{ "content": [ { "type": "text", "text": "# OPENSSL-ECPARAM(1SSL) (man)\n\n**Summary:** openssl-ecparam - EC parameter manipulation and generation\n\n**Synopsis:** openssl ecparam [-help] [-inform DER|PEM] [-outform DER|PEM] [-in filename] [-out filename]\n[-noout] [-text] [-check] [-checknamed] [-name arg] [-listcurves] [-convform arg]\n[-paramenc arg] [-noseed] [-genkey] [-engine id] [-rand files] [-writerand file] [-provider\nname] [-provider-path path] [-propquery propq]\n\n## Flags\n\n| Flag | Long | Arg | Description |\n|------|------|-----|-------------|\n| — | — | — | Print out a usage message. |\n| — | — | — | The EC parameters input format; unspecified by default. See openssl-format-options(1) for details. |\n| — | — | — | The EC parameters output format; the default is PEM. See openssl-format-options(1) for details. Parameters are encoded a |\n| — | — | — | This specifies the input filename to read parameters from or standard input if this option is not specified. |\n| — | — | — | This specifies the output filename parameters to. Standard output is used if this option is not present. The output file |\n| — | — | — | This option inhibits the output of the encoded version of the parameters. |\n| — | — | — | This option prints out the EC parameters in human readable form. |\n| — | — | — | Validate the elliptic curve parameters. |\n| — | — | — | Validate the elliptic name curve parameters by checking if the curve parameters match any built-in curves. |\n| — | — | — | Use the EC parameters with the specified 'short' name. Use -listcurves to get a list of all currently implemented EC par |\n| — | — | — | Print out a list of all currently implemented EC parameters names and exit. |\n| — | — | — | This specifies how the points on the elliptic curve are converted into octet strings. Possible values are: compressed, u |\n| — | — | — | This specifies how the elliptic curve parameters are encoded. Possible value are: namedcurve, i.e. the ec parameters are |\n| — | — | — | This option inhibits that the 'seed' for the parameter generation is included in the ECParameters structure (see RFC 327 |\n| — | — | — | This option will generate an EC private key using the specified parameters. |\n| — | — | — | See \"Engine Options\" in openssl(1). This option is deprecated. |\n| — | — | — | See \"Random State Options\" in openssl(1) for details. |\n| — | — | — | |\n| — | — | — | |\n| — | — | — | See \"Provider Options\" in openssl(1), provider(7), and property(7). The openssl-genpkey(1) and openssl-pkeyparam(1) comm |\n\n## Examples\n\n- `The documentation for the openssl-genpkey(1) and openssl-pkeyparam(1) commands contains`\n- `examples equivalent to the ones listed here.`\n- `To create EC parameters with the group 'prime192v1':`\n- `openssl ecparam -out ecparam.pem -name prime192v1`\n- `To create EC parameters with explicit parameters:`\n- `openssl ecparam -out ecparam.pem -name prime192v1 -paramenc explicit`\n- `To validate given EC parameters:`\n- `openssl ecparam -in ecparam.pem -check`\n- `To create EC parameters and a private key:`\n- `openssl ecparam -out eckey.pem -name prime192v1 -genkey`\n- `To change the point encoding to 'compressed':`\n- `openssl ecparam -in ecin.pem -out ecout.pem -convform compressed`\n- `To print out the EC parameters to standard output:`\n- `openssl ecparam -in ecparam.pem -noout -text`\n\n## See Also\n\n- openssl(1)\n- openssl-pkeyparam(1)\n- openssl-genpkey(1)\n- openssl-ec(1)\n- openssl-dsaparam(1)\n\n## Section Outline\n\n- **NAME** (2 lines)\n- **SYNOPSIS** (5 lines)\n- **DESCRIPTION** (5 lines)\n- **OPTIONS** (1 lines) — 20 subsections\n - -help (2 lines)\n - -inform (3 lines)\n - -outform (5 lines)\n - -in (3 lines)\n - -out (3 lines)\n - -noout (2 lines)\n - -text (2 lines)\n - -check (2 lines)\n - -check (3 lines)\n - -name (3 lines)\n - -list (2 lines)\n - -conv (6 lines)\n - -param (6 lines)\n - -no (3 lines)\n - -genkey (2 lines)\n - -engine (2 lines)\n - -rand -writerand (2 lines)\n - -provider (1 lines)\n - -provider-path (1 lines)\n - -propquery (5 lines)\n- **EXAMPLES** (27 lines)\n- **SEE ALSO** (2 lines)\n- **HISTORY** (4 lines)\n- **COPYRIGHT** (9 lines)\n\n## Full Content\n\n### NAME\n\nopenssl-ecparam - EC parameter manipulation and generation\n\n### SYNOPSIS\n\nopenssl ecparam [-help] [-inform DER|PEM] [-outform DER|PEM] [-in filename] [-out filename]\n[-noout] [-text] [-check] [-checknamed] [-name arg] [-listcurves] [-convform arg]\n[-paramenc arg] [-noseed] [-genkey] [-engine id] [-rand files] [-writerand file] [-provider\nname] [-provider-path path] [-propquery propq]\n\n### DESCRIPTION\n\nThis command is used to manipulate or generate EC parameter files.\n\nOpenSSL is currently not able to generate new groups and therefore this command can only\ncreate EC parameters from known (named) curves.\n\n### OPTIONS\n\n#### -help\n\nPrint out a usage message.\n\n#### -inform\n\nThe EC parameters input format; unspecified by default. See openssl-format-options(1)\nfor details.\n\n#### -outform\n\nThe EC parameters output format; the default is PEM. See openssl-format-options(1) for\ndetails.\n\nParameters are encoded as EcpkParameters as specified in IETF RFC 3279.\n\n#### -in\n\nThis specifies the input filename to read parameters from or standard input if this\noption is not specified.\n\n#### -out\n\nThis specifies the output filename parameters to. Standard output is used if this option\nis not present. The output filename should not be the same as the input filename.\n\n#### -noout\n\nThis option inhibits the output of the encoded version of the parameters.\n\n#### -text\n\nThis option prints out the EC parameters in human readable form.\n\n#### -check\n\nValidate the elliptic curve parameters.\n\n#### -check\n\nValidate the elliptic name curve parameters by checking if the curve parameters match any\nbuilt-in curves.\n\n#### -name\n\nUse the EC parameters with the specified 'short' name. Use -listcurves to get a list of\nall currently implemented EC parameters.\n\n#### -list\n\nPrint out a list of all currently implemented EC parameters names and exit.\n\n#### -conv\n\nThis specifies how the points on the elliptic curve are converted into octet strings.\nPossible values are: compressed, uncompressed (the default value) and hybrid. For more\ninformation regarding the point conversion forms please read the X9.62 standard. Note\nDue to patent issues the compressed option is disabled by default for binary curves and\ncan be enabled by defining the preprocessor macro OPENSSLECBINPTCOMP at compile time.\n\n#### -param\n\nThis specifies how the elliptic curve parameters are encoded. Possible value are:\nnamedcurve, i.e. the ec parameters are specified by an OID, or explicit where the ec\nparameters are explicitly given (see RFC 3279 for the definition of the EC parameters\nstructures). The default value is namedcurve. Note the implicitlyCA alternative, as\nspecified in RFC 3279, is currently not implemented in OpenSSL.\n\n#### -no\n\nThis option inhibits that the 'seed' for the parameter generation is included in the\nECParameters structure (see RFC 3279).\n\n#### -genkey\n\nThis option will generate an EC private key using the specified parameters.\n\n#### -engine\n\nSee \"Engine Options\" in openssl(1). This option is deprecated.\n\n#### -rand -writerand\n\nSee \"Random State Options\" in openssl(1) for details.\n\n#### -provider\n\n#### -provider-path\n\n#### -propquery\n\nSee \"Provider Options\" in openssl(1), provider(7), and property(7).\n\nThe openssl-genpkey(1) and openssl-pkeyparam(1) commands are capable of performing all the\noperations this command can, as well as supporting other public key types.\n\n### EXAMPLES\n\nThe documentation for the openssl-genpkey(1) and openssl-pkeyparam(1) commands contains\nexamples equivalent to the ones listed here.