openssl-pkcs8.pod.in 9.1 KB

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  1. =pod
  2. {- OpenSSL::safe::output_do_not_edit_headers(); -}
  3. =head1 NAME
  4. openssl-pkcs8 - PKCS#8 format private key conversion command
  5. =head1 SYNOPSIS
  6. B<openssl> B<pkcs8>
  7. [B<-help>]
  8. [B<-topk8>]
  9. [B<-inform> B<DER>|B<PEM>]
  10. [B<-outform> B<DER>|B<PEM>]
  11. [B<-in> I<filename>]
  12. [B<-passin> I<arg>]
  13. [B<-out> I<filename>]
  14. [B<-passout> I<arg>]
  15. [B<-iter> I<count>]
  16. [B<-noiter>]
  17. [B<-nocrypt>]
  18. [B<-traditional>]
  19. [B<-v2> I<alg>]
  20. [B<-v2prf> I<alg>]
  21. [B<-v1> I<alg>]
  22. [B<-scrypt>]
  23. [B<-scrypt_N> I<N>]
  24. [B<-scrypt_r> I<r>]
  25. [B<-scrypt_p> I<p>]
  26. {- $OpenSSL::safe::opt_r_synopsis -}
  27. {- $OpenSSL::safe::opt_engine_synopsis -}{- $OpenSSL::safe::opt_provider_synopsis -}
  28. =for openssl ifdef engine scrypt scrypt_N scrypt_r scrypt_p
  29. =head1 DESCRIPTION
  30. This 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> B<DER>|B<PEM>, B<-outform> B<DER>|B<PEM>
  42. The input and formats; the default is B<PEM>.
  43. See L<openssl-format-options(1)> for details.
  44. If a key is being converted from PKCS#8 form (i.e. the B<-topk8> option is
  45. not used) then the input file must be in PKCS#8 format. An encrypted
  46. key is expected unless B<-nocrypt> is included.
  47. If B<-topk8> is not used and B<PEM> mode is set the output file will be an
  48. unencrypted private key in PKCS#8 format. If the B<-traditional> option is
  49. used then a traditional format private key is written instead.
  50. If B<-topk8> is not used and B<DER> mode is set the output file will be an
  51. unencrypted private key in traditional DER format.
  52. If B<-topk8> is used then any supported private key can be used for the input
  53. file in a format specified by B<-inform>. The output file will be encrypted
  54. PKCS#8 format using the specified encryption parameters unless B<-nocrypt>
  55. is included.
  56. =item B<-traditional>
  57. When this option is present and B<-topk8> is not a traditional format private
  58. key is written.
  59. =item B<-in> I<filename>
  60. This specifies the input filename to read a key from or standard input if this
  61. option is not specified. If the key is encrypted a pass phrase will be
  62. prompted for.
  63. =item B<-passin> I<arg>, B<-passout> I<arg>
  64. The password source for the input and output file.
  65. For more information about the format of B<arg>
  66. see L<openssl-passphrase-options(1)>.
  67. =item B<-out> I<filename>
  68. This specifies the output filename to write a key to or standard output by
  69. default. If any encryption options are set then a pass phrase will be
  70. prompted for. The output filename should B<not> be the same as the input
  71. filename.
  72. =item B<-iter> I<count>
  73. When creating new PKCS#8 containers, use a given number of iterations on
  74. the password in deriving the encryption key for the PKCS#8 output.
  75. High values increase the time required to brute-force a PKCS#8 container.
  76. =item B<-nocrypt>
  77. PKCS#8 keys generated or input are normally PKCS#8 EncryptedPrivateKeyInfo
  78. structures using an appropriate password based encryption algorithm. With
  79. this option an unencrypted PrivateKeyInfo structure is expected or output.
  80. This option does not encrypt private keys at all and should only be used
  81. when absolutely necessary. Certain software such as some versions of Java
  82. code signing software used unencrypted private keys.
  83. =item B<-v2> I<alg>
  84. This option sets the PKCS#5 v2.0 algorithm.
  85. The I<alg> argument is the encryption algorithm to use, valid values include
  86. B<aes128>, B<aes256> and B<des3>. If this option isn't specified then B<aes256>
  87. is used.
  88. =item B<-v2prf> I<alg>
  89. This option sets the PRF algorithm to use with PKCS#5 v2.0. A typical value
  90. value would be B<hmacWithSHA256>. If this option isn't set then the default
  91. for the cipher is used or B<hmacWithSHA256> if there is no default.
  92. Some implementations may not support custom PRF algorithms and may require
  93. the B<hmacWithSHA1> option to work.
  94. =item B<-v1> I<alg>
  95. This option indicates a PKCS#5 v1.5 or PKCS#12 algorithm should be used. Some
  96. older implementations may not support PKCS#5 v2.0 and may require this option.
  97. If not specified PKCS#5 v2.0 form is used.
  98. =item B<-scrypt>
  99. Uses the B<scrypt> algorithm for private key encryption using default
  100. parameters: currently N=16384, r=8 and p=1 and AES in CBC mode with a 256 bit
  101. key. These parameters can be modified using the B<-scrypt_N>, B<-scrypt_r>,
  102. B<-scrypt_p> and B<-v2> options.
  103. =item B<-scrypt_N> I<N>, B<-scrypt_r> I<r>, B<-scrypt_p> I<p>
  104. Sets the scrypt I<N>, I<r> or I<p> parameters.
  105. {- $OpenSSL::safe::opt_r_item -}
  106. {- $OpenSSL::safe::opt_engine_item -}
  107. {- $OpenSSL::safe::opt_provider_item -}
  108. =back
  109. =head1 NOTES
  110. By default, when converting a key to PKCS#8 format, PKCS#5 v2.0 using 256 bit
  111. AES with HMAC and SHA256 is used.
  112. Some older implementations do not support PKCS#5 v2.0 format and require
  113. the older PKCS#5 v1.5 form instead, possibly also requiring insecure weak
  114. encryption algorithms such as 56 bit DES.
