Java 1.7 Subject Hash of X.509 Certificate OpenSSL 1.0+ Compatible

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轮回少年 2021-02-11 01:58

I\'ve been struggling with this for a couple of days. I\'m working on a Java 1.7 app running in an embedded Linux environment. OpenSSL is not available and I don\'t have control

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予麋鹿 (楼主)

2021-02-11 02:53

Several answers here were given, they were extremely helpful for me, I claim them to be incomplete (wrong). Forget the canoncial format created by Java, it is not compatible with the one created by OpenSSL and it cannot be used to recode to OpenSSL format. Please note, there is no standard for a "canonical" format. (I can go in detail if required).

My code is based on the RFC's Name definition definition (not covered by other answers) and the OpenSSL code (not fully covered by other answers).

I have tested my coded against:

https://curl.haxx.se/ca/cacert.pem
https://www.quovadisglobal.com/download-roots-crl/
https://new.siemens.com/global/en/general/legal/ca-certificates.html

Verification in C:

#include 
#include 
#include 


int main(void) {
  ASN1_STRING * tugra_asn1 = ASN1_STRING_type_new(V_ASN1_UTF8STRING);
  /*char *tugra = "E-Tuğra EBG Bilişim Teknolojileri ve Hizmetleri A.Ş.";
   */
  char *wikipedia = "Википедия";
  ASN1_STRING_set(tugra_asn1, tugra, -1);
  printf("ASN1_STRING_length: %d\n", ASN1_STRING_length(tugra_asn1));
  ASN1_STRING * tugra_asn1_canon = ASN1_STRING_new();
  int ret = asn1_string_canon(tugra_asn1_canon, tugra_asn1);
  printf("ret: %d\n", ret);
  printf("ASN1_STRING_length: %d\n", ASN1_STRING_length(tugra_asn1_canon));
  const unsigned char * data = ASN1_STRING_data(tugra_asn1_canon);
  printf("ASN1_STRING_canon: %s\n", data);

  printf("ASN1_tag2str: %s\n", ASN1_tag2str(ASN1_STRING_type(tugra_asn1)));
  return 0;

}

The code works with OpenSSL 1.0.2+, but needs to be modified because asn1_string_canon is static. Remove and recompile OpenSSL.

Now the Java code:

    byte[] encoded = subject.getEncoded();

    Asn1Sequence asn1Name = (Asn1Sequence) Asn1.decode(encoded);
    ByteBuffer recoded = ByteBuffer.allocate(asn1Name.getContainer().getBodyLength());

    // Based on https://github.com/openssl/openssl/blob/852c2ed260860b6b85c84f9fe96fb4d23d49c9f2/crypto/x509/x_name.c#L296-L306
    // We only need the sequence elements
    for (Asn1Type asn1type0 : asn1Name.getValue()) {
      Asn1Set asn1Rdn = (Asn1Set) asn1type0;
      for (Asn1Type asn1type1 : asn1Rdn.getValue()) {
        Asn1Sequence asn1Ava = (Asn1Sequence) asn1type1;
        List asn1AvaTV = asn1Ava.getValue();
        Asn1ObjectIdentifier asn1AttrType = (Asn1ObjectIdentifier) asn1AvaTV.get(0);
        Asn1Type asn1AttrValue = asn1AvaTV.get(1);
        UniversalTag valueTag = asn1AttrValue.tag().universalTag();
        switch(valueTag) {
        case UTF8_STRING:
        case BMP_STRING:
        case UNIVERSAL_STRING:
        case PRINTABLE_STRING:
        case T61_STRING:
        case IA5_STRING:
        case VISIBLE_STRING:
          Asn1String asn1AttrValueString = (Asn1String) asn1AttrValue;
          String string = asn1AttrValueString.getValue();
          string = string.replaceAll("^\\s+|\\s+$", "").replaceAll("\\s+", " ");
          char[] chars = string.toCharArray();
          for (int i = 0; i < chars.length; i++) {
            char c = chars[i];
            if (c >= 'A' && c <= 'Z')
              chars[i] = Character.toLowerCase(c);
          }
          String utf8String = new String(chars);
          Asn1Utf8String asn1Utf8Sring = new Asn1Utf8String(utf8String);
          asn1AttrValue = asn1Utf8Sring;

          asn1Ava.clear();
          asn1Ava.addItem(asn1AttrType);
          asn1Ava.addItem(asn1AttrValue);
          break;
        default:
          // leave as-is
          break;
        }
      }

      byte[] asn1RdnDer = asn1Rdn.encode();

      // Concat for hash
      if (recoded.position() + asn1RdnDer.length > recoded.capacity()) {
        ByteBuffer tmp = recoded;
        recoded = ByteBuffer.allocate(tmp.position() + asn1RdnDer.length);
        tmp.flip();
        recoded.put(tmp);
      }
      recoded.put(asn1RdnDer);
    }

    recoded.flip();

    try {
      MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
      byte[] hash = sha1.digest(Arrays.copyOf(recoded.array(), recoded.remaining()));

      int truncHash = (((hash[0] & 0xff)) | (((hash[1] & 0xff) << 8))
          | (((hash[2] & 0xff) << 16)) | (((hash[3] & 0xff) << 24)));
      System.out.printf("subject hash: %08x%n", truncHash);
    } catch (NoSuchAlgorithmException e) {
      // Should not happen for SHA-1
    }

You will need:


  org.apache.kerby
  kerby-asn1
  2.0.1-SNAPSHOT

A very lightweight ASN.1 library (60 kB), way less than BC.

Here is a self-signed cert with UTF-8 bytes as well as a lot of whitespace:

Subject: emailAddress=MICHAEL-O@EXAMPLE.COM,CN=\ \ \ Michael-O Certificate Authority\ \ \ \ ,OU=Example Corp.\ \ \ \ ,O=\ \ Википедию Википедию\ \ \ \ ,L=\ \ BÖR l iN\ \ \ \ ,ST=\ \ Bör lin\ \ \ ,C=DE

Fingerprint (SHA-256): F0:04:0D:38:8A:E5:93:A8:51:1D:06:3E:96:8F:44:29:29:F2:2D:57:A1:5F:7B:CB:F9:F4:EE:98:5B:A8:50:CA

Subject Hash: 5ba4b7de

Properly canonicalized subject X.509 name from my Java code in DER: MIHMMQswCQYDVQQGDAJkZTERMA8GA1UECAwIYsO2ciBsaW4xEjAQBgNVBAcMCWLDlnIgbCBpbjEuMCwGA1UECgwl0JLQuNC60LjQv9C10LTQuNGOINCS0LjQutC40L/QtdC00LjRjjEWMBQGA1UECwwNZXhhbXBsZSBjb3JwLjEoMCYGA1UEAwwfbWljaGFlbC1vIGNlcnRpZmljYXRlIGF1dGhvcml0eTEkMCIGCSqGSIb3DQEJAQwVbWljaGFlbC1vQGV4YW1wbGUuY29t

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