\n\nTo create EC parameters with the group 'prime192v1':\n\nopenssl ecparam -out ecparam.pem -name prime192v1\n\nTo create EC parameters with explicit parameters:\n\nopenssl ecparam -out ecparam.pem -name prime192v1 -paramenc explicit\n\nTo validate given EC parameters:\n\nopenssl ecparam -in ecparam.pem -check\n\nTo create EC parameters and a private key:\n\nopenssl ecparam -out eckey.pem -name prime192v1 -genkey\n\nTo change the point encoding to 'compressed':\n\nopenssl ecparam -in ecin.pem -out ecout.pem -convform compressed\n\nTo print out the EC parameters to standard output:\n\nopenssl ecparam -in ecparam.pem -noout -text\n\n### SEE ALSO\n\nopenssl(1), openssl-pkeyparam(1), openssl-genpkey(1), openssl-ec(1), openssl-dsaparam(1)\n\n### HISTORY\n\nThe -engine option was deprecated in OpenSSL 3.0.\n\nThe -C option was removed in OpenSSL 3.0.\n\n### COPYRIGHT\n\nCopyright 2003-2021 The OpenSSL Project Authors. All Rights Reserved.\n\nLicensed under the Apache License 2.0 (the \"License\"). You may not use this file except in\ncompliance with the License. You can obtain a copy in the file LICENSE in the source\ndistribution or at .\n\n\n\n3.0.2 2026-04-07 OPENSSL-ECPARAM(1SSL)\n\n" } ], "structuredContent": { "command": "OPENSSL-ECPARAM", "section": "1SSL", "mode": "man", "summary": "openssl-ecparam - EC parameter manipulation and generation", "synopsis": "openssl ecparam [-help] [-inform DER|PEM] [-outform DER|PEM] [-in filename] [-out filename]\n[-noout] [-text] [-check] [-checknamed] [-name arg] [-listcurves] [-convform arg]\n[-paramenc arg] [-noseed] [-genkey] [-engine id] [-rand files] [-writerand file] [-provider\nname] [-provider-path path] [-propquery propq]", "tldr_summary": null, "tldr_examples": [], "tldr_source": null, "flags": [ { "flag": "", "long": null, "arg": null, "description": "Print out a usage message." }, { "flag": "", "long": null, "arg": null, "description": "The EC parameters input format; unspecified by default. See openssl-format-options(1) for details." }, { "flag": "", "long": null, "arg": null, "description": "The EC parameters output format; the default is PEM. See openssl-format-options(1) for details. Parameters are encoded as EcpkParameters as specified in IETF RFC 3279." }, { "flag": "", "long": null, "arg": null, "description": "This specifies the input filename to read parameters from or standard input if this option is not specified." }, { "flag": "", "long": null, "arg": null, "description": "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." }, { "flag": "", "long": null, "arg": null, "description": "This option inhibits the output of the encoded version of the parameters." }, { "flag": "", "long": null, "arg": null, "description": "This option prints out the EC parameters in human readable form." }, { "flag": "", "long": null, "arg": null, "description": "Validate the elliptic curve parameters." }, { "flag": "", "long": null, "arg": null, "description": "Validate the elliptic name curve parameters by checking if the curve parameters match any built-in curves." }, { "flag": "", "long": null, "arg": null, "description": "Use the EC parameters with the specified 'short' name. Use -listcurves to get a list of all currently implemented EC parameters." }, { "flag": "", "long": null, "arg": null, "description": "Print out a list of all currently implemented EC parameters names and exit." }, { "flag": "", "long": null, "arg": null, "description": "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 OPENSSLECBINPTCOMP at compile time." }, { "flag": "", "long": null, "arg": null, "description": "This specifies how the elliptic curve parameters are encoded. Possible value are: namedcurve, i.e. the ec parameters are specified by an 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." }, { "flag": "", "long": null, "arg": null, "description": "This option inhibits that the 'seed' for the parameter generation is included in the ECParameters structure (see RFC 3279)." }, { "flag": "", "long": null, "arg": null, "description": "This option will generate an EC private key using the specified parameters." }, { "flag": "", "long": null, "arg": null, "description": "See \"Engine