Generally for signing a message, its recommended to sign the hash of the message payload using sender's private key and the recipient should decrypt using sender's public key and validate if hash is correct.
I would like to know what will go wrong if i sign using recipients public key and recipient can decrypt using his private key ( like how payload encryption happens ).
I am new to signing & encryption.I could not find a convincing answer.
If you want to sign a message, you have to use your private key, as this key is obviously private and no one else can sign a message with this key. So everybody can prove with your public key, that you have signed the message, cause no one else can have your private key to sign the message.
On the other hand, 'signing' a message with the public key of the receiver is senseless. The key is public, everyone could have 'sign' this message, so the receiver has no way to prove that your were actually sending this message.
What you can do with a public key of a sender is to encrypt a message. No one else than the receiver will be able to decrypt it, as this will require the private key of the receiver. But signing a message makes no sense.
I am able to wrap a aes key using aes key.
Can i wrap a private or public key with aes key during get operation of kmip ?
One of my client is asking CA Certified Public Key for Encryption/Decryption purpose. And I am not sure how to provide it to them.
Yes, You can reach the Public/Private Key providers to get the key pair (for eg: SSL.com but i am not sure which one is good.)Public key - can be shared with every one but keep the private key as a secret. The information encrypted by your public key can be decrypted only with your private key.
There is some algorithm which signs with a private key and verifies with a public key.
Private and public keys are created in pairs.
Assume we have 2 pairs of private and public keys.
Is there a way to combine two private keys to one private key priv_comb, so that the produced signature S, computed with this priv_comb, could be verified with either of those two public keys?
Or does this make sense at all?
I heard that you can use a private key to encrypt data as a method for digital signing. In other words you can encrypt a message with your private key.
In the text they always seem to say only the public key can encrypt and the private key can decipher the text.
I'm assuming this is a bad choice of words. Is it true that a single instance of a key can do only one or the other, but which key is public or private is not a matter of it's function, but of it's distribution or lack thereof.
For a beginner, the terminology is confusing. RSA can be used for 2 distinct crypto functions: data encryption and digital signatures.
For data encryption, you encrypt data using the recipient's public key; they decrypt it using their private key. Note that due to various limitations of RSA, the "data" that is encrypted and decrypted is usually just a key for a symmetric algorithm.
For digital signatures, you sign the data using your private key; they verify the signature over the data using your public key. Again, various limitations of RSA mean that what is actually operated on by the RSA algorithm is normally a secure hash of the data.
Sometimes the signing operation is called "encrypting with the private key", and the verifying operation is called "decrypting with the public key". I think this just confuses people so I always prefer the terms signing and verifying in this context. Furthermore, "encrypt" and "decrypt" make no sense for other signature algorithms like DSA and ECDSA.
You CAN generate public key from private key.
You CAN'T generate private key from public key (well, you might can, but this is extremely computationally expensive).
That is the difference between the two. They are NOT interchangeable (so, for instance, you SHOULD NOT publish your private key, and keep public key to yourself) because of the way how the algorithms works.
Take for instance RSA. The algorithm base is the problem of integer factorization. You choose two big integers p and q and multiply them to get n = p*q. Then you create public and private key:
Public key: (n, e)
Private key: (p, q, d)
Then:
It is easy to calculate public key from private key:
n = p*q
e = d^(-1) mod φ(n), where φ(n) = (p-1)(q-1)
It is hard to calculate private key from public key - it requires factorization of n to get p and q, which is extremely hard if p and q are big enough.
You release your encryption key to the public, and keep your decryption key private. That way anyone can send you encrypted data that only you can decrypt.
If you did it the other way around, then you would be the only one able to encrypt your data, but anyone could decrpyt it. That makes no sense. If everyone can decrypt your message you might as well send it unencrypted. There is no point encrypted a message and then making the decryption key public.
There are two types encryption one is symmetric another one is asymmetric .In symmetric the key used to encrypt and decrypt is the same . in asymmetric the key used to encrypt is public key and decrypt is private key ..
all works on the principle of a secrecy of the key .In Digital signing commonly used as a part of SSL / TLS protocols uses the asymmetric encryption for the authentication and sharing of the master key which is used further for encrypting the communication line.