1PKCS8(1)                            OpenSSL                           PKCS8(1)
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NAME

6       pkcs8 - PKCS#8 format private key conversion tool
7

SYNOPSIS

9       openssl pkcs8 [-topk8] [-inform PEM|DER] [-outform PEM|DER] [-in
10       filename] [-passin arg] [-out filename] [-passout arg] [-noiter]
11       [-nocrypt] [-nooct] [-embed] [-nsdb] [-v2 alg] [-v1 alg] [-engine id]
12

DESCRIPTION

14       The pkcs8 command processes private keys in PKCS#8 format. It can
15       handle both unencrypted PKCS#8 PrivateKeyInfo format and
16       EncryptedPrivateKeyInfo format with a variety of PKCS#5 (v1.5 and v2.0)
17       and PKCS#12 algorithms.
18

COMMAND OPTIONS

20       -topk8
21           Normally a PKCS#8 private key is expected on input and a
22           traditional format private key will be written. With the -topk8
23           option the situation is reversed: it reads a traditional format
24           private key and writes a PKCS#8 format key.
25
26       -inform DER|PEM
27           This specifies the input format. If a PKCS#8 format key is expected
28           on input then either a DER or PEM encoded version of a PKCS#8 key
29           will be expected. Otherwise the DER or PEM format of the
30           traditional format private key is used.
31
32       -outform DER|PEM
33           This specifies the output format, the options have the same meaning
34           as the -inform option.
35
36       -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
41       -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
45       -out filename
46           This specifies the output filename to write a key to or standard
47           output by default. If any encryption options are set then a pass
48           phrase will be prompted for. The output filename should not be the
49           same as the input filename.
50
51       -passout arg
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
55       -nocrypt
56           PKCS#8 keys generated or input are normally PKCS#8
57           EncryptedPrivateKeyInfo structures using an appropriate password
58           based encryption algorithm. With this option an unencrypted
59           PrivateKeyInfo structure is expected or output.  This option does
60           not encrypt private keys at all and should only be used when
61           absolutely necessary. Certain software such as some versions of
62           Java code signing software used unencrypted private keys.
63
64       -nooct
65           This option generates RSA private keys in a broken format that some
66           software uses. Specifically the private key should be enclosed in a
67           OCTET STRING but some software just includes the structure itself
68           without the surrounding OCTET STRING.
69
70       -embed
71           This option generates DSA keys in a broken format. The DSA
72           parameters are embedded inside the PrivateKey structure. In this
73           form the OCTET STRING contains an ASN1 SEQUENCE consisting of two
74           structures: a SEQUENCE containing the parameters and an ASN1
75           INTEGER containing the private key.
76
77       -nsdb
78           This option generates DSA keys in a broken format compatible with
79           Netscape private key databases. The PrivateKey contains a SEQUENCE
80           consisting of the public and private keys respectively.
81
82       -v2 alg
83           This option enables the use of PKCS#5 v2.0 algorithms. Normally
84           PKCS#8 private keys are encrypted with the password based
85           encryption algorithm called pbeWithMD5AndDES-CBC this uses 56 bit
86           DES encryption but it was the strongest encryption algorithm
87           supported in PKCS#5 v1.5. Using the -v2 option PKCS#5 v2.0
88           algorithms are used which can use any encryption algorithm such as
89           168 bit triple DES or 128 bit RC2 however not many implementations
90           support PKCS#5 v2.0 yet. If you are just using private keys with
91           OpenSSL then this doesn't matter.
92
93           The alg argument is the encryption algorithm to use, valid values
94           include des, des3 and rc2. It is recommended that des3 is used.
95
96       -v1 alg
97           This option specifies a PKCS#5 v1.5 or PKCS#12 algorithm to use. A
98           complete list of possible algorithms is included below.
99
100       -engine id
101           specifying an engine (by its unique id string) will cause pkcs8 to
102           attempt to obtain a functional reference to the specified engine,
103           thus initialising it if needed. The engine will then be set as the
104           default for all available algorithms.
105

