从ECDSA签名签名c＃提取R和S

发布于 2025-01-30 23:35:55 字数 125 浏览 4 评论 0原文

我正在使用.NET 5中的signedxml类用于使用ECDA生成签名我需要R和S的价值，但我无法提取它，另一个问题是签名长度。我的签名总是64个字节，但ECDSA签名长度为71 而且我不知道为什么这段时间会改变。请帮助我提取R和S

原文

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

剩余の解释 2025-02-06 23:35:55

将ECDA签名从ASN.1/der转换为p1363（r | s）格式时，必须考虑以下内容：

以ASN.1/der格式r和s包含为签名， Big Endian阵列，以p1363格式为 unsigned ，Big Endian Arrays。
在ASN.1/der格式中，将r和s作为最小尺寸阵列包含，在p1363中，两者都填充到其最大尺寸（发电机点的顺序长度）中带领先的0x00值。示例：对于NIST P-256，R和S的最大尺寸为32字节。

使用asnreader class class

using System.Formats.Asn1;
...
public static byte[] DERtoP1363(byte[] derSignature, int maxSize)
{
    AsnReader sequence = new AsnReader(derSignature, AsnEncodingRules.DER).ReadSequence();
    byte[] rBytes = sequence.ReadInteger().ToByteArray(true, true); // convert to unsigned, big endian
    byte[] sBytes = sequence.ReadInteger().ToByteArray(true, true); // convert to unsigned, big endian
    byte[] rsBytes = new byte[2 * maxSize];
    Buffer.BlockCopy(rBytes, 0, rsBytes, maxSize - rBytes.Length, rBytes.Length);     // resize to maximum size
    Buffer.BlockCopy(sBytes, 0, rsBytes, 2 * maxSize - sBytes.Length, sBytes.Length); // resize to maximum size
    return rsBytes;
}

class

自从.NET 5。对于完整性以来，可以类实现。 org.bouncycastle.asn1名称空间）。为此，dertop1363（）中的前三行必须由以下方式代替：

Asn1Sequence sequence = Asn1Sequence.GetInstance(derSignature);
byte[] rBytes = DerInteger.GetInstance(sequence[0]).PositiveValue.ToByteArrayUnsigned();
byte[] sBytes = DerInteger.GetInstance(sequence[1]).PositiveValue.ToByteArrayUnsigned();

When converting the ECDSA signature from ASN.1/DER to P1363 (r|s) format, the following must be taken into account:

In ASN.1/DER format r and s are contained as signed, big endian arrays, in P1363 format as unsigned, big endian arrays.
In ASN.1/DER format r and s are included as minimal sized arrays, in P1363 both are padded to their maximum size (length of the order of the generator point) with leading 0x00 values. Example: For NIST P-256, the maximum size of r and s is 32 bytes each.

Possible implementation with .NET 5+ using the AsnReader class:

using System.Formats.Asn1;
...
public static byte[] DERtoP1363(byte[] derSignature, int maxSize)
{
    AsnReader sequence = new AsnReader(derSignature, AsnEncodingRules.DER).ReadSequence();
    byte[] rBytes = sequence.ReadInteger().ToByteArray(true, true); // convert to unsigned, big endian
    byte[] sBytes = sequence.ReadInteger().ToByteArray(true, true); // convert to unsigned, big endian
    byte[] rsBytes = new byte[2 * maxSize];
    Buffer.BlockCopy(rBytes, 0, rsBytes, maxSize - rBytes.Length, rBytes.Length);     // resize to maximum size
    Buffer.BlockCopy(sBytes, 0, rsBytes, 2 * maxSize - sBytes.Length, sBytes.Length); // resize to maximum size
    return rsBytes;
}

AsnReader is available since .NET 5.

For completeness: In other .NET versions BouncyCastle can be applied (using classes from the Org.BouncyCastle.Asn1 namespace). For this, the first three lines in DERtoP1363() must by replaced by:

Asn1Sequence sequence = Asn1Sequence.GetInstance(derSignature);
byte[] rBytes = DerInteger.GetInstance(sequence[0]).PositiveValue.ToByteArrayUnsigned();
byte[] sBytes = DerInteger.GetInstance(sequence[1]).PositiveValue.ToByteArrayUnsigned();

回复收藏 0 原文

~没有更多了~