Class ECDsaEncoding

Class with helper methods to encode and decode ECDSA signatures

Inheritance

Object

ECDsaEncoding

Inherited Members

Object.ToString()

Object.Equals(Object)

Object.Equals(Object, Object)

Object.ReferenceEquals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Namespace: Lacuna.Pki.Asn1

Assembly: Lacuna.Pki.dll

Syntax

public static class ECDsaEncoding

Remarks

RFC 6979 -- Deterministic Usage of the Digital Signature Algorithm (DSA) and Elliptic Curve Digital Signature Algorithm (ECDSA) -- does not specify an encoding for ECDSA signatures. Section 2.4 states:

The pair (r, s) is the signature. How a signature is to be encoded is not covered by the DSA and ECDSA standards themselves; a common way is to use a DER-encoded ASN.1 structure (a SEQUENCE of two INTEGERs, for r and s, in that order).

Therefore, each protocol is responsible for defining the encoding of ECDSA signatures.

This class contains methods for encoding and decoding ECDSA signatures between protocol-specific encodings from/to .NET's native representation of signatures.

Methods

DecodeX509Signature(Byte[], Int32)

Decodes an ECDSA signature encoded according to the X.509 standard into .NET's representation of an ECDSA signature

Declaration

public static byte[] DecodeX509Signature(byte[] berSignature, int qLength)

Parameters

Type	Name	Description
Byte[]	berSignature	The X.509 encoded ECDSA signature
Int32	qLength	Length of the EC field, in bytes

Returns

Type	Description
Byte[]	The ECDSA signature encoded in .NET's native encoding

Remarks

If you only have the length in bits of the key, use the method GetFieldLength to get the length in bytes of the field and pass it on the qLength parameter.

EncodeX509Signature(Byte[])

Encodes an ECDSA signature encoded in .NET's native encoding to X.509 encoding

Declaration

public static byte[] EncodeX509Signature(byte[] netSignature)

Parameters

Type	Name	Description
Byte[]	netSignature	The ECDSA signature encoded in .NET's native encoding

Returns

Type	Description
Byte[]	The ECDSA signature encoded in X.509 encoding

GetFieldLength(Int32)

Declaration

public static int GetFieldLength(int keyBitSize)

Parameters

Type	Name	Description
Int32	keyBitSize

Returns

Type	Description
Int32

TryDecodeX509Signature(Byte[], Int32, out Byte[])

Decodes an ECDSA signature encoded according to the X.509 standard into .NET's representation of an ECDSA signature. A return value indicates whether the conversion succeeded.

Declaration

public static bool TryDecodeX509Signature(byte[] berSignature, int qLength, out byte[] netSignature)

Parameters

Type	Name	Description
Byte[]	berSignature	The X.509 encoded ECDSA signature
Int32	qLength	Length of the EC field, in bytes
Byte[]	netSignature	The ECDSA signature encoded in .NET's native encoding

Returns

Type	Description
Boolean	true if berSignature was decoded successfully; otherwise, false.

Remarks

If you only have the length in bits of the key, use the method GetFieldLength to get the length in bytes of the field and pass it on the qLength parameter.