PKCS＃7バウンシーキャスルのSignedData問題

Question

私はそこにいる！

opensslで生成されたsmimeファイルに問題があります。私はopensslで生成されたsmime SignedDataパッケージを（BouncyCastleの助けを借りて）解析する必要があります。私は例を作成するには、このコマンドを使用：

openssl smime -sign -inkey Signer/signer_key.pem -in Signer/message.txt -text -out SMIME/signed.data -signer Signer/signer_cert.pem -certfile cacert.pem -outform smime 

問題は、私はプロセスでPKCS7のASN.1構造を記入して、ここで見つけることができ、標準で説明したアルゴリズムを適用する必要があるということです。 pkcs7 signedData

ASN.1構造は以下である：

SignedData ::= SEQUENCE { version Version, 
          digestAlgorithms DigestAlgorithmIdentifiers, 
          contentInfo ContentInfo, 
          certificates [0] IMPLICIT ExtendedCertificatesAndCertificates OPTIONAL, 
          crls [1] IMPLICIT CertificateRevocationLists OPTIONAL, 
          signerInfos SignerInfos } 

SignerInfo ::= SEQUENCE { version Version, 
          issuerAndSerialNumber IssuerAndSerialNumber, 
          digestAlgorithm DigestAlgorithmIdentifier, 
          authenticatedAttributes [0] IMPLICIT Attributes OPTIONAL, 
          digestEncryptionAlgorithm DigestEncryptionAlgorithmIdentifier, 
          encryptedDigest EncryptedDigest, 
          unauthenticatedAttributes [1] IMPLICIT Attributes OPTIONAL } 

問題は、署名の検証に起こります。標準では

となります。メッセージダイジェスト計算プロセスの結果は、signedAttrsフィールドが存在するかどうかによって異なります（ ）。フィールドが存在しない場合、結果は となり、上記の の内容のメッセージダイジェストになります。ただし、フィールドが存在する場合、signedAttrsフィールドに含まれるSignedAttrs値 の完全なDERエンコードのメッセージ が結果として生成されます。

私は平文を持っていますが、私はそのダイジェストを計算し、smimeファイルからencryptedDigestを読み込み、それを解読した結果と比較しています。それは属性がないと仮定します。しかし、どうやら、smimeパッケージに含まれる署名は、平文だけでなく、いくつかの属性に基づいて計算されることがわかります。私が知りたいのは、両方のダイジェストがSMIMEパッケージから読み取られたencryptedDigestフィールドと等しいように、必要な属性をcleantextに付加することで、この作業を行う方法です。

以下は私が使用しているメインです。単純化するために（膨大な量の）デバッグ部品を削除し、ポルトガル語のものを置き換えていくつかの英語のコメントを配置しました。私はそれを理解するのは非常に簡単だと思いますが、誰かがこのことに興味を持ったら私はコード全体を投稿できます。今

package signedData; 

import PKCS7.SignedData; 
import java.io.ByteArrayOutputStream; 
import java.io.FileInputStream; 
import java.io.ObjectOutputStream; 
import java.security.MessageDigest; 
import java.security.Security; 
import java.security.cert.CertStore; 
import java.security.cert.X509Certificate; 
import java.util.Arrays; 
import java.util.Collection; 
import java.util.Iterator; 
import java.util.Properties; 
import java.util.logging.Level; 
import java.util.logging.Logger; 
import javax.mail.Session; 
import javax.mail.internet.MimeMessage; 
import javax.mail.internet.MimeMultipart; 
import org.bouncycastle.cms.SignerInformation; 
import org.bouncycastle.cms.SignerInformationStore; 
import org.bouncycastle.mail.smime.SMIMESigned; 
import org.bouncycastle.util.Store; 
import sun.misc.BASE64Encoder; 


public class Main { 

    public static void main(String[] args) { 

     String ksFile = "Recipient/ks_recipient", ks_type = "JCEKS", key_alias = "recipient_pkcs12", cert_alias = "cacert", algorithm, provider = "BC"; 
     byte[] encrypted, encrypted2, decrypted, digest; 
     Cifra cipher; 
     Digest dgst; 
     X509Certificate cert; 
     Properties props; 
     Session session; 
     MimeMessage msg; 
     SMIMESigned signed; 
     SignerInformationStore signers; 
     SignerInformation s; 
     CertStore certs; 
     Collection c; 
     Iterator it, certIt; 
     ByteArrayOutputStream baos; 
     ObjectOutputStream oos; 


     if(args.length == 1) { 

      /** 
      * args[0] - SMIME's Path file 
      */ 


      try { 

       props = System.getProperties(); 
       session = Session.getDefaultInstance(props); 

       msg = new MimeMessage(session, new FileInputStream(args[0])); 
       signed = new SMIMESigned((MimeMultipart) msg.getContent()); 

       /* Putting information from various parties (contained in the SMIME package) in a Collection, in order to process the information from each individually */ 
       signers = signed.getSignerInfos(); 
       c = signers.getSigners(); 

