On Wed, Jul 26, 2017 at 09:21:43PM +0200, Michele Mase' wrote: > So, what should be the command line to use in order to obtain the same key? > openssl genrsa .... This creates keys in a legacy RSA algorithm-specific format. > openssl req -nodes -newkey rsa:2048 some_extra_parameters .... This creates keys in the preferred standard PKCS#8 format. You can use "openssl pkey" to read legacy RSA keys and output PKCS#8 keys. Or you can use "openssl genpkey" to generate PKCS#8 keys directly: # RSA (umask 077; openssl genpkey -algorithm rsa -pkeyopt rsa_keygen_bits:2048 -out key.pem) # ECDSA P-256 (umask 077; openssl genpkey -algorithm ec -pkeyopt ec_paramgen_curve:prime256v1 -pkeyopt ec_param_enc:named_curve -out key.pem) # ECDSA P-384 (umask 077; openssl genpkey -algorithm ec -pkeyopt ec_paramgen_curve:secp384r1 -pkeyopt ec_param_enc:named_curve -out key.pem) # ECDSA P-521 (umask 077; openssl genpkey -algorithm ec -pkeyopt ec_paramgen_curve:secp521r1 -pkeyopt ec_param_enc:named_curve -out key.pem) It is unfortunate that OpenSSL 1.0.2 does not accept curve name aliases for ec_paramgen_curve. Thus, for example, only "prime256v1" is accepted for P-256 and not any of its other names. I've not checked whether this is fixed in OpenSSL 1.1.0. -- Viktor. -- openssl-users mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-users