NOTES

107       The encrypted form of a PEM encode PKCS#8 files uses the following
108       headers and footers:
109
110        -----BEGIN ENCRYPTED PRIVATE KEY-----
111        -----END ENCRYPTED PRIVATE KEY-----
112
113       The unencrypted form uses:
114
115        -----BEGIN PRIVATE KEY-----
116        -----END PRIVATE KEY-----
117
118       Private keys encrypted using PKCS#5 v2.0 algorithms and high iteration
119       counts are more secure that those encrypted using the traditional
120       SSLeay compatible formats. So if additional security is considered
121       important the keys should be converted.
122
123       The default encryption is only 56 bits because this is the encryption
124       that most current implementations of PKCS#8 will support.
125
126       Some software may use PKCS#12 password based encryption algorithms with
127       PKCS#8 format private keys: these are handled automatically but there
128       is no option to produce them.
129
130       It is possible to write out DER encoded encrypted private keys in
131       PKCS#8 format because the encryption details are included at an ASN1
132       level whereas the traditional format includes them at a PEM level.
133

PKCS#5 v1.5 and PKCS#12 algorithms.

135       Various algorithms can be used with the -v1 command line option,
136       including PKCS#5 v1.5 and PKCS#12. These are described in more detail
137       below.
138
139       PBE-MD2-DES PBE-MD5-DES
140           These algorithms were included in the original PKCS#5 v1.5
141           specification.  They only offer 56 bits of protection since they
142           both use DES.
143
144       PBE-SHA1-RC2-64 PBE-MD2-RC2-64 PBE-MD5-RC2-64 PBE-SHA1-DES
145           These algorithms are not mentioned in the original PKCS#5 v1.5
146           specification but they use the same key derivation algorithm and
147           are supported by some software. They are mentioned in PKCS#5 v2.0.
148           They use either 64 bit RC2 or 56 bit DES.
149
150       PBE-SHA1-RC4-128 PBE-SHA1-RC4-40 PBE-SHA1-3DES PBE-SHA1-2DES
151       PBE-SHA1-RC2-128 PBE-SHA1-RC2-40
152           These algorithms use the PKCS#12 password based encryption
153           algorithm and allow strong encryption algorithms like triple DES or
154           128 bit RC2 to be used.
155

EXAMPLES

157       Convert a private from traditional to PKCS#5 v2.0 format using triple
158       DES:
159
160        openssl pkcs8 -in key.pem -topk8 -v2 des3 -out enckey.pem
161
162       Convert a private key to PKCS#8 using a PKCS#5 1.5 compatible algorithm
163       (DES):
164
165        openssl pkcs8 -in key.pem -topk8 -out enckey.pem
166
167       Convert a private key to PKCS#8 using a PKCS#12 compatible algorithm
168       (3DES):
169
170        openssl pkcs8 -in key.pem -topk8 -out enckey.pem -v1 PBE-SHA1-3DES
171
172       Read a DER unencrypted PKCS#8 format private key:
173
174        openssl pkcs8 -inform DER -nocrypt -in key.der -out key.pem
175
176       Convert a private key from any PKCS#8 format to traditional format:
177
178        openssl pkcs8 -in pk8.pem -out key.pem
179

STANDARDS

181       Test vectors from this PKCS#5 v2.0 implementation were posted to the
182       pkcs-tng mailing list using triple DES, DES and RC2 with high iteration
183       counts, several people confirmed that they could decrypt the private
184       keys produced and Therefore it can be assumed that the PKCS#5 v2.0
185       implementation is reasonably accurate at least as far as these
186       algorithms are concerned.
187
188       The format of PKCS#8 DSA (and other) private keys is not well
189       documented: it is hidden away in PKCS#11 v2.01, section 11.9. OpenSSL's
190       default DSA PKCS#8 private key format complies with this standard.
191

BUGS

193       There should be an option that prints out the encryption algorithm in
194       use and other details such as the iteration count.
195
196       PKCS#8 using triple DES and PKCS#5 v2.0 should be the default private
197       key format for OpenSSL: for compatibility several of the utilities use
198       the old format at present.
199

SEE ALSO

201       dsa(1), rsa(1), genrsa(1), gendsa(1)
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2051.0.0e                            2009-04-10                          PKCS8(1)
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