Convert an RSA private key between PKCS#1 ("RSA PRIVATE KEY") and PKCS#8 ("PRIVATE KEY") — the format mismatch that trips up Java, Node, and some mail servers.
| PKCS#1 | Header reads -----BEGIN RSA PRIVATE KEY-----. This is the older, RSA-specific format — what OpenSSL produces by default with openssl genrsa. |
| PKCS#8 | Header reads -----BEGIN PRIVATE KEY----- (no "RSA"). This is the newer, algorithm-agnostic format Java, Node.js, and some mail servers specifically expect. |