Python 与 C# 脚本输出相同的 base64 哈希

Question

我正在与拥有 API 的供应商合作。为了调用 API，他们要求我们对请求的整个 body 进行哈希处理，并将其添加到 Content-Digest 摘要 header 键中。 Content-Digest: SHA256=<digest>。他们为我们提供了一个 RSA 私钥以及一个用 C# 编写的 linq LINQPad 文件。此脚本输出进入 Content-Digest.

的 base64 编码哈希

问题是，我不知道任何 C#，我们将要使用此 API 的应用程序是用 Python 编写的。我正在寻找的是一种在 Python 脚本中输出完全相同格式的散列的方法。

这是他们提供的 C# 代码：

void Main()
{
    var payload = GetPayload();
    SignData(payload);
}
private void SignData(string payload)
{

    var keyFormatted = GetRSAKey();

    byte[] privateKeyInDER = Convert.FromBase64String(keyFormatted);

    var rsa = DecodeRSAPrivateKey(privateKeyInDER);

    var data = Encoding.Default.GetBytes(payload);
    using var hasher = new SHA512Managed();
    var signBytes = rsa.SignData(data, hasher);
    var computedSignature = Convert.ToBase64String(signBytes);
    computedSignature.Dump();
}

private static int GetIntegerSize(BinaryReader binary)
{
    var bt = binary.ReadByte();

    if (bt != 0x02)
    {
        return 0;
    }

    bt = binary.ReadByte();

    int count;
    if (bt == 0x81)
    {
        count = binary.ReadByte();
    }
    else if (bt == 0x82)
    {
        var highbyte = binary.ReadByte();
        var lowbyte = binary.ReadByte();
        byte[] modint = { lowbyte, highbyte, 0x00, 0x00 };
        count = BitConverter.ToInt32(modint, 0);
    }
    else
    {
        count = bt;
    }

    while (binary.ReadByte() == 0x00)
    {
        count--;
    }

    binary.BaseStream.Seek(-1, SeekOrigin.Current);

    return count;
}
public static RSACryptoServiceProvider DecodeRSAPrivateKey(byte[] privkey)
{
    byte[] MODULUS, E, D, P, Q, DP, DQ, IQ;

    // ---------  Set up stream to decode the asn.1 encoded RSA private key  ------
    MemoryStream mem = new MemoryStream(privkey);
    BinaryReader binr = new BinaryReader(mem);    //wrap Memory Stream with BinaryReader for easy reading
    try
    {
        var twobytes = binr.ReadUInt16();
        if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
        {
            binr.ReadByte();//advance 1 byte
        }
        else if (twobytes == 0x8230)
        {
            binr.ReadInt16();
        }       //advance 2 bytes
        else
        {
            return null;
        }

        twobytes = binr.ReadUInt16();
        if (twobytes != 0x0102) //version number
        {
            return null;
        }

        var bt = binr.ReadByte();
        if (bt != 0x00)
        {
            return null;
        }

        var elems = GetIntegerSize(binr);
        MODULUS = binr.ReadBytes(elems);

        elems = GetIntegerSize(binr);
        E = binr.ReadBytes(elems);

        elems = GetIntegerSize(binr);
        D = binr.ReadBytes(elems);

        elems = GetIntegerSize(binr);
        P = binr.ReadBytes(elems);

        elems = GetIntegerSize(binr);
        Q = binr.ReadBytes(elems);

        elems = GetIntegerSize(binr);
        DP = binr.ReadBytes(elems);

        elems = GetIntegerSize(binr);
        DQ = binr.ReadBytes(elems);

        elems = GetIntegerSize(binr);
        IQ = binr.ReadBytes(elems);

        // ------- create RSACryptoServiceProvider instance and initialize with private key -----
        RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
        RSAParameters RSAparams = new RSAParameters
        {
            Modulus = MODULUS,
            Exponent = E,
            D = D,
            P = P,
            Q = Q,
            DP = DP,
            DQ = DQ,
            InverseQ = IQ
        };
        RSA.ImportParameters(RSAparams);
        return RSA;
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.Message);
        return null;
    }
    finally
    {
        binr.Close();
    }
}
private string GetRSAKey() {
    return "private key";
}
private string GetPayload()
{
return @"{
""key"":""value"",
""key2"":{
    ""subkey"": true,}
    }";
}

