1RSA(1) OpenSSL RSA(1)
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6 rsa - RSA key processing tool
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9 openssl rsa [-inform PEM|NET|DER] [-outform PEM|NET|DER] [-in filename]
10 [-passin arg] [-out filename] [-passout arg] [-sgckey] [-aes128]
11 [-aes192] [-aes256] [-camellia128] [-camellia192] [-camellia256] [-des]
12 [-des3] [-idea] [-text] [-noout] [-modulus] [-check] [-pubin] [-pubout]
13 [-RSAPublicKey_in] [-RSAPublicKey_out] [-engine id]
14
16 The rsa command processes RSA keys. They can be converted between
17 various forms and their components printed out. Note this command uses
18 the traditional SSLeay compatible format for private key encryption:
19 newer applications should use the more secure PKCS#8 format using the
20 pkcs8 utility.
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23 -inform DER|NET|PEM
24 This specifies the input format. The DER option uses an ASN1 DER
25 encoded form compatible with the PKCS#1 RSAPrivateKey or
26 SubjectPublicKeyInfo format. The PEM form is the default format:
27 it consists of the DER format base64 encoded with additional header
28 and footer lines. On input PKCS#8 format private keys are also
29 accepted. The NET form is a format is described in the NOTES
30 section.
31 -outform DER|NET|PEM
33 This specifies the output format, the options have the same meaning
34 as the -inform option.
35 -in filename
37 This specifies the input filename to read a key from or standard
38 input if this option is not specified. If the key is encrypted a
39 pass phrase will be prompted for.
40 -passin arg
42 the input file password source. For more information about the
43 format of arg see the PASS PHRASE ARGUMENTS section in openssl(1).
44 -out filename
46 This specifies the output filename to write a key to or standard
47 output if this option is not specified. If any encryption options
48 are set then a pass phrase will be prompted for. The output
49 filename should not be the same as the input filename.
50 -passout password
52 the output file password source. For more information about the
53 format of arg see the PASS PHRASE ARGUMENTS section in openssl(1).
54 -sgckey
56 use the modified NET algorithm used with some versions of Microsoft
57 IIS and SGC keys.
58 -aes128|-aes192|-aes256|-camellia128|-camellia192|-camellia256|-des|-des3|-idea
60 These options encrypt the private key with the specified cipher
61 before outputting it. A pass phrase is prompted for. If none of
62 these options is specified the key is written in plain text. This
63 means that using the rsa utility to read in an encrypted key with
64 no encryption option can be used to remove the pass phrase from a
65 key, or by setting the encryption options it can be use to add or
66 change the pass phrase. These options can only be used with PEM
67 format output files.
68 -text
70 prints out the various public or private key components in plain
71 text in addition to the encoded version.
72 -noout
74 this option prevents output of the encoded version of the key.
75 -modulus
77 this option prints out the value of the modulus of the key.
78 -check
80 this option checks the consistency of an RSA private key.
81 -pubin
83 by default a private key is read from the input file: with this
84 option a public key is read instead.
85 -pubout
87 by default a private key is output: with this option a public key
88 will be output instead. This option is automatically set if the
89 input is a public key.
90 -RSAPublicKey_in, -RSAPublicKey_out
92 like -pubin and -pubout except RSAPublicKey format is used instead.
93 -engine id
95 specifying an engine (by its unique id string) will cause rsa to
96 attempt to obtain a functional reference to the specified engine,
97 thus initialising it if needed. The engine will then be set as the
98 default for all available algorithms.
99
101 The PEM private key format uses the header and footer lines:
102 -----BEGIN RSA PRIVATE KEY-----
104 -----END RSA PRIVATE KEY-----
105 The PEM public key format uses the header and footer lines:
107 -----BEGIN PUBLIC KEY-----
109 -----END PUBLIC KEY-----
110 The PEM RSAPublicKey format uses the header and footer lines:
112 -----BEGIN RSA PUBLIC KEY-----
114 -----END RSA PUBLIC KEY-----
115 The NET form is a format compatible with older Netscape servers and
117 Microsoft IIS .key files, this uses unsalted RC4 for its encryption.
118 It is not very secure and so should only be used when necessary.
119 Some newer version of IIS have additional data in the exported .key
121 files. To use these with the utility, view the file with a binary
122 editor and look for the string "private-key", then trace back to the
123 byte sequence 0x30, 0x82 (this is an ASN1 SEQUENCE). Copy all the data
124 from this point onwards to another file and use that as the input to
125 the rsa utility with the -inform NET option. If you get an error after
126 entering the password try the -sgckey option.
127
129 To remove the pass phrase on an RSA private key:
130 openssl rsa -in key.pem -out keyout.pem
132 To encrypt a private key using triple DES:
134 openssl rsa -in key.pem -des3 -out keyout.pem
136 To convert a private key from PEM to DER format:
138 openssl rsa -in key.pem -outform DER -out keyout.der
140 To print out the components of a private key to standard output:
142 openssl rsa -in key.pem -text -noout
144 To just output the public part of a private key:
146 openssl rsa -in key.pem -pubout -out pubkey.pem
148 Output the public part of a private key in RSAPublicKey format:
150 openssl rsa -in key.pem -RSAPublicKey_out -out pubkey.pem
152
154 The command line password arguments don't currently work with NET
155 format.
156 There should be an option that automatically handles .key files,
158 without having to manually edit them.
159
161 pkcs8(1), dsa(1), genrsa(1), gendsa(1)
1621.0.2k 2017-01-26 RSA(1)