Options\" in openssl(1). This option is deprecated." }, { "flag": "", "long": null, "arg": null, "description": "See \"Random State Options\" in openssl(1) for details." }, { "flag": "", "long": null, "arg": null, "description": "" }, { "flag": "", "long": null, "arg": null, "description": "" }, { "flag": "", "long": null, "arg": null, "description": "See \"Provider Options\" in openssl(1), provider(7), and property(7). The openssl-genpkey(1) and openssl-pkeyparam(1) commands are capable of performing all the operations this command can, as well as supporting other public key types." } ], "examples": [ "The documentation for the openssl-genpkey(1) and openssl-pkeyparam(1) commands contains", "examples equivalent to the ones listed here.", "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": [ { "name": "openssl", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/openssl/1/json" }, { "name": "openssl-pkeyparam", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/openssl-pkeyparam/1/json" }, { "name": "openssl-genpkey", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/openssl-genpkey/1/json" }, { "name": "openssl-ec", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/openssl-ec/1/json" }, { "name": "openssl-dsaparam", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/openssl-dsaparam/1/json" } ], "section_outline": [ { "name": "NAME", "lines": 2, "subsections": [] }, { "name": "SYNOPSIS", "lines": 5, "subsections": [] }, { "name": "DESCRIPTION", "lines": 5, "subsections": [] }, { "name": "OPTIONS", "lines": 1, "subsections": [ { "name": "-help", "lines": 2 }, { "name": "-inform", "lines": 3 }, { "name": "-outform", "lines": 5 }, { "name": "-in", "lines": 3 }, { "name": "-out", "lines": 3 }, { "name": "-noout", "lines": 2 }, { "name": "-text", "lines": 2 }, { "name": "-check", "lines": 2 }, { "name": "-check", "lines": 3 }, { "name": "-name", "lines": 3 }, { "name": "-list", "lines": 2 }, { "name": "-conv", "lines": 6 }, { "name": "-param", "lines": 6 }, { "name": "-no", "lines": 3 }, { "name": "-genkey", "lines": 2 }, { "name": "-engine", "lines": 2 }, { "name": "-rand -writerand", "lines": 2 }, { "name": "-provider", "lines": 1 }, { "name": "-provider-path", "lines": 1 }, { "name": "-propquery", "lines": 5 } ] }, { "name": "EXAMPLES", "lines": 27, "subsections": [] }, { "name": "SEE ALSO", "lines": 2, "subsections": [] }, { "name": "HISTORY", "lines": 4, "subsections": [] }, { "name": "COPYRIGHT", "lines": 9, "subsections": [] } ], "sections": { "NAME": { "content": "openssl-ecparam - EC parameter manipulation and generation\n", "subsections": [] }, "SYNOPSIS": { "content": "openssl ecparam [-help] [-inform DER|PEM] [-outform DER|PEM] [-in filename] [-out filename]\n[-noout] [-text] [-check] [-checknamed] [-name arg] [-listcurves] [-convform arg]\n[-paramenc arg] [-noseed] [-genkey] [-engine id] [-rand files] [-writerand file] [-provider\nname] [-provider-path path] [-propquery propq]\n", "subsections": [] }, "DESCRIPTION": { "content": "This command is used to manipulate or generate EC parameter files.\n\nOpenSSL is currently not able to generate new groups and therefore this command can only\ncreate EC parameters from known (named) curves.\n", "subsections": [] }, "OPTIONS": { "content": "", "subsections": [ { "name": "-help", "content": "Print out a usage message.\n" }, { "name": "-inform", "content": "The EC parameters input format; unspecified by default. See openssl-format-options(1)\nfor details.\n" }, { "name": "-outform", "content": "The EC parameters output format; the default is PEM. See openssl-format-options(1) for\ndetails.\n\nParameters are encoded as EcpkParameters as specified in IETF RFC 3279.\n" }, { "name": "-in", "content": "This specifies the input filename to read parameters from or standard input if this\noption is not specified.\n" }, { "name": "-out", "content": "This specifies the output filename parameters to. Standard output is used if this option\nis not present. The output filename should not be the same as the input filename.