       /* Read certificates from SMIME package */ 
       certs = (CertStore) signed.getCertificatesAndCRLs("Collection", provider); 


       /* Iterate through the signers */ 
       it = c.iterator(); 

       while(it.hasNext()) { 

        /* Isolate each signer information */ 
        s = (SignerInformation) it.next(); 

        Collection certCollection = certs.getCertificates(s.getSID()); 

        /* Iterate through this chain's certificates */ 
        certIt = certCollection.iterator(); 
        cert = (X509Certificate) certIt.next(); 


        /* Verify signer certificate with CA */ 
        if(Certificate_Handler.verifyCertificate(RW_KeyStore.getCertificate(ksFile, ks_type, cert_alias), cert, Security.getProvider(provider))) { 

         /* Read encryption algorithm identifier from SMIME package */ 
         algorithm = Gadgets.getBC_Algorithm(s.getEncryptionAlgOID()); 

         /* Read encrypted signature bytes */ 
         encrypted = s.toASN1Structure().getEncryptedDigest().getOctets(); 

         /* Create an instance of Digest, which is responsible for computing message digests */ 
         dgst = new Digest(Gadgets.getBC_DigestAlgorithm(s.getDigestAlgOID()), provider); 

         /* Specify the encryption algorithm */ 
         cipher = new Cifra(algorithm, provider); 

         // decrypt digest 
         decrypted = cipher.decifrar(encrypted2, cert.getPublicKey()); 


         /* Compute plaintext digest */ 
         digest = dgst.computeMessageDigest(((String) signed.getContent().getContent()).getBytes()); 

         /* Verify signature */ 
         if(MessageDigest.isEqual(decrypted, digest)) 
          System.out.println("check"); 
         else 
          System.out.println("fail"); 
        } 
        else 
         throw new Exception("Invalid Certificate"); 
       } 
      } 
      catch (Exception ex) { 

       Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex); 
      } 
     } 
     else 
      System.err.println("Invalid parameter number: " + args.length); 
    } 
} 

そして私が実際に使用しているものですSMIMEファイルの例は：

MIME-Version: 1.0 
Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg="sha1"; boundary="----BF337FE7381F86CE88DBE2ED7A24396E" 

This is an S/MIME signed message 

------BF337FE7381F86CE88DBE2ED7A24396E 
Content-Type: text/plain 

Executive Mansion, 
Washington, August 22, 1862. 

Hon. Horace Greeley: 
Dear Sir. 

I have just read yours of the 19th. addressed to myself through the New-York Tribune. If there be in it any statements, or assumptions of fact, which I may know to be erroneous, I do not, now and here, controvert them. If there be in it any inferences which I may believe to be falsely drawn, I do not now and here, argue against them. If there be perceptable in it an impatient and dictatorial tone, I waive it in deference to an old friend, whose heart I have always supposed to be right. 

As to the policy I "seem to be pursuing" as you say, I have not meant to leave any one in doubt. 

I would save the Union. I would save it the shortest way under the Constitution. The sooner the national authority can be restored; the nearer the Union will be "the Union as it was." If there be those who would not save the Union, unless they could at the same time save slavery, I do not agree with them. If there be those who would not save the Union unless they could at the same time destroy slavery, I do not agree with them. My paramount object in this struggle is to save the Union, and is not either to save or to destroy slavery. If I could save the Union without freeing any slave I would do it, and if I could save it by freeing all the slaves I would do it; and if I could save it by freeing some and leaving others alone I would also do that. What I do about slavery, and the colored race, I do because I believe it helps to save the Union; and what I forbear, I forbear because I do not believe it would help to save the Union. I shall do less whenever I shall believe what I am doing hurts the cause, and I shall do more whenever I shall believe doing more will help the cause. I shall try to correct errors when shown to be errors; and I shall adopt new views so fast as they shall appear to be true views. 

I have here stated my purpose according to my view of official duty; and I intend no modification of my oft-expressed personal wish that all men every where could be free. 

Yours, 
A. Lincoln. 
------BF337FE7381F86CE88DBE2ED7A24396E 
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Content-Transfer-Encoding: base64 
Content-Disposition: attachment; filename="smime.p7s" 

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------BF337FE7381F86CE88DBE2ED7A24396E-- 

Answer 1

私はそれを解決しました。 （pkcs7）標準では、ダイジェストを計算した後に補助構造（DigestInfo）が作成されます。

DigestInfo ::= SEQUENCE { digestAlgorithm DigestAlgorithmIdentifier, 
          digest Digest } 

私はSMIMEパッケージから読み込んEncryptedDigestを解読した後、結果はDigestInfoです。

それから私は、（各署名者用）signedAttributesのダイジェストの計算：

SignerInformation.getSignedAttributes() 

そして最後にDigestInfoに結果を配置します。それだけで、私は署名の妥当性をチェックします。 Et voila、それは働いている！これは本当に時間がかかる問題があったように、これは、私がやったのと同じ問題を抱えている人を助け

希望...