Feb 11, 2019 SSH private and public key generator in pure Ruby (RSA & DSA) - bensie/sshkey. SSH private and public key generator in pure Ruby (RSA & DSA) - bensie/sshkey. Skip to content. Features → Code review.
I'm new to SSL/TLS. I'm trying to generate the public and private key using gen_key application that came with mbed TLS. I found this link below:
https://tls.mbed.org/kb/cryptography/rsa-key-pair-generator
Following the instruction above, I typed:
./gen_key type=rsa rsa_keysize=4096 filename=private.key format=pem
Once the program finished, I found that I have private.key file, but could not find private.pub file any where. Please let me know where the public key file is, or how to generate the public key.
Thanks,Trip
Please ignore. I figured it out.
Hello Trip,
Maybe it is nice if you post to the forum what you did to figure it out, when someone has a similar question they don't have to post it to the forum again. Knowledge sharing is all this forum should be about!
Thanks.
Regards,Mark
gen_key does not generate both public and private key, it only generates the private key. Using the private key, we would request a certificate. The public key is then created in the certificate. At least that's my understanding.
Hi Trip,
The application mbedtls/programs/pkey/gen_key is a utility that can help to easily generate EC or RSA keys in PEM or DER format. This application will only output a private key file, and the public key can be computed by simply decoding information and doing the necessary arithmetic.
To generate both private and public key files in a specific format, an application can be written using the mbed TLS library. Alternatively, if the format is not important, the tool at programs/pkey/rsa_genkey generates both public and private 2048-bit RSA key files in plain text format. This rsa_genkey is also simpler and can be used as a starting point for software with specific requirements.
I hope this information is helpful.
Kind regards,Andres AG,mbed TLS Team Member
Thanks, Andres. Certainly very helpful information.
Hi Andres,
Thank you for information. I have one question.
Can we generate the public and private key of 1024 bits by using rsa_genkey.c file.I will wait for your valuable reply.
Thanks & Regards,Abhishek Shah
Hi Abhishek,rsa_genkey is a sample application to show how to generate an rsa key pair. In order for you to generate a 1024 rsa key, all you need to do is modify in rsa_genkey.c the value of KEY_SIZE from 2048 to 1024.
Having said that, note that RSA with 1024bit key size has been deprecated and considered now as non-secure, so it is not recommended to use this key size.
Regards,
mbed TLS Team member
Ron
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I am a firm believer that JavaScript will eventually be the ubiquitous coding languageof the future. Although there are many objections to this statement, I don’t thinkanyone can argue that it is the best poised for ubiquity considering itis now used in both server side (node.js) and obviously clientside open web standards. And considering that this language did start out as a ‘toy’language, I am often amazing at how far it has come in maturity in recent years. Thereis an area where I am most amazed at its progression, and that is with Encryption. Foryears, this area was pretty much dominated by the C and C++ languages (to which I amalso a seasoned developer in), but now that JavaScript has made its way to the server,it is becoming recognized as a potential contender to this domination.
Much of this recognition should be directed toward the fantastic work of Tom Wuof Standford. It was his work with the JSBN library that really opened peoples eyesto the effectiveness of JavaScript in the field of encryption. However, there was justminor drawback to his work… The only real way to utilize his library is to have a fullunderstanding behind the equations of encryption, which comes at as a huge hurtle consideringthe industry has been spoiled with the ease of use of the OpenSSL library generation ofstandardized keys used in the encryption. In this system, there is really only two thingsto worry about… The Public Key and the Private Key, usedfor encryption and decryption respectively. But in order to use Tom Wu’slibrary, you must learn how to utilize eight different variables to the encryption equations!I recognized this as a perfect opportunity to create a simple wrapper library around his library thatsimply speaks in terms of the Public and Private keyseveryone is familiar with. Of course I found other libraries out there that claim to do the same, butwhat I couldn’t find in these libraries was a simple wrapper around this library that basically usesTom’s library practically untouched, but simply adds a wrapper to provide parsing of actual Private and Public key-pairsgenerated with OpenSSL. Enter JSEncrypt.
Download
Go to https://github.com/travist/jsencrypt to download this library.
Website & Demo
How to use this library.
This library should work hand-in-hand with openssl. With that said, here is how to use this library.
- Within your terminal (Unix based OS) type the following.
- This generates a private key, which you can see by doing the following…
- You can then copy and paste this in the Private Key section of within index.html.
- Next, you can then get the public key by executing the following command.
- You can see the public key by typing…
- Now copy and paste this in the Public key within the index.html.
- Now you can then convert to and from encrypted text by doing the following in code.
Here is a demo… http://travistidwell.com/jsencrypt/demo/index.html
Other Information
Private Key Encryption
This library heavily utilizes the wonderful work of Tom Wu found at http://www-cs-students.stanford.edu/~tjw/jsbn.
This jsbn library was written using the raw variables to perform encryption. This is great for encryption, but most private keys use a Private Key in the PEM format seen below.
1024 bit RSA Private Key in Base64 Format
This library simply takes keys in the following format, and translates it to those variables needed to perform the encryptions used in Tom Wu’s library.
Here are some good resources to investigate further.
What Is Public Key
With this information, we can translate a private key format to the variables required with the jsbn library from Tom Wu by using the following mappings.