  115. Private keys encrypted using PKCS#5 v2.0 algorithms and high iteration
  116. counts are more secure that those encrypted using the traditional
  117. SSLeay compatible formats. So if additional security is considered
  118. important the keys should be converted.
  119. It is possible to write out DER encoded encrypted private keys in
  120. PKCS#8 format because the encryption details are included at an ASN1
  121. level whereas the traditional format includes them at a PEM level.
  122. =head1 PKCS#5 V1.5 AND PKCS#12 ALGORITHMS
  123. Various algorithms can be used with the B<-v1> command line option,
  124. including PKCS#5 v1.5 and PKCS#12. These are described in more detail
  125. below.
  126. =over 4
  127. =item B<PBE-MD2-DES PBE-MD5-DES>
  128. These algorithms were included in the original PKCS#5 v1.5 specification.
  129. They only offer 56 bits of protection since they both use DES.
  130. =item B<PBE-SHA1-RC2-64>, B<PBE-MD2-RC2-64>, B<PBE-MD5-RC2-64>, B<PBE-SHA1-DES>
  131. These algorithms are not mentioned in the original PKCS#5 v1.5 specification
  132. but they use the same key derivation algorithm and are supported by some
  133. software. They are mentioned in PKCS#5 v2.0. They use either 64 bit RC2 or
  134. 56 bit DES.
  135. =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>
  136. These algorithms use the PKCS#12 password based encryption algorithm and
  137. allow strong encryption algorithms like triple DES or 128 bit RC2 to be used.
  138. =back
  139. =head1 EXAMPLES
  140. Convert a private key to PKCS#8 format using default parameters (AES with
  141. 256 bit key and B<hmacWithSHA256>):
  142. openssl pkcs8 -in key.pem -topk8 -out enckey.pem
  143. Convert a private key to PKCS#8 unencrypted format:
  144. openssl pkcs8 -in key.pem -topk8 -nocrypt -out enckey.pem
  145. Convert a private key to PKCS#5 v2.0 format using triple DES:
  146. openssl pkcs8 -in key.pem -topk8 -v2 des3 -out enckey.pem
  147. Convert a private key to PKCS#5 v2.0 format using AES with 256 bits in CBC
  148. mode and B<hmacWithSHA512> PRF:
  149. openssl pkcs8 -in key.pem -topk8 -v2 aes-256-cbc -v2prf hmacWithSHA512 -out enckey.pem
  150. Convert a private key to PKCS#8 using a PKCS#5 1.5 compatible algorithm
  151. (DES):
  152. openssl pkcs8 -in key.pem -topk8 -v1 PBE-MD5-DES -out enckey.pem
  153. Convert a private key to PKCS#8 using a PKCS#12 compatible algorithm
  154. (3DES):
  155. openssl pkcs8 -in key.pem -topk8 -out enckey.pem -v1 PBE-SHA1-3DES
  156. Read a DER unencrypted PKCS#8 format private key:
  157. openssl pkcs8 -inform DER -nocrypt -in key.der -out key.pem
  158. Convert a private key from any PKCS#8 encrypted format to traditional format:
  159. openssl pkcs8 -in pk8.pem -traditional -out key.pem
  160. Convert a private key to PKCS#8 format, encrypting with AES-256 and with
  161. one million iterations of the password:
  162. openssl pkcs8 -in key.pem -topk8 -v2 aes-256-cbc -iter 1000000 -out pk8.pem
  163. =head1 STANDARDS
  164. Test vectors from this PKCS#5 v2.0 implementation were posted to the
  165. pkcs-tng mailing list using triple DES, DES and RC2 with high iteration
  166. counts, several people confirmed that they could decrypt the private
  167. keys produced and therefore, it can be assumed that the PKCS#5 v2.0
  168. implementation is reasonably accurate at least as far as these
  169. algorithms are concerned.
  170. The format of PKCS#8 DSA (and other) private keys is not well documented:
  171. it is hidden away in PKCS#11 v2.01, section 11.9. OpenSSL's default DSA
  172. PKCS#8 private key format complies with this standard.
  173. =head1 BUGS
  174. There should be an option that prints out the encryption algorithm
  175. in use and other details such as the iteration count.
  176. =head1 SEE ALSO
  177. L<openssl(1)>,
  178. L<openssl-dsa(1)>,
  179. L<openssl-rsa(1)>,
  180. L<openssl-genrsa(1)>,
  181. L<openssl-gendsa(1)>
  182. =head1 HISTORY
  183. The B<-iter> option was added in OpenSSL 1.1.0.
  184. The B<-engine> option was deprecated in OpenSSL 3.0.
  185. =head1 COPYRIGHT
  186. Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.
  187. Licensed under the Apache License 2.0 (the "License"). You may not use
  188. this file except in compliance with the License. You can obtain a copy
  189. in the file LICENSE in the source distribution or at
  190. L<https://www.openssl.org/source/license.html>.
  191. =cut