Problem 1) I try to change my skin in the launcher and it gives me the message "Successfully Uploaded Skin!" but when i go into a single player world it only shows as Alex

Problem 2) When i try to join a server in minecraft i receive the message "Internal Exception: java.lang.NoClassDefFoundError: Could not initalize class javax.crypto.JceSecurity"

I suspect these two problems are connected, because i have tried numerous ways of fixing both problems individually and some of the ways of troubleshooting involve knowing whether or not your custom skin shows up on servers.