System.Formats.Asn1
9.0.0
Prefix Reserved
dotnet add package System.Formats.Asn1 --version 9.0.0
NuGet\Install-Package System.Formats.Asn1 -Version 9.0.0
<PackageReference Include="System.Formats.Asn1" Version="9.0.0" />
paket add System.Formats.Asn1 --version 9.0.0
#r "nuget: System.Formats.Asn1, 9.0.0"
// Install System.Formats.Asn1 as a Cake Addin #addin nuget:?package=System.Formats.Asn1&version=9.0.0 // Install System.Formats.Asn1 as a Cake Tool #tool nuget:?package=System.Formats.Asn1&version=9.0.0
About
Provides functionality for parsing, encoding, and decoding data using Abstract Syntax Notation One (ASN.1). ASN.1 is a standard interface description language for defining data structures that can be serialized and deserialized in a cross-platform way.
Key Features
- Parse ASN.1 data into .NET types.
- Encode .NET types into ASN.1 format.
- Support for BER, CER, DER: Handles Basic Encoding Rules (BER), Canonical Encoding Rules (CER), and Distinguished Encoding Rules (DER).
How to Use
Parsing ASN.1 data:
using System.Formats.Asn1;
using System.Numerics;
// Sample ASN.1 encoded data (DER format)
byte[] asn1Data = [0x30, 0x09, 0x02, 0x01, 0x01, 0x02, 0x01, 0x02, 0x02, 0x01, 0x03];
// Create an AsnReader to parse the data
AsnReader reader = new(asn1Data, AsnEncodingRules.DER);
// Parse the sequence
AsnReader sequenceReader = reader.ReadSequence();
// Read integers from the sequence
BigInteger firstInt = sequenceReader.ReadInteger();
BigInteger secondInt = sequenceReader.ReadInteger();
BigInteger thirdInt = sequenceReader.ReadInteger();
Console.WriteLine($"First integer: {firstInt}");
Console.WriteLine($"Second integer: {secondInt}");
Console.WriteLine($"Third integer: {thirdInt}");
// First integer: 1
// Second integer: 2
// Third integer: 3
Decoding ASN.1 data using AsnDecoder
:
using System.Formats.Asn1;
using System.Numerics;
using System.Text;
// Sample ASN.1 encoded data
byte[] booleanData = [0x01, 0x01, 0xFF]; // BOOLEAN TRUE
byte[] integerData = [0x02, 0x01, 0x05]; // INTEGER 5
byte[] octetStringData = [0x04, 0x03, 0x41, 0x42, 0x43]; // OCTET STRING "ABC"
byte[] objectIdentifierData = [0x06, 0x03, 0x2A, 0x03, 0x04]; // OBJECT IDENTIFIER 1.2.3.4
byte[] utf8StringData = [0x0C, 0x05, 0x48, 0x65, 0x6C, 0x6C, 0x6F]; // UTF8String "Hello"
int bytesConsumed;
bool booleanValue = AsnDecoder.ReadBoolean(booleanData, AsnEncodingRules.DER, out bytesConsumed);
Console.WriteLine($"Decoded BOOLEAN value: {booleanValue}, Bytes consumed: {bytesConsumed}");
// Decoded BOOLEAN value: True, Bytes consumed: 3
BigInteger integerValue = AsnDecoder.ReadInteger(integerData, AsnEncodingRules.DER, out bytesConsumed);
Console.WriteLine($"Decoded INTEGER value: {integerValue}, Bytes consumed: {bytesConsumed}");
// Decoded INTEGER value: 5, Bytes consumed: 3
byte[] octetStringValue = AsnDecoder.ReadOctetString(octetStringData, AsnEncodingRules.DER, out bytesConsumed);
Console.WriteLine($"Decoded OCTET STRING value: {Encoding.ASCII.GetString(octetStringValue)}, Bytes consumed: {bytesConsumed}");
// Decoded OCTET STRING value: ABC, Bytes consumed: 5
string objectIdentifierValue = AsnDecoder.ReadObjectIdentifier(objectIdentifierData, AsnEncodingRules.DER, out bytesConsumed);
Console.WriteLine($"Decoded OBJECT IDENTIFIER value: {objectIdentifierValue}, Bytes consumed: {bytesConsumed}");
