1ECPARAM(1) OpenSSL ECPARAM(1)
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6 ecparam - EC parameter manipulation and generation
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9 openssl ecparam [-inform DER|PEM] [-outform DER|PEM] [-in filename]
10 [-out filename] [-noout] [-text] [-C] [-check] [-name arg]
11 [-list_curves] [-conv_form arg] [-param_enc arg] [-no_seed] [-rand
12 file(s)] [-genkey] [-engine id]
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15 This command is used to manipulate or generate EC parameter files.
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18 -inform DER|PEM
19 This specifies the input format. The DER option uses an ASN.1 DER
20 encoded form compatible with RFC 3279 EcpkParameters. The PEM form
21 is the default format: it consists of the DER format base64 encoded
22 with additional header and footer lines.
23 -outform DER|PEM
25 This specifies the output format, the options have the same meaning
26 as the -inform option.
27 -in filename
29 This specifies the input filename to read parameters from or
30 standard input if this option is not specified.
31 -out filename
33 This specifies the output filename parameters to. Standard output
34 is used if this option is not present. The output filename should
35 not be the same as the input filename.
36 -noout
38 This option inhibits the output of the encoded version of the
39 parameters.
40 -text
42 This option prints out the EC parameters in human readable form.
43 -C This option converts the EC parameters into C code. The parameters
45 can then be loaded by calling the get_ec_group_XXX() function.
46 -check
48 Validate the elliptic curve parameters.
49 -name arg
51 Use the EC parameters with the specified 'short' name. Use
52 -list_curves to get a list of all currently implemented EC
53 parameters.
54 -list_curves
56 If this options is specified ecparam will print out a list of all
57 currently implemented EC parameters names and exit.
58 -conv_form
60 This specifies how the points on the elliptic curve are converted
61 into octet strings. Possible values are: compressed (the default
62 value), uncompressed and hybrid. For more information regarding the
63 point conversion forms please read the X9.62 standard. Note Due to
64 patent issues the compressed option is disabled by default for
65 binary curves and can be enabled by defining the preprocessor macro
66 OPENSSL_EC_BIN_PT_COMP at compile time.
67 -param_enc arg
69 This specifies how the elliptic curve parameters are encoded.
70 Possible value are: named_curve, i.e. the ec parameters are
71 specified by a OID, or explicit where the ec parameters are
72 explicitly given (see RFC 3279 for the definition of the EC
73 parameters structures). The default value is named_curve. Note the
74 implicitlyCA alternative ,as specified in RFC 3279, is currently
75 not implemented in OpenSSL.
76 -no_seed
78 This option inhibits that the 'seed' for the parameter generation
79 is included in the ECParameters structure (see RFC 3279).
80 -genkey
82 This option will generate a EC private key using the specified
83 parameters.
84 -rand file(s)
86 a file or files containing random data used to seed the random
87 number generator, or an EGD socket (see RAND_egd(3)). Multiple
88 files can be specified separated by a OS-dependent character. The
89 separator is ; for MS-Windows, , for OpenVMS, and : for all others.
90 -engine id
92 specifying an engine (by its unique id string) will cause ecparam
93 to attempt to obtain a functional reference to the specified
94 engine, thus initialising it if needed. The engine will then be set
95 as the default for all available algorithms.
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98 PEM format EC parameters use the header and footer lines:
99 -----BEGIN EC PARAMETERS-----
101 -----END EC PARAMETERS-----
102 OpenSSL is currently not able to generate new groups and therefore
104 ecparam can only create EC parameters from known (named) curves.
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107 To create EC parameters with the group 'prime192v1':
108 openssl ecparam -out ec_param.pem -name prime192v1
110 To create EC parameters with explicit parameters:
112 openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicit
114 To validate given EC parameters:
116 openssl ecparam -in ec_param.pem -check
118 To create EC parameters and a private key:
120 openssl ecparam -out ec_key.pem -name prime192v1 -genkey
122 To change the point encoding to 'compressed':
124 openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressed
126 To print out the EC parameters to standard output:
128 openssl ecparam -in ec_param.pem -noout -text
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132 ec(1), dsaparam(1)
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135 The ecparam command was first introduced in OpenSSL 0.9.8.
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138 Nils Larsch for the OpenSSL project (http://www.openssl.org)
1391.0.2k 2017-01-26 ECPARAM(1)