05dba8151b
Add new function PEM_write_bio_PrivateKey_traditional() to enforce the use of legacy "traditional" private key format. Add -traditional option to pkcs8 and pkey utilities. Reviewed-by: Matt Caswell <matt@openssl.org>
301 lines
9.3 KiB
Text
301 lines
9.3 KiB
Text
=pod
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=head1 NAME
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pkcs8 - PKCS#8 format private key conversion tool
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=head1 SYNOPSIS
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B<openssl> B<pkcs8>
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[B<-help>]
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[B<-topk8>]
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[B<-inform PEM|DER>]
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[B<-outform PEM|DER>]
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[B<-in filename>]
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[B<-passin arg>]
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[B<-out filename>]
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[B<-passout arg>]
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[B<-iter count>]
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[B<-noiter>]
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[B<-nocrypt>]
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[B<-traditional>]
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[B<-v2 alg>]
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[B<-v2prf alg>]
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[B<-v1 alg>]
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[B<-engine id>]
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[B<-scrypt>]
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[B<-scrypt_N N>]
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[B<-scrypt_r r>]
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[B<-scrypt_p p>]
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=head1 DESCRIPTION
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The B<pkcs8> command processes private keys in PKCS#8 format. It can handle
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both unencrypted PKCS#8 PrivateKeyInfo format and EncryptedPrivateKeyInfo
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format with a variety of PKCS#5 (v1.5 and v2.0) and PKCS#12 algorithms.
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=head1 COMMAND OPTIONS
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=over 4
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=item B<-help>
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Print out a usage message.
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=item B<-topk8>
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Normally a PKCS#8 private key is expected on input and a private key will be
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written to the output file. With the B<-topk8> option the situation is
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reversed: it reads a private key and writes a PKCS#8 format key.
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=item B<-inform DER|PEM>
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This specifies the input format: see L<KEY FORMATS> for more details.
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=item B<-outform DER|PEM>
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This specifies the output format: see L<KEY FORMATS> for more details.
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=item B<-traditional>
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When this option is present and B<-topk8> is not a traditional format private
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key is written.
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=item B<-in filename>
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This specifies the input filename to read a key from or standard input if this
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option is not specified. If the key is encrypted a pass phrase will be
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prompted for.
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=item B<-passin arg>
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the input file password source. For more information about the format of B<arg>
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see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
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=item B<-out filename>
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This specifies the output filename to write a key to or standard output by
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default. If any encryption options are set then a pass phrase will be
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prompted for. The output filename should B<not> be the same as the input
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filename.
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=item B<-passout arg>
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the output file password source. For more information about the format of B<arg>
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see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
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=item B<-iter count>
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When creating new PKCS#8 containers, use a given number of iterations on
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the password in deriving the encryption key for the PKCS#8 output.
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High values increase the time required to brute-force a PKCS#8 container.
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=item B<-nocrypt>
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PKCS#8 keys generated or input are normally PKCS#8 EncryptedPrivateKeyInfo
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structures using an appropriate password based encryption algorithm. With
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this option an unencrypted PrivateKeyInfo structure is expected or output.
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This option does not encrypt private keys at all and should only be used
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when absolutely necessary. Certain software such as some versions of Java
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code signing software used unencrypted private keys.
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=item B<-v2 alg>
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This option sets the PKCS#5 v2.0 algorithm.
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The B<alg> argument is the encryption algorithm to use, valid values include
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B<aes128>, B<aes256> and B<des3>. If this option isn't specified then B<aes256>
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is used.
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=item B<-v2prf alg>
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This option sets the PRF algorithm to use with PKCS#5 v2.0. A typical value
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value would be B<hmacWithSHA256>. If this option isn't set then the default
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for the cipher is used or B<hmacWithSHA256> if there is no default.
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Some implementations may not support custom PRF algorithms and may require
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the B<hmacWithSHA1> option to work.
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=item B<-v1 alg>
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This option indicates a PKCS#5 v1.5 or PKCS#12 algorithm should be used. Some
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older implementations may not support PKCS#5 v2.0 and may require this option.
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If not specified PKCS#5 v2.0 form is used.
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=item B<-engine id>
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specifying an engine (by its unique B<id> string) will cause B<pkcs8>
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to attempt to obtain a functional reference to the specified engine,
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thus initialising it if needed. The engine will then be set as the default
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for all available algorithms.
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=item B<-scrypt>
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uses the B<scrypt> algorithm for private key encryption using default
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parameters: currently N=16384, r=8 and p=1 and AES in CBC mode with a 256 bit
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key. These parameters can be modified using the B<-scrypt_N>, B<-scrypt_r>,
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B<-scrypt_p> and B<-v2> options.
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B<-scrypt_N N> B<-scrypt_r r> B<-scrypt_p p>
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sets the scrypt B<N>, B<r> or B<p> parameters.
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=back
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=head1 KEY FORMATS
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Various different formats are used by the pkcs8 utility. These are detailed
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below.
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If a key is being converted from PKCS#8 form (i.e. the B<-topk8> option is
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not used) then the input file must be in PKCS#8 format. An encrypted
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key is expected unless B<-nocrypt> is included.
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If B<-topk8> is not used and B<PEM> mode is set the output file will be an
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unencrypted private key in PKCS#8 format. If the B<-traditional> option is
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used then a traditional format private key is written instead.
