Problem with public key transfer RSA, javaME, bouncy castle

Question

I am working on porting an instance messaging application from Java to JavaME, which also implements cryptography. The problem is that I want to send my public key to the server. The desktop client has this code for this job:

byte[] encoded_public_key=publick_key.getEncoded();

And the server has this code to retrieve the key:

EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(encoded_public_key);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey puKey = keyFactory.generatePublic(publicKeySpec);

Now I looked at the API for getEncoded, and it says that it returns a DER-encoded key form as a byte array (http://www.docjar.com/docs/api/sun/s...tml # getEncoded)

My implementation for JavaME was like this:

RSAPublicKeyStructure public_key_JAVAME=new RSAPublicKeyStructure(modulus,exponent);
byte[] DER_encoded_public_key_JAVAME=public_key_JAVAME.getDEREncoded();

//the getEncoded functions returns exact the same byte array.

However, when I try to get the JavaME generated DER key with server code, in other words, when I try to do this:

EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(DER_encoded_public_key_JAVAME);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey puKey = keyFactory.generatePublic(publicKeySpec);

I get

java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: IOException: algid parse error, not a sequence
at sun.security.rsa.RSAKeyFactory.engineGeneratePublic(RSAKeyFactory.java:188)
at java.security.KeyFactory.generatePublic(KeyFactory.java:304)

Caused by: java.security.InvalidKeyException: IOException: algid parse error, not a sequence
at sun.security.x509.X509Key.decode(X509Key.java:380)
at sun.security.x509.X509Key.decode(X509Key.java:386)
at sun.security.rsa.RSAPublicKeyImpl.<init>(RSAPublicKeyImpl.java:66)
at sun.security.rsa.RSAKeyFactory.generatePublic(RSAKeyFactory.java:281)
at sun.security.rsa.RSAKeyFactory.engineGeneratePublic(RSAKeyFactory.java:184)

. DER Java ( getencoded()) 162 , SAME- DER, JavaME , 140 . DER ? DER, .

?

---

, . , , subjectPublickeyInfo PublicKey bouncyCastle? :

ByteArrayInputStream bIn = new ByteArrayInputStream(RSApublickey.toString().getbytes()); SubjectPublicKeyInfo info = new SubjectPublicKeyInfo((ASN1Sequence)new ASN1InputStream(bIn).readObject());

. :

ByteArrayInputStream(RSApublicKeyStructure.getEncoded()); SubjectPublicKeyInfo info = new SubjectPublicKeyInfo((ASN1Sequence)new ASN1InputStream(bIn).readObject());

, , . , Subjectpublickeyinfo RSAkeyparameters? ( , , -, API- ).

, . .

Answer 1

DER- - . , DER-, , XML: , DER-/XML- .

RSAPublicKeyStructure.getEncoded() DER- ASN.1 RSAPublicKey:

RSAPublicKey ::= SEQUENCE {
  modulus INTEGER, -- n
  publicExponent INTEGER -- e 
}

, X509EncodedKeySpec DER- ASN.1 PublicKeyInfo:

PublicKeyInfo ::= SEQUENCE {
  algorithm AlgorithmIdentifier,
  PublicKey BIT STRING
}

PublicKeyInfo, BouncyCastle, ( GregS):

RSAPublicKeyStructure rsaPublicKey = /* ... */
AlgorithmIdentifier rsaEncryption = new AlgorithmIdentifier(PKCSObjectIdentifiers.rsaEncryption, null); 
SubjectPublicKeyInfo publicKeyInfo = new SubjectPublicKeyInfo(rsaEncryption, rsaPublicKey);
byte[] encodedPublicKeyInfo = publicKeyInfo.getEncoded();