Operation request: RSA Key Modulus - Githubissues

gchq / CyberChef

The Cyber Swiss Army Knife - a web app for encryption, encoding, compression and data analysis

https://gchq.github.io/CyberChef

Apache License 2.0

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Operation request: RSA Key Modulus #1443

Open mddeff opened 1 year ago

mddeff commented 1 year ago

Summary

Would love to have the ability to calculate an RSA key's modulus. Very helpful in verifying the private key matches the public (x509) cert. Example openssl invocation:

openssl rsa -noout -modulus -in rsa.key

The Parse X.509 certificate already provides the public cert modulus, and in theory a well-crafted recipe would be able to compare both?

Example Input

-----BEGIN PRIVATE KEY-----
someRAndoMkeyMATerial
-----END PRIVATE KEY-----

Example Output

ABCDEF0123456789......

mikecat commented 1 year ago

If what you want is in the output, I guess it can be extracted via "Regular expression" with Output format ~~"Highlight matches"~~ "List capture groups".

I tried to create the recipe, but The "Parse X.509 certificate" operation yielded only this error for all of the 4 Input formats:

Parse X.509 certificate - TypeError in https://gchq.github.io/CyberChef/modules/PublicKey.js on line 2.<br><br>Message: t is null

Here is my input:

-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----

This data is created only for this issue via these commands:

openssl genrsa -out hoge.pem
openssl pkcs8 -in hoge.pem -topk8 -nocrypt -out meow.pem

How did you get the public cert modulus via "Parse X.509 certificate"?

mikecat commented 1 year ago

I found it. The operation is for parsing certificate, so a certificate should be provided as the input.

Example input:

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

Command to generate:

echo -e "hoge\nhoge\n\n\n\n\n\n\n\n\n\n" | openssl req -x509 -days 365 -newkey rsa:512 -keyout key.pem -out cert.pem
cat cert.pem

Recipe:

Parse X.509 certificate, 2 more - CyberChef

Example output:

9c1bef88709076fa614f6dab2b4011284936c5d33fd63267cd56669d89319af1e461fe935e69a0c0f9273f358199f622dcec4efa75395a774daa609950c2d06b

mikecat commented 1 year ago

Ah, your request is "the modulus can be extracted from a certificate, how to extract one from a private key?"?

Then...

Use "PEM to Hex" and "Parse ASN.1 hex string" to split the key into elements
Extract the 3rd INTEGER.
Remove trailing zero.

PEM to Hex, 5 more - CyberChef