Next: 3.1.5 Is cryptography patentable Up: 3.1 General Previous: 3.1.3 What is public-keyThe primary advantage of public-key cryptography is increased security:the private keys do not ever need to be transmitted or revealed toanyone. In a secret-key system, by contrast, there is always a chancethat an enemy could discover the secret key while it is beingtransmitted.
Another major advantage of public-key systems is that they can providea method for digital signatures. Authentication via secret-key systemsrequires the sharing of some secret and sometimes requires trust of athird party as well. A sender can then repudiate a previously signedmessage by claiming that the shared secret was somehow compromised byone of the parties sharing the secret. For example, the Kerberossecret-key authentication system involves a central database that keepscopies of the secret keys of all users; a Kerberos-authenticatedmessage would most likely not be held legally binding, since an attackon the database would allow widespread forgery. Public-keyauthentication, on the other hand, prevents this type of repudiation;each user has sole responsibility for protecting his or her privatekey. This property of public-key authentication is often callednon-repudiation.
Furthermore, digitally signed messages can be proved authentic to athird party, such as a judge, thus allowing such messages to be legallybinding. Secret-key authentication systems such as Kerberos weredesigned to authenticate access to network resources, rather than toauthenticate documents, a task which is better achieved via digitalsignatures.
A disadvantage of using public-key cryptography for encryption isspeed: there are popular secret-key encryption methods which aresignificantly faster than any currently available public-key encryptionmethod. But public-key cryptography can share the burden withsecret-key cryptography to get the best of both worlds.
For encryption, the best solution is to combine public- and secret-keysystems in order to get both the security advantages of public-key systemsand the speed advantages of secret-key systems. The public-key system canbe used to encrypt a secret key which is then used to encrypt the bulk of afile or message. This is explained in more detail in Question3.2.12 in the case of RSA. Public-key cryptography is not meantto replace secret-key cryptography, but rather to supplement it, to make itmore secure. The first use of public-key techniques was for secure keyexchange in an otherwise secret-key system; this is still one of itsprimary functions.
Secret-key cryptography remains extremely important and is the subjectof much ongoing study and research. Some secret-key encryption systemsare discussed in Questions 3.5.1 and 3.5.5.
Next: 3.1.5 Is cryptography patentable Up: 3.1 General Previous: 3.1.3 What is public-keyDenis Arnaud
12/19/1997FAQs
Public key cryptology has an advantage over symmetric private key encryption systems because it circumvents the logistics and risks inherent to secretly swapping keys.
What is the difference between secret key cryptography and public-key cryptography? ›
Public key encryption is the process where a pair of public and private keys is used to encode and decode data. Private key encryption is a process that uses a single key, also known as a secret key, to encode and decode data.
What are the advantages of secret key cryptography? ›
You use one key to encrypt the information and the same key to decrypt the information. The benefits is that it is very fast but since both parties use the same key, there needs to be a secure channel for key exchange. In symmetric encryption, the secret key needs to be protected and controlled.
What are the cons of secret key cryptography? ›
One of the major problems with secret-key cryptography is the logistical issue of how to get the key from one party to the other without allowing access to an attacker.
What are the weaknesses of public key cryptography? ›
As with all security-related systems, there are various potential weaknesses in public-key cryptography. Aside from poor choice of an asymmetric key algorithm (there are few that are widely regarded as satisfactory) or too short a key length, the chief security risk is that the private key of a pair becomes known.
What are the benefits of public-key cryptography? ›
Advantages. Public key cryptography strengthens authentication by enabling the verification of message authenticity through digital signatures. This ensures that recipients can confidently validate the origin of messages, enhancing the overall security of communication channels.
What is the difference between a public key and a private key? ›
To conclude, private keys can be used for both encryption and decryption, while Public keys are used only for the purpose of encrypting the sensitive data. Private keys are shared between the sender and the receiver, whereas public keys can be freely circulated among multiple users.
What are the main advantages and disadvantages of symmetric key cryptography? ›
The benefit of symmetric key encryption is that it is fast and convenient to set up. Plus, this method is simple and easy to understand, so everyone can easily master it. The single disadvantage: the receiver must get the secret key from the sender.
What is the main difference between conventional and public key encryption? ›
The Public key encryption technique is also known as asymmetric cryptography. It uses a pair of keys to secure data communication whereas, in a private key, both sides, i.e., the sender and receiver, use the same key (or secret key) for Encryption/Decryption.
What is the difference between public-key cryptography and encryption? ›
Public key cryptography is a method of encrypting or signing data with two different keys and making one of the keys, the public key, available for anyone to use. The other key is known as the private key. Data encrypted with the public key can only be decrypted with the private key.
A cryptographic system that uses two keys -- a public key known to everyone and a private or secret key known only to the recipient of the message.
What are the advantages & disadvantages of public key encryption? ›
In asymmetric or public key, cryptography there is no need for exchanging keys, thus eliminating the key distribution problem. The primary advantage of public-key cryptography is increased security: the private keys do not ever need to be transmitted or revealed to anyone.
What is the difference between key and secret in encryption? ›
A secret is anything that you want to tightly control access to, such as API keys, passwords, or certificates. A key is a cryptographic key represented as a JSON Web Key [JWK] object. Key Vault supports RSA and Elliptic Curve Keys only.
Is secret key cryptography effective? ›
Introduction. Secret key cryptography is effective for communication over insecure channels as the piece of information or parameter used helps the information to encrypt and decrypt messages. There are two different keys used for asymmetric encryption in which one is a public key, the other is a secret key.
What are the disadvantages of public key authentication? ›
Disadvantages. If an attacker gains access to your private key, there is a significant security risk as they can decrypt and read all your messages. The confidentiality of your communication becomes compromised, emphasizing the importance of safeguarding private keys.
What is the difference between private key and public key cryptography? ›
To conclude, private keys can be used for both encryption and decryption, while Public keys are used only for the purpose of encrypting the sensitive data. Private keys are shared between the sender and the receiver, whereas public keys can be freely circulated among multiple users.
What are the advantages of public and private keys? ›
Benefits of Public-Private Key Encryption
By using a public and private key for encryption and decryption, recipients can be confident that the data is what the sender says it is and the sender is who they say they are. The recipient is assured of the confidentiality, integrity, and authenticity of data exchange.
