Convert string to java.Securtiy.Publickey in java

Question

In LDAP server, i stored my public key in string format. I have to compare the value retrieved from LDAP server and user certificate's public key.

From LDAP, I am retrieving "public key" in string format. By the following method I am getting the output in Publickey format.

   PublicKey pub = certificate.getPublicKey();

For example:

 public key which store and retrieved from ldap : 3082010a0282010100da7ce03ec4628dce29042f93787c6a70c0ee2c2911696519c2e2ca10526ae7c97c8b6f095c    755f8c5e9c6ab97937bc6b70cdda8791ecd4c23b53cc5a981ea4be54d849926812d54e1f0c1d8d209f1966a29d27    b3b38831fbbf4aa80cb942f419e82dbb7bdc43790edfe39093697b89f8c306825307a674e7ead0a9a204a7c4331b    bd91bb95450ad2b978e635754d93a463220951c0f686e745ab56f1546a97ae2d87f530bde91cd50c2227d8dc15dcfa83b5f8bfd9e0b220bd8c1aa79763eb9ba7fd7825068febc0eb5bcfaafb87f3cfd17e2cbbe2f34ca38afe41f4bbc2042fa60dcf523601c8e5814c9aa6b59a122f27bd8b41645d9e4d6354e6e73290a44b0203010001

By the getPublicKey(), the values which i got from the certificate:

***
Sun RSA public key, 2048 bits
  modulus: 27581529112434455235399395495614661533524412849635912113821287924504314523203618221111108554792991994769511573234800381771189010092150662628156212797633901233021643754113925752858789999673304383861033906601469425706410753965248401239420679412397865844085987446528705248999902851200983500329050023325120622391550261964890287105642353902616488504197743500423303718260297874452584758316112606373795219655154047474828562736482689611898639008146126941813294363625955891232168718045290340674469984492628450581693408065679439269743483807803383534881136917173883224245178115070348015851631285800664873321494327268193971774539
  public exponent: 65537

  System.out.println("the encoded thing is...."+pub.getEncoded()) is: [B@2c683bfc

  BASE64Encoder encoder = new BASE64Encoder();
  String s = encoder.encode(pub.getEncoded());
   o/p is
      MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA2nzgPsRijc4pBC+TeHxqcMDuLCkRaWUZ    wuLKEFJq58l8i28JXHVfjF6carl5N7xrcM3ah5Hs1MI7U8xamB6kvlTYSZJoEtVOHwwdjSCfGWai      nSezs4gx+79KqAy5QvQZ6C27e9xDeQ7f45CTaXuJ+MMGglMHpnTn6tCpogSnxDMbvZG7lUUK0rl4     5jV1TZOkYyIJUcD2hudFq1bxVGqXri2H9TC96RzVDCIn2NwV3PqDtfi/2eCyIL2MGqeXY+ubp/14JQaP68DrW8+q+4fzz9F+LLvi80yjiv5B9LvCBC+mDc9SNgHI5YFMmqa1mhIvJ72LQWRdnk1jVObnMpCkSwIDAQAB

Is there any way to compare both the values? String and Publickey

Answer 1

In ldap we can directly save our certificate instead of storing as integer values.

  In ldif file:
    dc: xxxx
    objectClass: yyyyy
    userCertificate;binary:< file:///path/to/certificate.der

like this we have to upload..:)

package to handle certificates:

 java.security.cert.X509Certificate 

Answer 2

i am storing the public key in the "string" format in LDAP server.

That's your first mistake. Don't do that. Store it as a byte array. String is not a container for binary data.

After that it's just a matter of comparing byte arrays, which you can do via Arrays.equals().

Answer 3

If the string that you got from LDAP server is of Base64encoded,

Encode you Public key object to String

---

1. Convert it to Byte array.

    byte array = pub.getEncoded();

2. Convert Byte array to String.

    BASE64Encoder encoder = new BASE64Encoder();
    string = encoder.encode(byte array);

Now you can compare the strings.