CS 472

Assignment #1

Due Midnight, Thursday Sept 29, 2011

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1. q1cipherfile.base64 is the result of encrypting a plain text q1plainfile using the xor encryption with a key embedded in image wahab.jpg. You are required to obtain q1plainfile.

2. q2plainfile1 is the known plain text of q2cipherfile1.base64 using xor encryption. Assuming the same key is used to produce another file q2cipherfile2.base64. You are required to obtain q2plainfile2.

3. q3cipherfile.base64 is the result of encrypting cs472 email list file (q3plainfile) using the xor encryption using a 1 character key from the set {a-z}. You are required to q3plainfile.

4. Submit your solutions to 1-3 as described below.

____________________________Submission Description______________________________

Use openssl it is installed at /usr/local/ssl/bin/openssl ) to:

1. Create a public/private key pair of your own, call the files containing your public and private keys: 

loginPublicKey.pem  & loginPrivateKey.pem where login is your login name. For example, for user wahab the files are called wahabPublicKey.pem  & wahabPrivateKey

2. Choose a password P, encrypt it using cs472PublicKey.pem and encode the result to base-64 and store it in a file called A1Password.base64

3. Let A1Solutions.tar be the tar file that contains all relevant files of your solution to  parts 1, 2 and 3 above.

For example, if you like to submit files: README f1 f2 .. fn use:  

% tar cf A1Solutions.tar README f1 f2 .. fn

Note that you MUST have one file called: README.

4. Use DES3 to encrypt A1Solutions.tar using your chosen P and let  A1Solutions.base64 be the  base64 encoding of the encrypted file.

5. Use SHA1 to sign the message digest of  A1Solutions.base64  using your private key. .

and let A1Signature.base64 be the  base64 encoding of the signature.

6. Use tar to create one file called   loginA1Submission.tar that contains:

1. loginPublicKey.pem

2. A1Password.base64

3. A1Solutions.base64

4. A1Signature.base64

For example, for student wahab:

% tar cf wahabA1Submission.tar wahabPublicKey.pem A1Password.base64 A1Solutions.base64 A1Signature.base64

7. Finally, submit loginA1Submission.tar to cs472 under the directory Assignment  #1.

Use the exact names listed above since a shell script is used to grade the assignment.