The rsa command processes RSA keys. They can be converted between various forms and their components printed out.
This command uses the traditional SSLeay compatible format for private key encryption: newer applications should use the more secure PKCS#8 format using the pkcs8 utility.
specifies the input format. The DER option uses an ASN1 DER encoded form compatible with the PKCS#1 RSAPrivateKey or SubjectPublicKeyInfo format. The PEM form is the default format: it consists of the DER format base64 encoded with additional header and footer lines. On input PKCS#8 format private keys are also accepted. The NET form is a format is described in the NOTES section.
specifies the output format, the options have the same meaning as the
specifies the input file name to read a key from or standard input if this option is not specified. If the key is encrypted a pass phrase will be prompted for.
specifies the output file name to write a key to or standard output if this option is not specified. If any encryption options are set then a pass phrase will be prompted for. The output file name should not be the same as the input file name.
uses the modified NET algorithm used with some versions of Microsoft IIS and SGC keys.
-des| -des3| -idea
These options encrypt the private key with the DES, triple DES, or the IDEA ciphers respectively before outputting it. A pass phrase is prompted for. If none of these options is specified the key is written in plain text. This means that using the rsa utility to read in an encrypted key with no encryption option can be used to remove the pass phrase from a key, or by setting the encryption options it can be use to add or change the pass phrase. These options can only be used with PEM format output files.
prints out the various public or private key components in plain text in addition to the encoded version.
prevents output of the encoded version of the key.
prints out the value of the modulus of the key.
checks the consistency of an RSA private key.
by default a private key is read from the input file: with this option a public key is read instead.
by default a private key is output: with this option a public key will be output instead. This option is automatically set if the input is a public key.
The PEM private key format uses the header and footer lines:
-----BEGIN RSA PRIVATE KEY----- -----END RSA PRIVATE KEY-----
The PEM public key format uses the header and footer lines:
-----BEGIN PUBLIC KEY----- -----END PUBLIC KEY-----
The NET form is a format compatible with older Netscape servers and Microsoft IIS .key files, this uses unsalted RC4 for its encryption. It is not very secure and so should only be used when necessary.
Some newer version of IIS have additional data in the exported .key
files. To use these with the utility view the file with a binary editor
and look for the string "private-key", then trace back to the byte
sequence 0x30, 0x82 (this is an ASN1 SEQUENCE). Copy all the data
from this point onwards to another file and use that as the input
to the rsa utility with the
To remove the pass phrase on an RSA private key:
openssl rsa -in key.pem -out keyout.pem
To encrypt a private key using triple DES:
openssl rsa -in key.pem -des3 -out keyout.pem
To convert a private key from PEM to DER format:
openssl rsa -in key.pem -outform DER -out keyout.der
To print out the components of a private key to standard output:
openssl rsa -in key.pem -text -noout
To just output the public part of a private key:
openssl rsa -in key.pem -pubout -out pubkey.pem
The command line password arguments don't currently work with NET format.
There should be an option that automatically handles .key files, without having to manually edit them.
PTC MKS Toolkit for System Administrators
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PTC MKS Toolkit for Interoperability
PTC MKS Toolkit for Professional Developers
PTC MKS Toolkit for Professional Developers 64-Bit Edition
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PTC MKS Toolkit for Enterprise Developers 64-Bit Edition
PTC MKS Toolkit 10.1 patch 1 Documentation Build 2.