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Starting with v2.5.2, the environment.build.sso.local.sharedSecret property also needs to be set to a non-empty value in {SSP_CONFIGDIR}/ssp-platform-config.properties. You can choose any value you like and it needn't be terribly complex: a banking-style PIN should be sufficient. If you are also using the LTI integration, a corresponding value needs to be set in SSP configuration. See the LTI provider documentation for more detail.
requireSecure
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