RSA Key Spec problem

I basically got this code right from the Tutorial at:

http://java.sun.com/docs/books/tutorial/security1.2/apisign/enhancements.html

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//"buf" is a byte array containing my RSA private key

java.security.spec.X509EncodedKeySpec spec =

new java.security.spec.X509EncodedKeySpec(buf);

java.security.KeyFactory key = java.security.KeyFactory.getInstance("RSA");

java.security.PrivateKey priv = key.generatePrivate(spec);

java.security.Signature sig = java.security.Signature.getInstance("RSA");

sig.initSign(priv);

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It blows up at the line:

java.security.PrivateKey priv = key.generatePrivate(spec);

with the error:

java.security.spec.InvalidKeySpecException: Key spec not RSA.

What Key spec can I use that works with RSA? TIA!

[896 byte] By [samt1] at [2007-9-26 1:52:10]