NAME
ecparam - EC parameter manipulation and generation SYNOPSIS
openssl ecparam [-inform DER|PEM] [-outform DER|PEM] [-in filename]
[-out filename] [-noout] [-text] [-C] [-check] [-name arg]
[-listcurves] [-convform arg] [-paramenc arg] [-noseed] [-rand
file(s)] [-genkey] [-engine id] DESCRIPTION This command is used to manipulate or generate EC parameter files. OPTIONS
-inform DER|PEM 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.
-outform DER|PEM This specifies the output format, the options have the same meaning
as the -inform option.
-in filename This specifies the input filename to read parameters from or standard input if this option is not specified.
-out filename 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.
-noout This option inhibits the output of the encoded version of the parameters.
-text This option prints out the EC parameters in human readable form.
-C This option converts the EC parameters into C code. The parameters can then be loaded by calling the getecgroupXXX() function.
-check Validate the elliptic curve parameters.
-name arg Use the EC parameters with the specified 'short' name. Use
-listcurves to get a list of all currently implemented EC parameters.
-listcurves If this options is specified ecparam will print out a list of all currently implemented EC parameters names and exit.
-convform This specifies how the points on the elliptic curve are converted into octet strings. Possible values are: compressed (the default value), uncompressed 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 OPENSSLECBINPTCOMP at compile time.
-paramenc arg This specifies how the elliptic curve parameters are encoded. Possible value are: namedcurve, i.e. the ec parameters are specified by a OID, or explicit where the ec parameters are explicitly given (see RFC 3279 for the definition of the EC parameters structures). The default value is namedcurve. Note the implicitlyCA alternative ,as specified in RFC 3279, is currently not implemented in OpenSSL.
-noseed This option inhibits that the 'seed' for the parameter generation is included in the ECParameters structure (see RFC 3279).
-genkey This option will generate a EC private key using the specified parameters.
-rand file(s) a file or files containing random data used to seed the random number generator, or an EGD socket (see RANDegd(3)). Multiple
files can be specified separated by a OS-dependent character. The
separator is ; for MS-Windows, , for OpenVMS, and : for all others.
-engine id specifying an engine (by its unique id string) will cause ecparam to attempt to obtain a functional reference to the specified engine, thus initialising it if needed. The engine will then be set as the default for all available algorithms. NOTES PEM format EC parameters use the header and footer lines:
-BEGIN EC PARAMETERS-
-END EC PARAMETERS- OpenSSL is currently not able to generate new groups and therefore ecparam can only create EC parameters from known (named) curves. EXAMPLES To create EC parameters with the group 'prime192v1':
openssl ecparam -out ecparam.pem -name prime192v1 To create EC parameters with explicit parameters:
openssl ecparam -out ecparam.pem -name prime192v1 -paramenc explicit To validate given EC parameters:
openssl ecparam -in ecparam.pem -check To create EC parameters and a private key:
openssl ecparam -out eckey.pem -name prime192v1 -genkey To change the point encoding to 'compressed':
openssl ecparam -in ecin.pem -out ecout.pem -convform compressed To print out the EC parameters to standard output:
openssl ecparam -in ecparam.pem -noout -text SEE ALSO ec(1), dsaparam(1) HISTORY The ecparam command was first introduced in OpenSSL 0.9.8. AUTHOR Nils Larsch for the OpenSSL project (http://www.openssl.org)
1.0.2k 2017-01-26 ECPARAM(1)