RSA output length...

[Lindon]

So I use the RSA functionality to encrypt my serial numbers. This results in a long value like this:

1a13b5c24f1dc767cc351a8a587ae939c17e0f07c1582d148c5faa3aba4abf1fb7df1bb29b280d6b5813896801cb8e27df681217b99ce869e3ee1d0be3962a1e

and everything works well. But....

I have a distributor who's system cannot accept serial keys longer that 32-characters. Now no matter how smart or dumb we might think this is they don't see to be willing to change it, so....

Is there a way for me to use RSA and generate a shorter result? Even if this means using a less secure RSA key-pair?

[Casmat]

@Lindon if you want generate a shorter key, you’ll have to use less bits, but the less bits, the worse the encryption, and the lower bits one uses, the security exponentially decreases. The least I’d recommend going for is 256 bit, but it’ll crack under good brute force, use any less, and it’ll be an easy task for anyone. You can use this:
https://www.mobilefish.com/services/rsa_key_generation/rsa_key_generation.php
To see the different lengths at different bits easier.
The best of both worlds in this case would be to use a different encryption altogether, but if you need rsa keys, then using lower bits is the answer

[Lindon]

@Casmat said in RSA output length...:

@Lindon if you want generate a shorter key, you’ll have to use less bits, but the less bits, the worse the encryption, and the lower bits one uses, the security exponentially decreases. The least I’d recommend going for is 256 bit, but it’ll crack under good brute force, use any less, and it’ll be an easy task for anyone. You can use this:
https://www.mobilefish.com/services/rsa_key_generation/rsa_key_generation.php
To see the different lengths at different bits easier.
The best of both worlds in this case would be to use a different encryption altogether, but if you need rsa keys, then using lower bits is the answer

thanks I went to look at the page you pointed to - its less than intuituve...

hmm..

[Casmat]

@Lindon good catch haha, meant to give this: https://asecuritysite.com/rsa/rsac it goes down to 60 bits, just look at the cipher part

[Lindon]

@Casmat said in RSA output length...:

@Lindon good catch haha, meant to give this: https://asecuritysite.com/rsa/rsac it goes down to 60 bits, just look at the cipher part

thanks - sorta interesting - but not really any use to me, I need an output thats 32 chars long...

[Casmat]

@Lindon yup, you can get shorter keys, have to use software though, but not at all worth the hassle