be a valid RSA private key in ASCII armor (.pem file), including line breaks
.new
.next
-with GnuTLS 3.6.0 or later, be a valid Ed25519 private key (same format as above)
+with GnuTLS 3.6.0 or OpenSSL 1.1.1 or later,
+be a valid Ed25519 private key (same format as above)
.wen
.next
start with a slash, in which case it is treated as a file that contains
.vitem &%$dkim_algo%&
The algorithm used. One of 'rsa-sha1' or 'rsa-sha256'.
.new
-If running under GnuTLS 3.6.0 or later, may also be 'ed25519-sha256'.
+If running under GnuTLS 3.6.0 or OpenSSL 1.1.1 or later,
+may also be 'ed25519-sha256'.
The "_CRYPTO_SIGN_ED25519" macro will be defined if support is present
for EC keys.
.wen