它输出如下内容（344 个字符）： 15vgzyv8Cke3Mkkwc3ryAgDMmY6olRfvgLqNyfhfti2GAfLb6s/vgrWc1p5jlWgQHh37Ir7UYThXldspriBz5NPl+BSFIW2dxXTMO2NMpzgc/5fmFN2maJCgwzDP0aqupmUGrw/DZp8zMAKtxWqs+8TGQTDthAW+4Y8g0hoLYSTEIHwvbkBUCspWo4Qr0MXj86P1Gsu5DbQ4Fs23fbajPuZqRHTyYzeANvxnma9mm30CwLD6blnKOLa+xRVd6eeuHu+Hp+F8hl5xSJS0Bcse4K0ZKccDD6sm4KSX2vaNQeQQ45fIDYLRUXYckGifqu7nJLwHILEenxue10841IHleA==

我一直试图在 Python 中解决这个问题，这与我得到的最接近：

import hashlib
import base64
import hmac

key = '''
private key
'''
msg = '''
{"body to hash"}
'''
print((base64.b64encode(hmac.new(bytearray(key.upper(), "ASCII") , bytearray(msg,"ASCII") , hashlib.sha512).digest())).decode("ASCII"))

但是，这个 returns 哈希看起来像这样： 9dfgSdEzLEdGHze/SrYCSGVHurEvFabe3YgBSqKowxHb96UznenFFoeTDjx2dlk2B53qq9ISKVwv+xFBXMBePQ==

如有哪位大侠能提供帮助，将不胜感激！

Answer 1

我希望这能让你走上正确的方向。

请注意，我正在生成一个随机私钥，只是为了有一个工作示例。这会生成 344 个字符的输出，正如您所期望的那样：

b'Q9X/TOUJwJI101e5pXSg75zhNXk0VKA+cbbFJLF1OttmVIT3Pfa6xcpSvjE3ErW6SBKFlK+e/3AxNRr6h1TXhQQEtbMl9GmcBgJnvKOOWN8Ev40NvO+Ut7MEiHXDWZ888AXYe4sNMc61oUlj1d7wop0mZIL/+hMTQi9zVldfxWB/5PLLe/J3T451Ldj3XH5lL2AnesoCDgQTwWS20iCX8SE5JGh0pAJj+rImgyPinqvbf49uBq1DByKrAI5SVtB/6IoWpztyKKOfjy7QtcM71/CIWBrTAUi7TBXUlJ2si9s8alm+NUNKZZkWNS5SIkcZQrWPz+no6J9CGJt+JAXTRw=='

比较结果时请小心输入。在您的示例中，.NET 应用程序在有效负载末尾不包含新行 - 但是 python 应用程序包含。

from Crypto.Cipher import DES
from Crypto.PublicKey import RSA
from Crypto.Cipher import PKCS1_OAEP
from Crypto.Signature import PKCS1_v1_5
from Crypto.Hash import SHA512, SHA384, SHA256, SHA, MD5
from Crypto import Random
from base64 import b64encode, b64decode


def sign(message, priv_key):
    signer = PKCS1_v1_5.new(priv_key)        
    digest = SHA512.new()        
    digest.update(message)

    return signer.sign(digest)
    
# pem prefix and suffix in case it's not provided in your key
#pem_prefix = '-----BEGIN RSA PRIVATE KEY-----\n'
#pem_suffix = '\n-----END RSA PRIVATE KEY-----'

# here should be your key (without pem prefix and suffix)
#key = "thisisyourkey"

# assemble 
#key = '{}{}{}'.format(pem_prefix, key, pem_suffix)

# generate private key rsa object
#private = RSA.importKey(key)

# the following 3 lines are just to showcase a working key
random_generator = Random.new().read
keysize = 2048
private = RSA.generate(keysize, random_generator)

# payload to sign
msg = '''
{"body to hash"}
'''.encode("utf-8")

signature = sign(msg, private)
print(b64encode(signature))

Python 与 C# 脚本输出相同的 base64 哈希

Python base64 hash with same output as C# Script

c#

python

base64

sha256