Randhana https://randhana.com/blog Thoughtful work. Real impact. en-us pulathisi.kariyawasam@gmail.com (Pulathisi Kariyawasam) pulathisi.kariyawasam@gmail.com (Pulathisi Kariyawasam) Sun, 01 Nov 2026 00:00:00 GMT https://randhana.com/blog/when-a-cas-private-key-was-just-the-number-4-emudhra-incident When a CA's Private Key Was Just the Number 4: The eMudhra Incident, Reproduced by Hand https://randhana.com/blog/when-a-cas-private-key-was-just-the-number-4-emudhra-incident eMudhra's certificate keys got compromised in October 2026 - and one of them was literally the number 4. I take what I learned writing about TLS and Diffie-Hellman and use it to reproduce the weak key myself, step by step. Sun, 01 Nov 2026 00:00:00 GMT pulathisi.kariyawasam@gmail.com (Pulathisi Kariyawasam) securitytlscertificatescryptographyecdsapkihands-on