8

I write the Android code to generate RSA key pair and certificate signing request (csr.txt) Here is my csr content:

-----BEGIN CERTIFICATE REQUEST-----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-----END CERTIFICATE REQUEST-----

I found a link can decode my csr file: enter image description here

Then how can I use openssl to export pubic key from this csr file to publickey.pem?

What command can do this?

Thank for advandce.

10

To output only the public key to a local file named publickey.pem:
openssl req -in csr.txt -noout -pubkey -out publickey.pem

You can view the (PEM-encoded) key on the terminal without putting it in a file by dropping the last argument:
openssl req -in csr.txt -noout -pubkey

Note: the -noout option is required, as by default the entire CSR will be placed in the output file, while your question asks for the public key only.

Bonus points: To look inside the BASE64-encoded PEM output and see the actual public key in hex format, pipe it to the pkey function of openssl:
openssl req -in csr.txt -noout -pubkey | openssl pkey -pubin -noout -text

| improve this answer | |
  • 1
    Note: the -noout option is required, as by default the entire CSR will be placed in the output file, while your question asks for the public key only. only answer out there that explains what this flag is doing. Thanks a lot – bi0s.kidd0 Nov 15 '19 at 20:52
3

openssl req -in file.csr -pubkey -out pubkey.pem

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.