// Decoded OBJECT IDENTIFIER value: 1.2.3.4, Bytes consumed: 5
string utf8StringValue = AsnDecoder.ReadCharacterString(utf8StringData, AsnEncodingRules.DER, UniversalTagNumber.UTF8String, out bytesConsumed);
Console.WriteLine($"Decoded UTF8String value: {utf8StringValue}, Bytes consumed: {bytesConsumed}");
// Decoded UTF8String value: Hello, Bytes consumed: 7
Encoding ASN.1 data:
// Create an AsnWriter to encode data
AsnWriter writer = new(AsnEncodingRules.DER);
// Create a scope for the sequence
using (AsnWriter.Scope scope = writer.PushSequence())
{
// Write integers to the sequence
writer.WriteInteger(1);
writer.WriteInteger(2);
writer.WriteInteger(3);
}
// Get the encoded data
byte[] encodedData = writer.Encode();
Console.WriteLine($"Encoded ASN.1 Data: {BitConverter.ToString(encodedData)}");
// Encoded ASN.1 Data: 30-09-02-01-01-02-01-02-02-01-03
Main Types
The main types provided by this library are:
System.Formats.Asn1.AsnReader
System.Formats.Asn1.AsnWriter
System.Formats.Asn1.AsnDecoder
System.Formats.Asn1.AsnEncodingRules
Additional Documentation
- API documentation
- X.680 - Abstract Syntax Notation One (ASN.1): Specification of basic notation
- X.690 - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)
Feedback & Contributing
System.Formats.Asn1 is released as open source under the MIT license. Bug reports and contributions are welcome at the GitHub repository.
Product | Versions Compatible and additional computed target framework versions. |
---|---|
.NET | net5.0 was computed. net5.0-windows was computed. net6.0 was computed. net6.0-android was computed. net6.0-ios was computed. net6.0-maccatalyst was computed. net6.0-macos was computed. net6.0-tvos was computed. net6.0-windows was computed. net7.0 was computed. net7.0-android was computed. net7.0-ios was computed. net7.0-maccatalyst was computed. net7.0-macos was computed. net7.0-tvos was computed. net7.0-windows was computed. net8.0 is compatible. net8.0-android was computed. net8.0-browser was computed. net8.0-ios was computed. net8.0-maccatalyst was computed. net8.0-macos was computed. net8.0-tvos was computed. net8.0-windows was computed. net9.0 is compatible. |
.NET Core | netcoreapp2.0 was computed. netcoreapp2.1 was computed. netcoreapp2.2 was computed. netcoreapp3.0 was computed. netcoreapp3.1 was computed. |
.NET Standard | netstandard2.0 is compatible. netstandard2.1 was computed. |
.NET Framework | net461 was computed. net462 is compatible. net463 was computed. net47 was computed. net471 was computed. net472 was computed. net48 was computed. net481 was computed. |
MonoAndroid | monoandroid was computed. |
MonoMac | monomac was computed. |
MonoTouch | monotouch was computed. |
Tizen | tizen40 was computed. tizen60 was computed. |
Xamarin.iOS | xamarinios was computed. |
Xamarin.Mac | xamarinmac was computed. |
Xamarin.TVOS | xamarintvos was computed. |
Xamarin.WatchOS | xamarinwatchos was computed. |
-
.NETFramework 4.6.2
- System.Buffers (>= 4.5.1)
- System.Memory (>= 4.5.5)
- System.ValueTuple (>= 4.5.0)
-
.NETStandard 2.0
- System.Buffers (>= 4.5.1)
- System.Memory (>= 4.5.5)
-
net8.0
- No dependencies.
-
net9.0
- No dependencies.
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