Log legacy key import success/failure, CMS algorithm OIDs (content encryption + key transport), legacy key availability during decrypt attempts, and detailed error messages from both RSA-OAEP and RSAES-PKCS1-v1_5 decrypt paths.
Log legacy key import success/failure, CMS algorithm OIDs (content encryption + key transport), legacy key availability during decrypt attempts, and detailed error messages from both RSA-OAEP and RSAES-PKCS1-v1_5 decrypt paths.