To decrypt a message using a public key, the recipient must have the corresponding private key. The sender encrypts the message using the recipient's public key, which can only be decrypted with the recipient's private key. This ensures that only the intended recipient can read the message.
RSA decryption using a public key involves the recipient using the public key provided by the sender to decrypt the encrypted message. The recipient uses the public key to raise the ciphertext to the power of the public exponent, and then takes the result modulo the public modulus to obtain the original plaintext message.
Public key cryptography always works the same way: Encryption is done with the public key, decryption done with the private key. It is not possible to decrypt anything with the public key (otherwise the whole system would crash down). The only time it's done the other way is for message authentication, where only a digest of a message is encrypted and can be verified (not decrypted) using the public key.
When you reference a "public key" you are implying that the file has been encrypted using "asymmetric cryptography". In asymmetric cryptography, encryption and decryption depend on a key PAIR. The user retains their private key and publishes their public key. Anyone can encrypt a file using the user's public key and send it to them. The only person who should be able to decrypt a file encrypted with that public key is the holder of the private key - which, unless the user has made the mistake of sharing their private key - means that only the original user can decrypt the messages sent to them. Most of the asymmetric encryption algorithms use pretty much the same method to decrypt that was used to encrypt, but use the "other" key from the key pair. Messages encrypted using the private key can only be decrypted using the public key - which provides some authentication that the message indeed came from the holder of the private key. Messages encrypted using the public key can only be decrypted by the holder of the private key, so messages sent to them should be secure.
The exact mathematics of the encryption differ depending on the algorithm used, but in principle, this is how it works. An algorithm is used to generate a pair of keys that are related mathematically. In many cases they are factors of a very large number. One of the keys is the Public key, which is published to a key registry. The other is the Private key which is held by the owner alone. The important thing is that it is supposed to be impossible to derive the Private key from the Public key. When the owner wants to send a message, the use the Private key to encrypt it or to sign it. Since only the corresponding Public key can decrypt it, that establishes that the sender is who they say they are (because only they should have the Private key). If the sender used their Private key to sign the message, the receiver can use the Public key verify that the message has not been tampered with. On the flip side, some can encrypt a message to the owner of the Private key by using that person's Public key. Only the holder of the Private key can decrypt the message. This can provide confidentiality. Two correspondents can establish secure communications by using each others Public keys to encrypt their messages. Often the public key is deposited with a trusted Certificate Authority. Assuming the user trusts the key repository, they can use them to authenticate the key they are using as belonging to the person it is supposed to belong to. To get more details on the mathematics of encryption and decrption using Public Key Encryption, aka asymmetric encryption. Do a web search for the particular algorithm involved, be it SSH, PGP, TLS, or some other protocol.
When one key is used for encryption and a different key is used for decryption this is call asymmetric cryptography. A good example of this is PGP (pretty good privacy). PGP is used to secure email. It accomplishes this by generating a pair of keys for each user. After the keys have been generated each user shares one key their public key and keeps their privet key secret. When someone wants to email a person who is using PGP they encrypt their message with the recipient's public key. This ensures that the message cannot be snooped on during transit and that only the person who has the corresponding privet key can decrypt the message.
RSA decryption using a public key involves the recipient using the public key provided by the sender to decrypt the encrypted message. The recipient uses the public key to raise the ciphertext to the power of the public exponent, and then takes the result modulo the public modulus to obtain the original plaintext message.
Public key cryptography always works the same way: Encryption is done with the public key, decryption done with the private key. It is not possible to decrypt anything with the public key (otherwise the whole system would crash down). The only time it's done the other way is for message authentication, where only a digest of a message is encrypted and can be verified (not decrypted) using the public key.
When you reference a "public key" you are implying that the file has been encrypted using "asymmetric cryptography". In asymmetric cryptography, encryption and decryption depend on a key PAIR. The user retains their private key and publishes their public key. Anyone can encrypt a file using the user's public key and send it to them. The only person who should be able to decrypt a file encrypted with that public key is the holder of the private key - which, unless the user has made the mistake of sharing their private key - means that only the original user can decrypt the messages sent to them. Most of the asymmetric encryption algorithms use pretty much the same method to decrypt that was used to encrypt, but use the "other" key from the key pair. Messages encrypted using the private key can only be decrypted using the public key - which provides some authentication that the message indeed came from the holder of the private key. Messages encrypted using the public key can only be decrypted by the holder of the private key, so messages sent to them should be secure.
