Diffie Hellman and RSA are both asymmetric key algorithms, also known as public-key cryptography system which uses two keys to encrypt a plain text.
Diffie Hellman(DH) |
RSA |
| DH stands for Diffie Hellman | RSA stands for Rivest, Shamir, Adleman. |
| First published in 1976 | First published in 1977 |
| Diffie Hellman was designed by Whitfield Diffie and Martin Hellman | RSA was designed by Ron RIvest, Adi Shamir, and Leonard Adleman |
| Allows two parties to establish a connection over an insecure communication channel, a shared secret key that only the two parties know. | In RSA, the sender encrypts the data using the public key and the receiver decrypts the data using his private key. |
| Generating ephemeral keys for Diffie Hellman is extremely easy | Generating ephemeral keys for RSA is extremely difficult |
| Encryption is expensive | Encryption is cheaper |
| Diffie Hellman 1024 bits is more robust than RSA | RSA 1024 bits is less robust than Diffie Hellman |
| Public-key is bigger to encode | Public-key is smaller to encode |
| Diffie Hellman is less secure than RSA | RSA is more secure than Diffie Hellman |
Also read: Difference between AES and DES in cryptography
Advantages and Disadvantages of Diffie Hellman
Advantages of Diffie Hellman
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Sharing of secret-key is safe.
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Sender and receiver don’t need any prior knowledge of each other.
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Once the keys are exchanged the communication of data can be done through an insecure channel.
Disadvantages of Diffie Hellman
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The algorithm cannot be used for signing digital signatures.
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The Diffie Hellman key exchange is susceptible to man-in-the-middle attack.
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Only used for symmetric key exchange.
Advantages and Disadvantages of RSA
Advantages of RSA
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Easier to implement and understand.
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RSA is stronger than other symmetric key algorithms.
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RSA has overcome the weakness of symmetric algorithms i.e. authenticity and confidentiality.
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Very fast and simple encryption and verification.
Disadvantages of RSA
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RSA has too much computation.
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It requires a more computer power supply compared to single-key encryption.
Protocols that use Diffie-Hellman to enhance security
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Transport Layer Security (TLS) / Secure Socket Layers (SSL)
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Internet Protocol Security (IPSec)
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Secure Shell (SSH)
What kind of attack is a standard Diffie-Hellman key exchange vulnerable to?
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Man-in-the-middle attack
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