> From: openssl-dev On Behalf Of Nayna Jain > Sent: Wednesday, June 10, 2015 20:31 > If I have a pem file with private key in that, how do I check if that is RSA/DSA ? If it uses a "legacy" format, the BEGIN line specifies the algorithm -----BEGIN RSA PRIVATE KEY----- -----BEGIN DSA PRIVATE KEY----- -----BEGIN EC PRIVATE KEY----- If it uses either PKCS#8 format: if unencrypted there is an AlgorithmIdentifier field near the beginning that specifies the type of the key; if encrypted, you must first decrypt and the decrypted value contains the AlgorithmIdentifier. It's usually easier to let PEM_read_PrivateKey figure out for you. It reads all formats (encrypted only if you provide the correct passphrase) and returns an EVP_PKEY object whose type you can check with EVP_PKEY_type following the instructions on the manpage for EVP_PKEY_type.
