15 examples of some common Cryptographic Attacks

1. Brute force. Trying every possible combination of key patterns; the longer the key length, the more difficult it is to find the key with this method.

2. Known plaintext. The attacker has a copy of the plaintext corresponding to the ciphertext.

3. Chosen plaintext. Chosen plaintext is encrypted and the output ciphertext is obtained.

4. Adaptive chosen plaintext. A form of a chosen plaintext attack where the selection of the plaintext is altered according to the previous results.

5. Ciphertext only. Only the ciphertext is available.

6. Chosen ciphertext. Portions of the ciphertext are selected for trial decryption while having access to the corresponding decrypted plaintext.

7. Adaptive chosen ciphertext. A form of a chosen ciphertext attack where the selection of the portions of ciphertext for the attempted decryption is based on the results of previous attempts.

8. Birthday attack. Usually applied to the probability of two different messages using the same hash function, which produces a common message digest; or given a message and its corresponding message digest, finding another message that when passed through the same hash function generates the same specific message digest. The term birthday comes from the fact that in a room with 23 people, the probability of two or more people having the same birthday is greater than 50 percent.

9. Meet-in-the-middle. Is applied to double encryption schemes by encrypting known plaintext from one end with each possible key (K) and comparing the results ¡°in the middle¡± with the decryption of the corresponding ciphertext with each possible K.

10. Man-in-the-middle. An attacker taking advantage of the store-and-forward nature of most networks by intercepting messages and forwarding modified versions of the original message while between two parties attempting secure communications.

11 Differential cryptanalysis. Is applied to private key cryptographic systems by looking at ciphertext pairs, which were generated through the encryption of plaintext pairs, with specific differences and analyzing the effect of these differences.

12. Linear cryptanalysis. Using pairs of known plaintext and corresponding ciphertext to generate a linear approximation of a portion of the key.

13. Differential linear cryptanalysis. Using both differential and linear approaches.

14. Factoring. Using a mathematical approach to determine the prime factors of large numbers.

15. Statistical. Exploiting the lack of randomness in key generation.