如何手动验证DKIM正文哈希？

Question

这是自动转发的电子邮件。 我试图根据rfc5322验证bh字段。 但是收到的sha256哈希值与此值不匹配。 邮件正文是：用于转发邮件 有没有正确验证bh =字段的建议？ 我已经包含了一些示例标题字段数据。请做解释（轻松）规范程序

    DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1516798995;
        s=jan2017; d=headsup.co.in; i=sender@headsup.co.in;
        h=Date:From:To:Message-Id:Subject:MIME-Version:Content-Type; l=627;
        bh=ODw8icD/S+4UGcXgR4ocNpxXDh4PolWtd1IUXjh0AUs=;
        b=G2vTZ+uQ+krw49l+4aMnaeZjUvAJXPPRA8bvOhs3XZNbd2Ng+odB/F5PI3tRpdhr
        C0CJA5KPv4VncP2V1PjNdkgKLjs1eTzLSaqmPjhhQDc8mWQRT0rzcPP3V9v6BeXF987
        54Zns/QWtR+RbSacFXvUjyBEOlaWUVAmaVcqw5S8=

    //Message: for forwarded mail
  //Example Data
    Date: Wed, 24 Jan 2018 18:33:08 +0530
    From: sender <sender@headsup.co.in>
    To: "receiver" <receiver@gmail.com>
    Message-Id: <1612843d10d.d305604a24030.1212846966506749871@headsup.co.in>
    Subject: Test Arc Seal
    MIME-Version: 1.0
    Content-Type: multipart/alternative; 
        boundary="----=_Part_76205_1329960269.1516798988558"
    X-Priority: Medium  






//Cannonicalization code (relaxed)
package canonicalization;

import java.io.IOException;



public class Canonicalization {


        public String canonicalizeHeader(String name, String value) {
            name = name.trim().toLowerCase();
            value = value.replaceAll("\\s+", " ").trim();
            return name + ":" + value;
        }

        public String canonicalizeBody(String body) {

            if (body == null || "".equals(body)) {
                return "\r\n";
            }

            body = body.replaceAll("[ \\t\\x0B\\f]+", " ");
            body = body.replaceAll(" \r\n", "\r\n");

            // The body must end with \r\n
            if (!body.endsWith("\r\n")) {
                return body + "\r\n";
            }

            // Remove trailing empty lines ...
            while (body.endsWith("\r\n\r\n")) {
                body = body.substring(0, body.length() - 2);
            }

            return body;

        }
        public static void main(String[] args) {
            Canonicalization obj=new Canonicalization();
            System.out.println(obj.canonicalizeHeader("Date"," Wed, 24 Jan 2018 18:33:08 +0530"));
            System.out.println(obj.canonicalizeHeader("From"," sender <sender@headsup.co.in>"));
            System.out.println(obj.canonicalizeHeader("To"," \"receiver\" <receiver@gmail.com>"));

            System.out.println(obj.canonicalizeBody("for forwarded mail"));

        } 
}

Answer 1

您没有提供任何代码来说明您是如何尝试验证正文哈希的，但很可能您错误地规范了输入到哈希函数的输入。

Answer 2

该代码适用于以纯文本格式发送的电子邮件（Content-Type：text / plain;）

但默认情况下，电子邮件是通过RTF格式发送的（内容类型：multipart / alternative;），因此正文哈希值不匹配