E-Commerce Security Coursework March 2004 Jonathan Lelliott - A052956 Part II - 1 The RSA Algorithm is a form of asymmetric public key cryptography that bases its security in the difficulty of factoring numbers. For Eve to properly decrypt the message that she intercepted, she would normally require the private key of the intended recipient. The sender issues a public key to each intended recipient of the message who then use import it into their 'key ring'. …showed first 75 words of 1743 total…

…showed last 75 words of 1743 total…repetitive part-blocks of cipher text can emerge, laying the groundwork for a codebook attack where the plaintext patterns are fairly obvious. Security can be improved however if random pad bits are added to each block. On the other hand, 64-bit or larger blocks should contain enough unique characteristics to make a codebook attack unlikely to succeed. In this case, being as the message going to be very short, this weakness should not be easily exploited.