IComparable
or IComparable<T>
.
Cuid2
is an immutable structure that generates a cryptographically strong identity. Cuid2
is recommended for use
over Cuid
where security context is important. The length of the value can also be adjusted to be anywhere from 4
characters to 32 characters in length, the default is 24.
CUIDv2 values follow a different variable structure length than that of their predecessor. As such, there is no predefined pattern of how they will look once generated. However, with that said, they do use the following data sources:
Segments |
---|
Single character (a-z) randomly chosen as the prefix |
Unix timestamp (in milliseconds) |
32-byte array containing cryptographically strong random data |
Session counter value from a cryptographically weak random number generator |
32-byte array containing non-sensitive host information and padding with cryptographically strong random data |
The information is then combined and a SHA-512 (SHA-3 Keccak) salted hash is computed and then encoded into a base 36 string.
using Visus.Cuid;
// new (default length of 24)
Cuid2 cuid = new Cuid2();
Console.WriteLine(cuid); // x8kvch3q341xr1wa5ida3ns0
// new (with custom length)
Cuid2 cuid = new Cuid2(10);
Console.WriteLine(cuid); // rolaz6ek3u