1, If a cryptanalyst thinks that a user has used the same key to encrypt two different files, he can XOR the two files together and cancel out the output from the PRNG.

2, An analytical attack in which a cryptanalyst can submit an unlimited number of plaintext messages and examine the corresponding ciphertext.

3, This leaves the cryptanalyst with a file that contains only the two original files XORed against each other.

4, Maxim No. 2: Only a cryptanalyst, if anybody, can judge the security of a cryptosystem.

5, In these attacks, if the cryptanalyst knows the file type, then he can use knowledge of header formats to guess at the key stream used to encode the file.

6, Only a cryptanalyst , if anybody, can judge the security of a cryptosystem.

7, An analytical attack in which a cryptanalyst possesses a substantial quantity of corresponding plaintext and ciphertext.

8, If the data to be protected is already encrypted, then authenticity requires that a cryptanalyst would not be able to substitute a false ciphertext without detection.

9, You're new in the field; no one's heard of you, and you don't have any credentials as a cryptanalyst .