pkcs8.pod 9.8 KB

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  1. =pod
  2. =head1 NAME
  3. openssl-pkcs8,
  4. pkcs8 - PKCS#8 format private key conversion tool
  5. =head1 SYNOPSIS
  6. B<openssl> B<pkcs8>
  7. [B<-help>]
  8. [B<-topk8>]
  9. [B<-inform PEM|DER>]
  10. [B<-outform PEM|DER>]
  11. [B<-in filename>]
  12. [B<-passin arg>]
  13. [B<-out filename>]
  14. [B<-passout arg>]
  15. [B<-iter count>]
  16. [B<-noiter>]
  17. [B<-rand file...>]
  18. [B<-writerand file>]
  19. [B<-nocrypt>]
  20. [B<-traditional>]
  21. [B<-v2 alg>]
  22. [B<-v2prf alg>]
  23. [B<-v1 alg>]
  24. [B<-engine id>]
  25. [B<-scrypt>]
  26. [B<-scrypt_N N>]
  27. [B<-scrypt_r r>]
  28. [B<-scrypt_p p>]
  29. =head1 DESCRIPTION
  30. The B<pkcs8> command processes private keys in PKCS#8 format. It can handle
  31. both unencrypted PKCS#8 PrivateKeyInfo format and EncryptedPrivateKeyInfo
  32. format with a variety of PKCS#5 (v1.5 and v2.0) and PKCS#12 algorithms.
  33. =head1 OPTIONS
  34. =over 4
  35. =item B<-help>
  36. Print out a usage message.
  37. =item B<-topk8>
  38. Normally a PKCS#8 private key is expected on input and a private key will be
  39. written to the output file. With the B<-topk8> option the situation is
  40. reversed: it reads a private key and writes a PKCS#8 format key.
  41. =item B<-inform DER|PEM>
  42. This specifies the input format: see L<KEY FORMATS> for more details. The default
  43. format is PEM.
  44. =item B<-outform DER|PEM>
  45. This specifies the output format: see L<KEY FORMATS> for more details. The default
  46. format is PEM.
  47. =item B<-traditional>
  48. When this option is present and B<-topk8> is not a traditional format private
  49. key is written.
  50. =item B<-in filename>
  51. This specifies the input filename to read a key from or standard input if this
  52. option is not specified. If the key is encrypted a pass phrase will be
  53. prompted for.
  54. =item B<-passin arg>
  55. The input file password source. For more information about the format of B<arg>
  56. see L<openssl(1)/Pass Phrase Options>.
  57. =item B<-out filename>
  58. This specifies the output filename to write a key to or standard output by
  59. default. If any encryption options are set then a pass phrase will be
  60. prompted for. The output filename should B<not> be the same as the input
  61. filename.
  62. =item B<-passout arg>
  63. The output file password source. For more information about the format of B<arg>
  64. see L<openssl(1)/Pass Phrase Options>.
  65. =item B<-iter count>
  66. When creating new PKCS#8 containers, use a given number of iterations on
  67. the password in deriving the encryption key for the PKCS#8 output.
  68. High values increase the time required to brute-force a PKCS#8 container.
  69. =item B<-nocrypt>
  70. PKCS#8 keys generated or input are normally PKCS#8 EncryptedPrivateKeyInfo
  71. structures using an appropriate password based encryption algorithm. With
  72. this option an unencrypted PrivateKeyInfo structure is expected or output.
  73. This option does not encrypt private keys at all and should only be used
  74. when absolutely necessary. Certain software such as some versions of Java
  75. code signing software used unencrypted private keys.
  76. =item B<-rand file...>
  77. A file or files containing random data used to seed the random number
  78. generator.
  79. Multiple files can be specified separated by an OS-dependent character.
  80. The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
  81. all others.
  82. =item [B<-writerand file>]
  83. Writes random data to the specified I<file> upon exit.
  84. This can be used with a subsequent B<-rand> flag.
  85. =item B<-v2 alg>
  86. This option sets the PKCS#5 v2.0 algorithm.
  87. The B<alg> argument is the encryption algorithm to use, valid values include
  88. B<aes128>, B<aes256> and B<des3>. If this option isn't specified then B<aes256>
  89. is used.