The exact mathematics of the encryption differ depending on the algorithm used, but in principle, this is how it works. An algorithm is used to generate a pair of keys that are related mathematically. In many cases they are factors of a very large number. One of the keys is the Public key, which is published to a key registry. The other is the Private key which is held by the owner alone. The important thing is that it is supposed to be impossible to derive the Private key from the Public key. When the owner wants to send a message, the use the Private key to encrypt it or to sign it. Since only the corresponding Public key can decrypt it, that establishes that the sender is who they say they are (because only they should have the Private key). If the sender used their Private key to sign the message, the receiver can use the Public key verify that the message has not been tampered with. On the flip side, some can encrypt a message to the owner of the Private key by using that person's Public key. Only the holder of the Private key can decrypt the message. This can provide confidentiality. Two correspondents can establish secure communications by using each others Public keys to encrypt their messages. Often the public key is deposited with a trusted Certificate Authority. Assuming the user trusts the key repository, they can use them to authenticate the key they are using as belonging to the person it is supposed to belong to. To get more details on the mathematics of encryption and decrption using Public Key Encryption, aka asymmetric encryption. Do a web search for the particular algorithm involved, be it SSH, PGP, TLS, or some other protocol.
In public key cryptography there are two parts: 1) secret part 2) public part ,in order for p1 to send p2 a message ,p1 first need to obtain p2's public key and using this key encrypts the message then p2 using his secret key decrypts the message. And in private key cryptograhy there is only one key so in order for p1 to send a message to p2, p1 should firstly ask p2 for his key then encrypt the message using that key and then p2 uses the same key to decrypt the message.
PGP (Pretty Good Privacy) encryption works by using a combination of symmetric and asymmetric encryption techniques. When a user wants to send a secure message, PGP generates a random symmetric key to encrypt the message. This symmetric key is then encrypted using the recipient's public key before sending the message. The recipient can use their private key to decrypt the symmetric key, which can then be used to decrypt the original message.
How data encrypt and decrypt from PC to PC using micro controller?
It depends on how you apply the term "secret key encryption". In one sense "Secret key encryption" refers to using symmetric keys - both parties have the key and must keep it secret in order to protect the confidentiality of the communication. Usually the process that was used to encrypt the original message can be decrypted by repeating the encryption process with the original secret key. This should provide for confidentiality, non-repudiation, and validation since only the holders of the shared secret key should be able to successfully encrypt and decrypt the messages. In contrast to the symmetric key encryption, Public Key encryption uses two keys in the encryption/decryption process. Anything encrypted with one key can be decrypted with the other key. The "public key" is published for everyone to access. The "private key" is kept by the owner and not made available to the world. The encryption of the original message using one key can be "undone" only by using the other key. Using the public key on a message already encrypted with the public key only results in an even more jumbled and unintelligible mess. The end result is that is someone encrypts a message with their private key, only their public key can be used to decrypt it, thus verifying the source of the message. Any message encrypted using the public key can only be decrypted with the private key, thus providing confidentiality. If two users want to use asymmetric encryption to communicate securely, they can do it this way: Alice encrypts a message to Bob using Bob's public key. Only Bob can decrypt it and read it (using his private key). He can then send a return email to Alice using Alice's public key that only Alice can decrypt and read (using her own private key). If they wish, they can use this method to agree upon and exchange a shared symmetric key than can be used for further secure communications. Several automatic secure protocols use exactly this method or a variation of it. The alternate meaning is to make "secret key" synonymous with the "private key" of asymmetric encryption. In this case there is really no difference between secret key and public key encryption except for which key of the public/private key pair is being used and who can read it.
RSA's biggest advantage is that it uses Public Key encryption. This means that your text will be encrypted with someone's Public Key (which everyone knows about). However, only the person it is intended for can read it, by using their private key (which only they know about). Attempting to use the Public Key to decrypt the message would not work. RSA can also be used to "sign" a message, meaning that the recipient can verify that it was sent by the person they think it was sent by.
Public key encryption refers to a type of cypher or code architecture known as public key cryptography that utilizes two keys, or a key pair), to encrypt and decrypt data. One of the two keys is a public key, which anyone can use to encrypt a message for the owner of that key. The encrypted message is sent and the recipient uses his or her private key to decrypt it. This is the basis of public and private key encryption.
"party hard".
ONEAnswer Explanation: Only one key would be required for everyone to be able to encrypt and decrypt the message. Symmetric cryptography uses the same "shared secret" key for encrypting and decrypting a message. A message encrypted using a symmetric encryption algorithm can be decrypted by anyone with the key. For this reason it is very important to ensure that the key is protected from unauthorized use. One of the primary security issues surrounding the use of symmetric cryptography is the method used to transport the key to users who need it, as most forms of communication are susceptible to eavesdropping.