Question

我目前正在尝试使用Java Security API和BouncyCastle生成主题哈希。

这是我在使用Openssl库时所做的事情：

openssl x509 -in  /Users/Sn0wfreezeDev/Downloads/Test.pem -hash

这会产生一个短的8位哈希 1817886a

这是我的Java代码

X509Certificate cert = CertManager.getCertificate(number, c);  
MessageDigest sha1 = MessageDigest.getInstance("SHA1");
System.out.println("  Subject " + cert.getSubjectDN());
System.out.println("   Issuer  " + cert.getIssuerDN());
sha1.update(cert.getSubjectDN().getName().getBytes());
String hexString =  bytesToHex(sha1.digest());
System.out.println("   sha1    " + hexString);
System.out.println();

Answer 1

这会产生一个短的8位数哈希1817886a

OpenSSL有两种形式：

$ cd openssl-1.0.2-src
$ grep -R X509_subject_name_hash *
...
crypto/x509/x509.h:unsigned long X509_subject_name_hash(X509 *x);
crypto/x509/x509.h:unsigned long X509_subject_name_hash_old(X509 *x);
crypto/x509/x509_cmp.c:unsigned long X509_subject_name_hash(X509 *x)
crypto/x509/x509_cmp.c:unsigned long X509_subject_name_hash_old(X509 *x)
...

在Java中生成X509Certificate的主题哈希...

以下是crypto/x509/x509_cmp.c的来源：

unsigned long X509_subject_name_hash(X509 *x)
{
    return (X509_NAME_hash(x->cert_info->subject));
}

#ifndef OPENSSL_NO_MD5
unsigned long X509_subject_name_hash_old(X509 *x)
{
    return (X509_NAME_hash_old(x->cert_info->subject));
}
#endif

最后：

unsigned long X509_NAME_hash(X509_NAME *x)
{
    unsigned long ret = 0;
    unsigned char md[SHA_DIGEST_LENGTH];

    /* Make sure X509_NAME structure contains valid cached encoding */
    i2d_X509_NAME(x, NULL);
    if (!EVP_Digest(x->canon_enc, x->canon_enclen, md, NULL, EVP_sha1(),
                    NULL))
        return 0;

    ret = (((unsigned long)md[0]) | ((unsigned long)md[1] << 8L) |
           ((unsigned long)md[2] << 16L) | ((unsigned long)md[3] << 24L)
        ) & 0xffffffffL;
    return (ret);
}

#ifndef OPENSSL_NO_MD5
unsigned long X509_NAME_hash_old(X509_NAME *x)
{
    EVP_MD_CTX md_ctx;
    unsigned long ret = 0;
    unsigned char md[16];

    /* Make sure X509_NAME structure contains valid cached encoding */
    i2d_X509_NAME(x, NULL);
    EVP_MD_CTX_init(&md_ctx);
    EVP_MD_CTX_set_flags(&md_ctx, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
    if (EVP_DigestInit_ex(&md_ctx, EVP_md5(), NULL)
        && EVP_DigestUpdate(&md_ctx, x->bytes->data, x->bytes->length)
        && EVP_DigestFinal_ex(&md_ctx, md, NULL))
        ret = (((unsigned long)md[0]) | ((unsigned long)md[1] << 8L) |
               ((unsigned long)md[2] << 16L) | ((unsigned long)md[3] << 24L)
            ) & 0xffffffffL;
    EVP_MD_CTX_cleanup(&md_ctx);

    return (ret);
}
#endif

i2d_X509_NAME使用RFC 2459（和其他地方）将X509_NAME编码为标准表示。例如，它用于证书主题和发行人名称。

您可以使用openssl x509 -in <cert> -text -noout等命令查看OpenSSL用于名称字符串的内容。它看起来与C=US, ST=California, L=Mountain View, O=Google Inc, CN=www.google.com类似（取自Google证书）。

在Java中生成X509Certificate的主题哈希...

在大图中，您正在生成Subject的Distinguished Name字符串的哈希并返回unsigned long。 unsigned long实际上是一个截断的哈希值。

X509_subject_name_hash使用SHA-1，X509_subject_name_hash_old使用MD5。

（评论）......他们如何使用sha1哈希来生成短哈希

OpenSSL提供截断哈希的十六进制编码。整个哈希值在md中。 md将是16个字节（MD5）或20个字节（SHA-1）。

通过选择字节[0,3]以及md[0]，md[1]，md[2]和md[3]上的位操作进行截断。

8位数字来自16位字节的十六进制编码。

用Java生成X509Certificate的主题哈希

1 个答案: