/// <summary>
/// Generate a namespace GUID (V3 or V5) with a given algorithm
/// </summary>
/// <param name="namespaceId">The namespace we're generating the GUID in</param>
/// <param name="name">The name we're generating the GUID for</param>
/// <param name="version">The version to generate (MD5 or SHA1)</param>
/// <returns></returns>
private static UUID GenerateNameBased(System.Guid namespaceId, string name, GuidVersion version)
{
if (version != GuidVersion.MD5 && version != GuidVersion.SHA1)
{
throw new ArgumentException("version", "Name based guids can only be version 3, or 5");
}
if (String.IsNullOrEmpty(name))
{
throw new ArgumentNullException("name", "The name parameter cannot be empty or null");
}
byte[] nameBytes = Encoding.UTF8.GetBytes(name);
byte[] namespaceBytes = namespaceId.ToByteArray();
if (BitConverter.IsLittleEndian)
{
ToggleEndianess(namespaceBytes);
}
var hash = version == GuidVersion.MD5 ?
HashProvider.GenerateMD5Hash(namespaceBytes, nameBytes) :
HashProvider.GenerateSHA1Hash(namespaceBytes, nameBytes);
if (BitConverter.IsLittleEndian)
{
ToggleEndianess(hash);
}
return(GenerateFromComponents(
hash.Skip(Constants.TIMESTAMP_BYTE_INDEX).Take(Constants.TIME_BYTES_LENGTH).ToArray(),
hash.Skip(Constants.CLOCK_SEQUENCE_BYTE_INDEX).Take(Constants.CLOCK_SEQUENCE_BYTES_LENGTH).ToArray(),
hash.Skip(Constants.NODE_BYTE_INDEX).Take(Constants.NODE_BYTES_LENGTH).ToArray(),
version, GuidVariant.RFC4122));
}
public static Guid Create(Guid @namespace, byte[] name, GuidVersion version)
{
var namespaceBytes = @namespace.ToBigEndianByteArray();
byte[] hash;
using (var algorithm = version == GuidVersion.NameBasedMd5 ? MD5.Create() : SHA1.Create() as HashAlgorithm)
{
algorithm.TransformBlock(namespaceBytes, 0, namespaceBytes.Length, null, 0);
algorithm.TransformFinalBlock(name, 0, name.Length);
hash = algorithm.Hash;
}
var guidBytes = new byte[16];
Array.Copy(hash, 0, guidBytes, 0, 16);
GuidUtility.EndianSwap(guidBytes);
//Variant RFC4122
guidBytes[8] = (byte)((guidBytes[8] & 0x3F) | 0x80);//big-endian octet 8
//Version
guidBytes[7] = (byte)((guidBytes[7] & 0x0F) | ((int)version << 4));//big-endian octet 6
return(new Guid(guidBytes));
}
/// <summary>
/// Creates a named, MD5-based (version 3) GUID.
/// </summary>
/// <param name="namespace">The GUID that defines the namespace.</param>
/// <param name="name">The name within that namespace.</param>
/// <param name="version">The version of GUID to create.</param>
private static Guid CreateNamed(Guid @namespace, byte[] name, GuidVersion version)
{
var namespaceBytes = @namespace.ToBigEndianByteArray();
byte[] hash;
#pragma warning disable CA5351 // Do Not Use Broken Cryptographic Algorithms
#pragma warning disable CA5350 // Do Not Use Weak Cryptographic Algorithms
using (var algorithm = version == GuidVersion.NameBasedMd5 ? MD5.Create() : SHA1.Create() as HashAlgorithm)
#pragma warning restore CA5350 // Do Not Use Weak Cryptographic Algorithms
#pragma warning restore CA5351 // Do Not Use Broken Cryptographic Algorithms
{
algorithm.TransformBlock(namespaceBytes, 0, namespaceBytes.Length, null, 0);
algorithm.TransformFinalBlock(name, 0, name.Length);
hash = algorithm.Hash;
}
var guidBytes = new byte[16];
Array.Copy(hash, 0, guidBytes, 0, 16);
GuidUtility.EndianSwap(guidBytes);
// Variant RFC4122
guidBytes[8] = (byte)((guidBytes[8] & 0x3F) | 0x80); // big-endian octet 8
// Version
guidBytes[7] = (byte)((guidBytes[7] & 0x0F) | ((int)version << 4)); // big-endian octet 6
return(new Guid(guidBytes));
}
/// <summary>
/// Create
/// </summary>
/// <param name="namespace"></param>
/// <param name="name"></param>
/// <param name="version"></param>
/// <returns></returns>
public static Guid Create(Guid @namespace, byte[] name, GuidVersion version)
{
switch (version)
{
//Creates a random (version 4) GUID.
