SSL renegotiation and resumption

"Resumption and renegotiation are rather opposites. Resumption restarts a previous TLS session in a new TCP connection, using the same TLS parameters. Renegotiation continues an existing TLS session in the same TCP connection, but changes some of the parameters.
"


in Fiddler, check for the renegotiation_info field in the CONNECT requestsmethods


https://www.ssllabs.com/ssltest/


Secure Renegotiation Supported
Secure Client-Initiated Renegotiation Yes
Insecure Client-Initiated Renegotiation No

Session resumption (caching) Yes
Session resumption (tickets) No


check DisableRenegoOnClient link


https://www.salt.ky/disabling-tlsssl-renegotiation-in-configuration-manager-2012/ and https://support.microsoft.com/en-us/help/977377/microsoft-security-advisory-vulnerability-in-tls-ssl-could-allow-spoof

"Modify the key to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL\DisableRenegoOnClient | DWORD=0"



https://backstage.forgerock.com/knowledge/kb/article/a28022128 -Djdk.tls.rejectClientInitiatedRenegotiation=true


-Dsun.security.ssl.allowUnsafeRenegotiation=true ( see https://www.oracle.com/technetwork/java/javase/tlsreadme2-176330.html on why this is a bad idea)

Doc on Session Resumption https://spacehost.de/tls-session-resumption-caching-tickets/

jdk.tls.useExtendedMasterSecret=false
jdk.tls.allowLegacyResumption=true
jdk.tls.allowLegacyMasterSecret=true


Here more explanation on Resumption and Renegotiation



To understand JSSE in general read this guide https://docs.oracle.com/javase/8/docs/technotes/guides/security/jsse/JSSERefGuide.html