How can I construct a java.security.PublicKey object from a base64 encoded string?

java, rsa, security

Solution

Ok for grins ... try this

- base64 decode the key data to get a byte array (byte[])

- Create a new X509EncodedKeySpec using the byte array

- Get an instance of KeyFactory using KeyFactory.getInstance("RSA") assuming RSA here

- call the method generatePublic(KeySpec) with the X509EncodedKeySpec

- Result /should/ be a public key for your usage.

Problem

I have a bse64encoded string Public key from external source (Android Store) and I need to use it to verify signed content. How can I convert the string into an instance of the java.security.PublicKey interface. I am on Java 6 if that makes a difference. The key is (probably) generated using standard java lib and not bouncy castle (its from a remote team so I am not sure). Their sample code says to use Security.generatePublicKey(base64EncodedPublicKey); but the Security object in standard java has no such method.

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