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If B<-topk8> is not used and B<DER> mode is set the output file will be an
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unencrypted private key in traditional DER format.
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If B<-topk8> is used then any supported private key can be used for the input
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file in a format specified by B<-inform>. The output file will be encrypted
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PKCS#8 format using the specified encryption parameters unless B<-nocrypt>
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is included.
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=head1 NOTES
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By default, when converting a key to PKCS#8 format, PKCS#5 v2.0 using 256 bit
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AES with HMAC and SHA256 is used.
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Some older implementations do not support PKCS#5 v2.0 format and require
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the older PKCS#5 v1.5 form instead, possibly also requiring insecure weak
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encryption algorithms such as 56 bit DES.
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The encrypted form of a PEM encode PKCS#8 files uses the following
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headers and footers:
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-----BEGIN ENCRYPTED PRIVATE KEY-----
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-----END ENCRYPTED PRIVATE KEY-----
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The unencrypted form uses:
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-----BEGIN PRIVATE KEY-----
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-----END PRIVATE KEY-----
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Private keys encrypted using PKCS#5 v2.0 algorithms and high iteration
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counts are more secure that those encrypted using the traditional
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SSLeay compatible formats. So if additional security is considered
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important the keys should be converted.
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It is possible to write out DER encoded encrypted private keys in
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PKCS#8 format because the encryption details are included at an ASN1
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level whereas the traditional format includes them at a PEM level.
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=head1 PKCS#5 v1.5 and PKCS#12 algorithms.
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Various algorithms can be used with the B<-v1> command line option,
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including PKCS#5 v1.5 and PKCS#12. These are described in more detail
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below.
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=over 4
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=item B<PBE-MD2-DES PBE-MD5-DES>
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These algorithms were included in the original PKCS#5 v1.5 specification.
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They only offer 56 bits of protection since they both use DES.
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=item B<PBE-SHA1-RC2-64 PBE-MD2-RC2-64 PBE-MD5-RC2-64 PBE-SHA1-DES>
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These algorithms are not mentioned in the original PKCS#5 v1.5 specification
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but they use the same key derivation algorithm and are supported by some
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software. They are mentioned in PKCS#5 v2.0. They use either 64 bit RC2 or
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56 bit DES.
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=item B<PBE-SHA1-RC4-128 PBE-SHA1-RC4-40 PBE-SHA1-3DES PBE-SHA1-2DES PBE-SHA1-RC2-128 PBE-SHA1-RC2-40>
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These algorithms use the PKCS#12 password based encryption algorithm and
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allow strong encryption algorithms like triple DES or 128 bit RC2 to be used.
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=back
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=head1 EXAMPLES
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Convert a private key to PKCS#8 format using default parameters (AES with
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256 bit key and B<hmacWithSHA256>):
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openssl pkcs8 -in key.pem -topk8 -out enckey.pem
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Convert a private key to PKCS#8 unencrypted format:
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openssl pkcs8 -in key.pem -topk8 -nocrypt -out enckey.pem
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Convert a private key to PKCS#5 v2.0 format using triple DES:
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openssl pkcs8 -in key.pem -topk8 -v2 des3 -out enckey.pem
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Convert a private key to PKCS#5 v2.0 format using AES with 256 bits in CBC
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mode and B<hmacWithSHA512> PRF:
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openssl pkcs8 -in key.pem -topk8 -v2 aes-256-cbc -v2prf hmacWithSHA512 -out enckey.pem
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Convert a private key to PKCS#8 using a PKCS#5 1.5 compatible algorithm
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(DES):
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openssl pkcs8 -in key.pem -topk8 -v1 PBE-MD5-DES -out enckey.pem
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Convert a private key to PKCS#8 using a PKCS#12 compatible algorithm
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(3DES):
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openssl pkcs8 -in key.pem -topk8 -out enckey.pem -v1 PBE-SHA1-3DES
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Read a DER unencrypted PKCS#8 format private key:
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openssl pkcs8 -inform DER -nocrypt -in key.der -out key.pem
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Convert a private key from any PKCS#8 encrypted format to traditional format:
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openssl pkcs8 -in pk8.pem -traditional -out key.pem
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Convert a private key to PKCS#8 format, encrypting with AES-256 and with
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one million iterations of the password:
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openssl pkcs8 -in key.pem -topk8 -v2 aes-256-cbc -iter 1000000 -out pk8.pem
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=head1 STANDARDS
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Test vectors from this PKCS#5 v2.0 implementation were posted to the
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pkcs-tng mailing list using triple DES, DES and RC2 with high iteration
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counts, several people confirmed that they could decrypt the private
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keys produced and Therefore it can be assumed that the PKCS#5 v2.0
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implementation is reasonably accurate at least as far as these
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algorithms are concerned.
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The format of PKCS#8 DSA (and other) private keys is not well documented:
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it is hidden away in PKCS#11 v2.01, section 11.9. OpenSSL's default DSA
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PKCS#8 private key format complies with this standard.
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=head1 BUGS
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There should be an option that prints out the encryption algorithm
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in use and other details such as the iteration count.
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=head1 SEE ALSO
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L<dsa(1)>, L<rsa(1)>, L<genrsa(1)>,
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L<gendsa(1)>
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=head1 HISTORY
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The B<-iter> option was added to OpenSSL 1.1.0.
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=head1 COPYRIGHT
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Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the OpenSSL license (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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L<https://www.openssl.org/source/license.html>.
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=cut
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