case GuidVersion.Random:
return(CreateRandom());
//Creates a named, MD5-based (version 3) GUID.
case GuidVersion.NameBasedMd5:
return(NamedGuidProvider.Create(@namespace, name, GuidVersion.NameBasedMd5));
//Creates a named, SHA1-based (version 5) GUID.
case GuidVersion.NameBasedSha1:
return(NamedGuidProvider.Create(@namespace, name, GuidVersion.NameBasedSha1));
case GuidVersion.TimeBased:
return(Create(CombStyle.NormalStyle));
//Creates a random (version 4) GUID.
default:
return(Guid.NewGuid());
}
}
/// <summary>
/// Generate a GUID from its components
/// </summary>
/// <param name="timeBytes">The time based component</param>
/// <param name="clockSequenceBytes">The clock sequence component</param>
/// <param name="nodeBytes">The node component</param>
/// <param name="version">The GUID version</param>
/// <param name="variant">The GUID variant</param>
/// <returns></returns>
private static UUID GenerateFromComponents(byte[] timeBytes, byte[] clockSequenceBytes, byte[] nodeBytes, GuidVersion version, GuidVariant variant)
{
var guidBytes = new byte[Constants.GUID_BYTES_LENGTH];
if (clockSequenceBytes == null)
{
throw new ArgumentException("Please specify the clock sequence bytes", "clockSequenceBytes");
}
if (nodeBytes == null)
{
throw new ArgumentException("Please specify the node bytes", "nodeBytes");
}
if (clockSequenceBytes.Length != Constants.CLOCK_SEQUENCE_BYTES_LENGTH)
{
throw new ArgumentException("The clock sequence bytes must be of length " + Constants.CLOCK_SEQUENCE_BYTES_LENGTH, "clockSequenceBytes");
}
if (nodeBytes.Length != Constants.NODE_BYTES_LENGTH)
{
throw new ArgumentException("The node bytes must be of length " + Constants.NODE_BYTES_LENGTH, "nodeBytes");
}
if (timeBytes.Length != Constants.TIME_BYTES_LENGTH)
{
throw new ArgumentException("The time bytes must be of length " + Constants.TIME_BYTES_LENGTH, "nodeBytes");
}
//Copy over the different byte segments
Array.Copy(timeBytes, 0, guidBytes, Constants.TIMESTAMP_BYTE_INDEX, Constants.TIME_BYTES_LENGTH);
Array.Copy(clockSequenceBytes, 0, guidBytes, Constants.CLOCK_SEQUENCE_BYTE_INDEX, Constants.CLOCK_SEQUENCE_BYTES_LENGTH);
Array.Copy(nodeBytes, 0, guidBytes, Constants.NODE_BYTE_INDEX, Constants.NODE_BYTES_LENGTH);
//To put in the variant, take the 9th byte and perform an and operation using 0x3f, followed by an or operation with 0x80.
//Put in the version
int maskVariant = 0x3f;
int shiftVariant = 0;
switch (variant)
{
case GuidVariant.FutureReserved:
maskVariant = 0x1F;
shiftVariant = 0xE0;
break;
case GuidVariant.MicrosoftReserved:
maskVariant = 0x1F;
shiftVariant = 0xC0;
break;
case GuidVariant.NCSReserved:
maskVariant = 0x0;
shiftVariant = 0x0;
break;
case GuidVariant.RFC4122:
maskVariant = 0x3f;
shiftVariant = 0x80;
break;
default:
maskVariant = 0x3f;
shiftVariant = 0;
break;
}
int maskVersion = 0x3f;
int shiftVersion = 0x3f;
switch (version)
{
case GuidVersion.DCE:
maskVersion = 0x0f;
shiftVersion = 0x20;
break;
case GuidVersion.MD5:
maskVersion = 0x0f;
shiftVersion = 0x30;
break;
case GuidVersion.Random:
maskVersion = 0x0f;
shiftVersion = 0x40;
break;
case GuidVersion.SHA1:
maskVersion = 0x0f;
shiftVersion = 0x50;
break;
case GuidVersion.Time:
maskVersion = 0x0f;
shiftVersion = 0x10;
break;
default:
maskVersion = 0x3f;
shiftVersion = 0;
break;
}
guidBytes[Constants.VARIANT_BYTE_INDEX] &= (byte)maskVariant;
guidBytes[Constants.VARIANT_BYTE_INDEX] |= (byte)shiftVariant;
guidBytes[Constants.VERSION_BYTE_INDEX] &= (byte)maskVersion;
guidBytes[Constants.VERSION_BYTE_INDEX] |= (byte)shiftVersion;
return(new UUID(new System.Guid(guidBytes)));
}
public GuidAttribute(GuidVersion version = (GuidVersion) ~0)
{
this.version = version;
}
