Tls

A common Java SSL handshake failure stems from passing a null KeyManager array when initializing the SSLContext, which silently disables all certificate-based cipher suites. This post walks through the root cause and the four most frequent triggers behind the error.

Multiple CNs in a certificate Subject field are deprecated and cause compatibility failures. The SAN extension is the correct way to cover multiple names on a single certificate.

LDAP error 53 means the destination server is refusing a password change request. This post walks through the most common Active Directory requirements and policy settings that trigger the error.

Configure AES-NI accelerated encryption in transit for HDFS by setting the cipher suite and key length in hdfs-site.xml on both the NameNode/DataNode and client sides.

Learn how to check and interpret the kernel entropy pool on Linux, why low entropy can slow down SSL handshakes and SSH sessions, and what to do when the pool runs dry.

A quick reference for verifying AES-NI hardware acceleration across Java, OpenSSL, and the CPU itself. Includes benchmark commands to confirm the instruction set is actually being used.