How to extract the public key from an RSA key file using OpenSSL "rsa" command?

If you want to extract the public key out from an RSA key file (private key an public key), you can use the OpenSSL "rsa -pubout" command as shown below:

C:\Users\fyicenter>\local\openssl\openssl.exe

OpenSSL> rsa -in my_rsa.key -pubout -out my_rsa_pub.key
writing RSA key

OpenSSL> exit

C:\Users\fyicenter>type my_rsa_pub.key
-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAx1SQU1GfsBNB6XU2nqrw
IHm1ImXPAcsInQNfhFcpzpku3Kmm0LpDZF1oqkqLNLlh0qVIIlfuMNnVNLAozbUb
aJalFUdSGPAVl7jFRZxpDai+d4U2we14MO3kTwy7H3ZeRKzWklL2FCeKo2c20gzF
OfxdePwSx9lBT7efFNc5NHRPdPbP/e1Zx1VqB8wAKTgRwafQmFfYUbbk2Cc5ftZ8
yhWc43+2qWzhWm6Ig8knbapPLMPw6bFzwD+ck+6d7zbCG++NrBuXH858iDJfzLgr
wic7fW0cRiF+yBpiTmAw6G9HH0CQu8HNBgMfXZIuYjZER4MObmqSGiRTyN9mEFtS
WwIDAQAB
-----END PUBLIC KEY-----

Options used in this command are:

• "-in my_rsa.key" - Read the RSA key file from: C:\Users\fyicenter\my_rsa.key
• "-pubout" - Extract the public key out of the RSA key file
• "-out my_rsa_pub.key" - Save the public key in a file with no password protection.

⇒ OpenSSL "rsa -pubin" - View RSA Public Key

⇐ OpenSSL "rsa -text" - Print RSA Key in Text

⇑ OpenSSL "genrsa" and "rsa" Commands

⇑⇑ OpenSSL Tutorials