System.Formats.Asn1 9.0.0-rc.2.24473.5
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.
Showing the top 20 packages that depend on System.Formats.Asn1.
Packages | Downloads |
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MailKit
MailKit is an Open Source cross-platform .NET mail-client library that is based on MimeKit and optimized for mobile devices.
Features include:
* HTTP, Socks4, Socks4a and Socks5 proxy support.
* SASL Authentication via ANONYMOUS, CRAM-MD5, DIGEST-MD5, LOGIN, NTLM, OAUTHBEARER, PLAIN, SCRAM-SHA-1, SCRAM-SHA-256, SCRAM-SHA-512 and XOAUTH2.
* A fully-cancellable SmtpClient with support for STARTTLS, 8BITMIME, BINARYMIME, ENHANCEDSTATUSCODES, SIZE, DSN, PIPELINING and SMTPUTF8.
* A fully-cancellable Pop3Client with support for STLS, UIDL, APOP, PIPELINING, UTF8, and LANG.
* A fully-cancellable ImapClient with support for ACL, QUOTA, LITERAL+, IDLE, NAMESPACE, ID, CHILDREN, LOGINDISABLED, STARTTLS, MULTIAPPEND, UNSELECT, UIDPLUS, CONDSTORE, ESEARCH, SASL-IR, COMPRESS, WITHIN, ENABLE, QRESYNC, SORT, THREAD, ANNOTATE, LIST-EXTENDED, ESORT, METADATA / METADATA-SERVER, NOTIFY, FILTERS, LIST-STATUS, SORT=DISPLAY, SPECIAL-USE / CREATE-SPECIAL-USE, SEARCH=FUZZY, MOVE, UTF8=ACCEPT / UTF8=ONLY, LITERAL-, APPENDLIMIT, STATUS=SIZE, OBJECTID, REPLACE, SAVEDATE, XLIST, and X-GM-EXT1.
* Client-side sorting and threading of messages (the Ordinal Subject and the Jamie Zawinski threading algorithms are supported).
* Asynchronous versions of all methods that hit the network.
* S/MIME, OpenPGP, DKIM and ARC support via MimeKit.
* Microsoft TNEF support via MimeKit.
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14 |
Oracle.ManagedDataAccess.Core
Oracle Data Provider for .NET (ODP.NET) Core is a multi-platform ADO.NET driver that provides fast data access from Microsoft .NET (Core) clients to Oracle databases. ODP.NET Core consists of a single 100% managed code dynamic-link library.
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Oracle.ManagedDataAccess.Core
Oracle Data Provider for .NET (ODP.NET) Core is an ADO.NET driver that provides fast data access from Microsoft .NET Core clients to Oracle databases. ODP.NET Core consists of a single 100% managed code dynamic-link library.
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System.Security.Cryptography.Cng
Provides cryptographic algorithm implementations and key management with Windows Cryptographic Next Generation API (CNG).
Commonly Used Types:
System.Security.Cryptography.RSACng
System.Security.Cryptography.ECDsaCng
System.Security.Cryptography.CngKey
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System.Security.Cryptography.Cng
Provides cryptographic algorithm implementations and key management with Windows Cryptographic Next Generation API (CNG).
Commonly Used Types:
System.Security.Cryptography.RSACng
System.Security.Cryptography.ECDsaCng
System.Security.Cryptography.CngKey
When using NuGet 3.x this package requires at least version 3.4.
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System.Security.Cryptography.OpenSsl
Provides cryptographic algorithm implementations and key management for non-Windows systems with OpenSSL.
Commonly Used Types:
System.Security.Cryptography.RSAOpenSsl
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8 |
System.Security.Cryptography.Pkcs
Provides support for PKCS and CMS algorithms.
Commonly Used Types:
System.Security.Cryptography.Pkcs.EnvelopedCms
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System.Security.Cryptography.Pkcs
Provides support for PKCS and CMS algorithms.
Commonly Used Types:
System.Security.Cryptography.Pkcs.EnvelopedCms
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7 |
System.Security.Cryptography.Pkcs
Provides support for PKCS and CMS algorithms.
Commonly Used Types:
System.Security.Cryptography.Pkcs.EnvelopedCms
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9 |
System.Security.Cryptography.Pkcs
Provides support for PKCS and CMS algorithms.
Commonly Used Types:
System.Security.Cryptography.Pkcs.EnvelopedCms
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11 |
System.Security.Cryptography.Pkcs
Provides support for PKCS and CMS algorithms.
Commonly Used Types:
System.Security.Cryptography.Pkcs.EnvelopedCms
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18 |
System.Security.Cryptography.Pkcs
Provides support for PKCS and CMS algorithms.
Commonly Used Types:
System.Security.Cryptography.Pkcs.EnvelopedCms
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61 |
System.Security.Cryptography.Pkcs
Provides support for PKCS and CMS algorithms.
Commonly Used Types:
System.Security.Cryptography.Pkcs.EnvelopedCms
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115 |
System.Security.Cryptography.Pkcs
Provides support for PKCS and CMS algorithms.
Commonly Used Types:
System.Security.Cryptography.Pkcs.EnvelopedCms
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214 |
System.Security.Cryptography.Pkcs
Provides support for PKCS and CMS algorithms.
Commonly Used Types:
System.Security.Cryptography.Pkcs.EnvelopedCms
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731 |
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.NET Framework 4.6.2
- System.Buffers (>= 4.5.1)
- System.Memory (>= 4.5.5)
- System.ValueTuple (>= 4.5.0)
.NET 8.0
- No dependencies.
.NET 9.0
- No dependencies.
.NET Standard 2.0
- System.Buffers (>= 4.5.1)
- System.Memory (>= 4.5.5)