\n" }, { "name": "-noout", "content": "This option inhibits the output of the encoded version of the parameters.\n" }, { "name": "-text", "content": "This option prints out the EC parameters in human readable form.\n" }, { "name": "-check", "content": "Validate the elliptic curve parameters.\n" }, { "name": "-check", "content": "Validate the elliptic name curve parameters by checking if the curve parameters match any\nbuilt-in curves.\n" }, { "name": "-name", "content": "Use the EC parameters with the specified 'short' name. Use -listcurves to get a list of\nall currently implemented EC parameters.\n" }, { "name": "-list", "content": "Print out a list of all currently implemented EC parameters names and exit.\n" }, { "name": "-conv", "content": "This specifies how the points on the elliptic curve are converted into octet strings.\nPossible values are: compressed, uncompressed (the default value) and hybrid. For more\ninformation regarding the point conversion forms please read the X9.62 standard. Note\nDue to patent issues the compressed option is disabled by default for binary curves and\ncan be enabled by defining the preprocessor macro OPENSSLECBINPTCOMP at compile time.\n" }, { "name": "-param", "content": "This specifies how the elliptic curve parameters are encoded. Possible value are:\nnamedcurve, i.e. the ec parameters are specified by an OID, or explicit where the ec\nparameters are explicitly given (see RFC 3279 for the definition of the EC parameters\nstructures). The default value is namedcurve. Note the implicitlyCA alternative, as\nspecified in RFC 3279, is currently not implemented in OpenSSL.\n" }, { "name": "-no", "content": "This option inhibits that the 'seed' for the parameter generation is included in the\nECParameters structure (see RFC 3279).\n" }, { "name": "-genkey", "content": "This option will generate an EC private key using the specified parameters.\n" }, { "name": "-engine", "content": "See \"Engine Options\" in openssl(1). This option is deprecated.\n" }, { "name": "-rand -writerand", "content": "See \"Random State Options\" in openssl(1) for details.\n" }, { "name": "-provider", "content": "" }, { "name": "-provider-path", "content": "" }, { "name": "-propquery", "content": "See \"Provider Options\" in openssl(1), provider(7), and property(7).\n\nThe openssl-genpkey(1) and openssl-pkeyparam(1) commands are capable of performing all the\noperations this command can, as well as supporting other public key types.\n" } ] }, "EXAMPLES": { "content": "The documentation for the openssl-genpkey(1) and openssl-pkeyparam(1) commands contains\nexamples equivalent to the ones listed here.\n\nTo create EC parameters with the group 'prime192v1':\n\nopenssl ecparam -out ecparam.pem -name prime192v1\n\nTo create EC parameters with explicit parameters:\n\nopenssl ecparam -out ecparam.pem -name prime192v1 -paramenc explicit\n\nTo validate given EC parameters:\n\nopenssl ecparam -in ecparam.pem -check\n\nTo create EC parameters and a private key:\n\nopenssl ecparam -out eckey.pem -name prime192v1 -genkey\n\nTo change the point encoding to 'compressed':\n\nopenssl ecparam -in ecin.pem -out ecout.pem -convform compressed\n\nTo print out the EC parameters to standard output:\n\nopenssl ecparam -in ecparam.pem -noout -text\n", "subsections": [] }, "SEE ALSO": { "content": "openssl(1), openssl-pkeyparam(1), openssl-genpkey(1), openssl-ec(1), openssl-dsaparam(1)\n", "subsections": [] }, "HISTORY": { "content": "The -engine option was deprecated in OpenSSL 3.0.\n\nThe -C option was removed in OpenSSL 3.0.\n", "subsections": [] }, "COPYRIGHT": { "content": "Copyright 2003-2021 The OpenSSL Project Authors. All Rights Reserved.\n\nLicensed under the Apache License 2.0 (the \"License\"). You may not use this file except in\ncompliance with the License. You can obtain a copy in the file LICENSE in the source\ndistribution or at .\n\n\n\n3.0.2 2026-04-07 OPENSSL-ECPARAM(1SSL)", "subsections": [] } } } }