  90. =item B<-v2prf alg>
  91. This option sets the PRF algorithm to use with PKCS#5 v2.0. A typical value
  92. value would be B<hmacWithSHA256>. If this option isn't set then the default
  93. for the cipher is used or B<hmacWithSHA256> if there is no default.
  94. Some implementations may not support custom PRF algorithms and may require
  95. the B<hmacWithSHA1> option to work.
  96. =item B<-v1 alg>
  97. This option indicates a PKCS#5 v1.5 or PKCS#12 algorithm should be used. Some
  98. older implementations may not support PKCS#5 v2.0 and may require this option.
  99. If not specified PKCS#5 v2.0 form is used.
  100. =item B<-engine id>
  101. Specifying an engine (by its unique B<id> string) will cause B<pkcs8>
  102. to attempt to obtain a functional reference to the specified engine,
  103. thus initialising it if needed. The engine will then be set as the default
  104. for all available algorithms.
  105. =item B<-scrypt>
  106. Uses the B<scrypt> algorithm for private key encryption using default
  107. parameters: currently N=16384, r=8 and p=1 and AES in CBC mode with a 256 bit
  108. key. These parameters can be modified using the B<-scrypt_N>, B<-scrypt_r>,
  109. B<-scrypt_p> and B<-v2> options.
  110. =item B<-scrypt_N N> B<-scrypt_r r> B<-scrypt_p p>
  111. Sets the scrypt B<N>, B<r> or B<p> parameters.
  112. =back
  113. =head1 KEY FORMATS
  114. Various different formats are used by the pkcs8 utility. These are detailed
  115. below.
  116. If a key is being converted from PKCS#8 form (i.e. the B<-topk8> option is
  117. not used) then the input file must be in PKCS#8 format. An encrypted
  118. key is expected unless B<-nocrypt> is included.
  119. If B<-topk8> is not used and B<PEM> mode is set the output file will be an
  120. unencrypted private key in PKCS#8 format. If the B<-traditional> option is
  121. used then a traditional format private key is written instead.
  122. If B<-topk8> is not used and B<DER> mode is set the output file will be an
  123. unencrypted private key in traditional DER format.
  124. If B<-topk8> is used then any supported private key can be used for the input
  125. file in a format specified by B<-inform>. The output file will be encrypted
  126. PKCS#8 format using the specified encryption parameters unless B<-nocrypt>
  127. is included.
  128. =head1 NOTES
  129. By default, when converting a key to PKCS#8 format, PKCS#5 v2.0 using 256 bit
  130. AES with HMAC and SHA256 is used.
  131. Some older implementations do not support PKCS#5 v2.0 format and require
  132. the older PKCS#5 v1.5 form instead, possibly also requiring insecure weak
  133. encryption algorithms such as 56 bit DES.
  134. The encrypted form of a PEM encode PKCS#8 files uses the following
  135. headers and footers:
  136. -----BEGIN ENCRYPTED PRIVATE KEY-----
  137. -----END ENCRYPTED PRIVATE KEY-----
  138. The unencrypted form uses:
  139. -----BEGIN PRIVATE KEY-----
  140. -----END PRIVATE KEY-----
  141. Private keys encrypted using PKCS#5 v2.0 algorithms and high iteration
  142. counts are more secure that those encrypted using the traditional
  143. SSLeay compatible formats. So if additional security is considered
  144. important the keys should be converted.
  145. It is possible to write out DER encoded encrypted private keys in
  146. PKCS#8 format because the encryption details are included at an ASN1
  147. level whereas the traditional format includes them at a PEM level.
  148. =head1 PKCS#5 v1.5 and PKCS#12 algorithms.
  149. Various algorithms can be used with the B<-v1> command line option,
  150. including PKCS#5 v1.5 and PKCS#12. These are described in more detail
  151. below.
