06-30-2014, 08:57 PM
Okay here is my say on this.
First off all the encrypted messsage is clearly not hexadecimal,
because it seams to use all letters of the alphabet both capital and non capital. furthermore it also uses "+", "/" and "="
I think this is a clear indication of base64 encoding.
But the "=" close to the end confuses me, it should only be on the end.
Added as padding if the message is too short.
Anybody having studied RSA will know that both the private key and the public key consist of 2 parts, the exponent and the modulus. I only see one here. Judging by it size, I think it's the exponent. (also gtaguy confirmed this to me in game.)
He doesn't explicitly state whether he encrypted the message with his public key or his private key. But the public and private exponent are interchangeable, when encrypting data. But only the opposide key can decrypt it. Really what is the public and what is the private is decided when you decide which to use to encrypt.
He says he gives us his private key, so I'm assuming he encrypted it using his public key. I don't think there would be a reason to state it so specificly that he gives us his (incomplete) private key.
I think decrypting is impossible because the encrypted message is not right in the first place. But lets just for the sake of argument assume we had a good encrypted message. Then we still have the question, did he split his message into parts before encrypting and did he just append them all?
I'm assuming he didn't, just because he doesn't state it. He also doesn't state whether he encoded his message base64 before encrypting.
Then the normal way to decrypt it would be :
(encrypted message^private exponent) mod (modulus) = plaintext
Since we don't know the modulus we have a problem.
But we do know something more we know that the modulus is probably greater then the exponent. What we do know for sure is that the public exponent is smaller then the modules. The public exponent is most of the time 65537. Because this makes encryption easier and has some nice properties.
This makes it possible to verify we have the right modulus.
If we had the right modules, we could just decrypt his message.
Then encrypt it again using the public key. If and only if they are the same we have the right exponent.
So in theory we could brute force his modulus if we have a correct encrypted message.
I'm requesting that gtaguy makes his original post more clear.
And corrects his base64 encoding.
For me he doesn't have to give his modulus, but confirming he used 65537 as public exponent would be nice.
-Jmking80
P.s. I'm going to get cracking the moment he updates
Quote:hexa-something i know that much!
First off all the encrypted messsage is clearly not hexadecimal,
because it seams to use all letters of the alphabet both capital and non capital. furthermore it also uses "+", "/" and "="
I think this is a clear indication of base64 encoding.
But the "=" close to the end confuses me, it should only be on the end.
Added as padding if the message is too short.
Anybody having studied RSA will know that both the private key and the public key consist of 2 parts, the exponent and the modulus. I only see one here. Judging by it size, I think it's the exponent. (also gtaguy confirmed this to me in game.)
He doesn't explicitly state whether he encrypted the message with his public key or his private key. But the public and private exponent are interchangeable, when encrypting data. But only the opposide key can decrypt it. Really what is the public and what is the private is decided when you decide which to use to encrypt.
He says he gives us his private key, so I'm assuming he encrypted it using his public key. I don't think there would be a reason to state it so specificly that he gives us his (incomplete) private key.
I think decrypting is impossible because the encrypted message is not right in the first place. But lets just for the sake of argument assume we had a good encrypted message. Then we still have the question, did he split his message into parts before encrypting and did he just append them all?
I'm assuming he didn't, just because he doesn't state it. He also doesn't state whether he encoded his message base64 before encrypting.
Then the normal way to decrypt it would be :
(encrypted message^private exponent) mod (modulus) = plaintext
Since we don't know the modulus we have a problem.
But we do know something more we know that the modulus is probably greater then the exponent. What we do know for sure is that the public exponent is smaller then the modules. The public exponent is most of the time 65537. Because this makes encryption easier and has some nice properties.
This makes it possible to verify we have the right modulus.
If we had the right modules, we could just decrypt his message.
Then encrypt it again using the public key. If and only if they are the same we have the right exponent.
So in theory we could brute force his modulus if we have a correct encrypted message.
I'm requesting that gtaguy makes his original post more clear.
And corrects his base64 encoding.
For me he doesn't have to give his modulus, but confirming he used 65537 as public exponent would be nice.
-Jmking80
P.s. I'm going to get cracking the moment he updates