1
vote
3answers
558 views

Is there an asymmetric encryption that works in a reverse way of RSA (encrypt using private key and decrypt using public key)? [duplicate]

I'm writing a program that needs to receive an encrypted message from the server and decrypt it on the client. The problem in this case, is to prevent the client from being able to re-transmit ...
-1
votes
1answer
1k views

RSA encryption with private key, decryption with public key (again) [duplicate]

First of all let me point out that I am aware of all the theory behind asymmetric encryption and signing, and other related areas like signcryption, etc. It seems that mathematically it is possible to ...
2
votes
0answers
259 views

How do I encrypt with the private key? [duplicate]

Possible Duplicate: RSA encryption with private key and decryption with a public key This wording is creeping everywhere (e.g. there): "I encrypt with the private key" and even sometimes, "I ...
10
votes
3answers
2k views

Asymmetry between public key and private key: digital signatures use the private key for “encryption”?

I have a misunderstanding concerning public key cryptography...would be very helpful if you answer the questions... Digital signatures: You use your private key for "encryption" and they use your ...
7
votes
1answer
4k views

Is a known plaintext, ciphertext, and public-key a viable attack on RSA?

Assume Alice and Bob are using RSA to create a common session key and Cindy is listening, attempting to obtain the session key. Alice and Bob each have their public- and private-key pairs ($\left[...
3
votes
2answers
2k views

RSA: Is it secure to use the private key to encrypt and the public key to decrypt?

This may sound weird: What if I don't let others know my public key, then use my private key to encrypt, and the public key to decrypt? Is this secure? Let me explain a little bit: Common usuage: use ...
5
votes
2answers
5k views

How to verify the integrity of RSA encrypted messages?

I need to encrypt messages using PublicKeyCrypto and send it to the server, where the message should be decrypted. I'm aware of the Padding Oracle Attack and want to apply a server side integrity ...
3
votes
2answers
2k views

Encryption with private key?

we normally always encrypt by public key and decrypt with private key. If i encrypt with private key, then its still secure as normal PKI ? i mean known-plain-text will not take private key on the ...
4
votes
2answers
731 views

Can I save space for short messages by using encryption with private key instead of a signature?

Let's say I have a message, a Private Key and a Public Key. Normally if you want to see if the message is unaltered and is from the sender you would have the message part + signature part, which you ...
3
votes
2answers
526 views

Is it possible to decrypt a ciphertext with a different private key?

In public key cryptosystem, there are often two keys (pub and pri) and two functions (Enc ...
2
votes
2answers
216 views

Securely generating auth tokens

(Disclaimer: I'm an experienced server-side Java programmer, but with little crypto experience.) Objective: I've got a login server which, given a login+password pair, should issue a unique auth ...