  152. =over 4
  153. =item B<PBE-MD2-DES PBE-MD5-DES>
  154. These algorithms were included in the original PKCS#5 v1.5 specification.
  155. They only offer 56 bits of protection since they both use DES.
  156. =item B<PBE-SHA1-RC2-64>, B<PBE-MD2-RC2-64>, B<PBE-MD5-RC2-64>, B<PBE-SHA1-DES>
  157. These algorithms are not mentioned in the original PKCS#5 v1.5 specification
  158. but they use the same key derivation algorithm and are supported by some
  159. software. They are mentioned in PKCS#5 v2.0. They use either 64 bit RC2 or
  160. 56 bit DES.
  161. =item B<PBE-SHA1-RC4-128>, B<PBE-SHA1-RC4-40>, B<PBE-SHA1-3DES>, B<PBE-SHA1-2DES>, B<PBE-SHA1-RC2-128>, B<PBE-SHA1-RC2-40>
  162. These algorithms use the PKCS#12 password based encryption algorithm and
  163. allow strong encryption algorithms like triple DES or 128 bit RC2 to be used.
  164. =back
  165. =head1 EXAMPLES
  166. Convert a private key to PKCS#8 format using default parameters (AES with
  167. 256 bit key and B<hmacWithSHA256>):
  168. openssl pkcs8 -in key.pem -topk8 -out enckey.pem
  169. Convert a private key to PKCS#8 unencrypted format:
  170. openssl pkcs8 -in key.pem -topk8 -nocrypt -out enckey.pem
  171. Convert a private key to PKCS#5 v2.0 format using triple DES:
  172. openssl pkcs8 -in key.pem -topk8 -v2 des3 -out enckey.pem
  173. Convert a private key to PKCS#5 v2.0 format using AES with 256 bits in CBC
  174. mode and B<hmacWithSHA512> PRF:
  175. openssl pkcs8 -in key.pem -topk8 -v2 aes-256-cbc -v2prf hmacWithSHA512 -out enckey.pem
  176. Convert a private key to PKCS#8 using a PKCS#5 1.5 compatible algorithm
  177. (DES):
  178. openssl pkcs8 -in key.pem -topk8 -v1 PBE-MD5-DES -out enckey.pem
  179. Convert a private key to PKCS#8 using a PKCS#12 compatible algorithm
  180. (3DES):
  181. openssl pkcs8 -in key.pem -topk8 -out enckey.pem -v1 PBE-SHA1-3DES
  182. Read a DER unencrypted PKCS#8 format private key:
  183. openssl pkcs8 -inform DER -nocrypt -in key.der -out key.pem
  184. Convert a private key from any PKCS#8 encrypted format to traditional format:
  185. openssl pkcs8 -in pk8.pem -traditional -out key.pem
  186. Convert a private key to PKCS#8 format, encrypting with AES-256 and with
  187. one million iterations of the password:
  188. openssl pkcs8 -in key.pem -topk8 -v2 aes-256-cbc -iter 1000000 -out pk8.pem
  189. =head1 STANDARDS
  190. Test vectors from this PKCS#5 v2.0 implementation were posted to the
  191. pkcs-tng mailing list using triple DES, DES and RC2 with high iteration
  192. counts, several people confirmed that they could decrypt the private
  193. keys produced and therefore, it can be assumed that the PKCS#5 v2.0
  194. implementation is reasonably accurate at least as far as these
  195. algorithms are concerned.
  196. The format of PKCS#8 DSA (and other) private keys is not well documented:
  197. it is hidden away in PKCS#11 v2.01, section 11.9. OpenSSL's default DSA
  198. PKCS#8 private key format complies with this standard.
  199. =head1 BUGS
  200. There should be an option that prints out the encryption algorithm
  201. in use and other details such as the iteration count.
  202. =head1 SEE ALSO
  203. L<dsa(1)>, L<rsa(1)>, L<genrsa(1)>,
  204. L<gendsa(1)>
  205. =head1 HISTORY
  206. The B<-iter> option was added in OpenSSL 1.1.0.
  207. =head1 COPYRIGHT
  208. Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.
  209. Licensed under the OpenSSL license (the "License"). You may not use
  210. this file except in compliance with the License. You can obtain a copy
  211. in the file LICENSE in the source distribution or at
  212. L<https://www.openssl.org/source/license.html>.
  213. =cut