openssl

Overview A software vendor publishes a new application package: along with a SHA-256 checksum. Before installing that package on a server, you want to answer: Is the file I downloaded exactly the same file the vendor published? Later, your own team distributes an internal … [Read more...] about OpenSSL dgst: Create Checksums and Verify Digital Signatures

Overview A TLS certificate can be: and still no longer be trustworthy. If the certificate's private key has been compromised or the certificate was issued incorrectly, the certificate authority can revoke it before its normal expiration date. One common way CAs publish that information … [Read more...] about OpenSSL crl: Check Certificate Revocation Lists and Revoked Certificates

Overview TLS protects information while it travels across a network, but sometimes a system administrator needs to protect the file itself. Consider a configuration export that must be transferred from one administrative environment to another. You want the recipient to be able to answer … [Read more...] about OpenSSL cms: Sign, Verify, Encrypt, and Decrypt Files

Overview TLS configuration often works perfectly until an administrator tightens the cipher configuration. Perhaps an old cipher is removed from a reverse proxy, web server, load balancer, or application server. Modern browsers continue working, but an older monitoring agent, Java application, … [Read more...] about OpenSSL ciphers: List, Filter, and Test TLS Cipher Suites