In my quest for getting Java to open my Crypto++ RSA 1024-bit public key
I've noted that RSAFunction inherits from X509PublicKey.
X509PublicKey defines its method DEREncode as:
void DEREncode(BufferedTransformation &bt) const {
DERSequenceEncoder subjectPublicKeyInfo(bt);
DERSequenceEncoder algorithm(subjectPublicKeyInfo);
GetAlgorithmID().DEREncode(algorithm);
DEREncodeAlgorithmParameters(algorithm);
algorithm.MessageEnd();
DERGeneralEncoder subjectPublicKey(
subjectPublicKeyInfo, BIT_STRING);
subjectPublicKey.Put(0); // unused bits
DEREncodeKey(subjectPublicKey);
subjectPublicKey.MessageEnd();
subjectPublicKeyInfo.MessageEnd();
}
Now, according to ASN1 syntax X509 public keys should be represented as:
SubjectPublicKeyInfo ::= SEQUENCE {
algorithm AlgorithmIdentifier,
subjectPublicKey BIT STRING }
So my question is: in the code above why are the algorithm parameters included?
And whats the extra 'unused bits' for? Now, admittedly even though I have a
modicum of understanding of Cryptography - my knowledge of PK standards is
practically
non existent so I apologise in advance for any misunderstandings on my part.
I'm just trying to get Java to import my friggin key!! Java throws a BER Decode
error, is this normal?
To decode a DER encoded key with a BER decoding algorithm? I'm guessing it is.
Any comments on my rantings above?
Cheers (again),
Jim
--
James Vanns BSc (Hons) MCP
Linux Systems Administrator
Software Engineer (Linux / C & C++)
Canterbury Christ Church University College
Public Key: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x24045370
