openssl-ecparam, ecparam - EC parameter manipulation and generation
openssl ecparam [-help] [-inform DER|PEM] [-outform DER|PEM] [-in filename] [-out filename] [-noout] [-text] [-C] [-check] [-name arg] [-list_curves] [-conv_form arg] [-param_enc arg] [-no_seed] [-rand file...] [-writerand file] [-genkey] [-engine id]
This command is used to manipulate or generate EC parameter files.
Print out a usage message.
This specifies the input format. The DER option uses an ASN.1 DER encoded form compatible with RFC 3279 EcpkParameters. The PEM form is the default format: it consists of the DER format base64 encoded with additional header and footer lines.
This specifies the output format, the options have the same meaning and default as the -inform option.
This specifies the input filename to read parameters from or standard input if this option is not specified.
This specifies the output filename parameters to. Standard output is used if this option is not present. The output filename should not be the same as the input filename.
This option inhibits the output of the encoded version of the parameters.
This option prints out the EC parameters in human readable form.
This option converts the EC parameters into C code. The parameters can then be loaded by calling the get_ec_group_XXX() function.
Validate the elliptic curve parameters.
Use the EC parameters with the specified 'short' name. Use -list_curves to get a list of all currently implemented EC parameters.
If this options is specified ecparam will print out a list of all currently implemented EC parameters names and exit.
This specifies how the points on the elliptic curve are converted into octet strings. Possible values are: compressed, uncompressed (the default value) and hybrid. For more information regarding the point conversion forms please read the X9.62 standard. Note Due to patent issues the compressed option is disabled by default for binary curves and can be enabled by defining the preprocessor macro OPENSSL_EC_BIN_PT_COMP at compile time.
This specifies how the elliptic curve parameters are encoded. Possible value are: named_cu