Lab 7 - SECURITY IN APPLICATIONS

Email has two part, header and body. Header part used to state the sender and email recipient. Body part is content of the message or email.

Security in email:

· Confidentiality

· Data origin authentication

· Message integrity

· Non-repudiation of origin

· Key management

MIME

Secure MIME is the new (proposed) Internet standard for secure email exchange, developed by RSA. It is not yet an official standard, but several vendors (including Netscape) already support S/MIME. It is probably the best long term solution, since it is an open Internet standard.

Typically is not necessary to make any modifications for S/MIME on the server. For instance with MS Exchange, it integrates into the exchange client via the MAPI interface.


Advantages:

1. It functions with both Eudora Pro 3.0 and Exchange (and can use the same certificates on the same machine).
2. No changes are required to the exchange server.
3. Certificates may either be self signed, or signed by a TTP such as

Disadvantages:

1. The user interface is not perfect, e.g. a user could easily unintentionally send an unencrypted email. The icons used to represent email don't seem to indicate if the received email was successfully decrypted and the signature checked. It is possible that these problems can be overcome by adding additional buttons to the toolbar, though this increases support costs.

2. When a signed message is received from someone for whom no certificate currently exists, the certificate is automatically added to the certificate database. Before this certificate can be used, it must be manually trusted. This procedure is a bit confusing for normal users, it should be handled by a nice pop-up box when the signed email is received.


PGP

PGP is a freeware and commercial email and file encryption utility. It is also discussed in the chapter "Security Mechanisms".
Secure Shell is a program to log into another computer over a network, to execute commands in a remote machine, and to move files from one machine to another. It provides strong authentication and secure communications over insecure channels. It is a replacement for rlogin, rsh, rcp, and rdist.

SSH

SSH protects a network from attacks such as IP spoofing, IP source routing, and DNS spoofing. An attacker who has managed to take over a network can only force ssh to disconnect. He or she cannot play back the traffic or hijack the connection when encryption is enabled.

When using ssh's slogin (instead of rlogin) the entire login session, including transmission of password, is encrypted; therefore it is almost impossible for an outsider to collect passwords.

Biometric

How Does Biometric Encryption Work?

Encryption is a mathematical process that helps to disguise the information contained in messages that is either transmitted or stored in a database, and there are three main factors that determine the security of any crypto system; the complexity of the mathematical process or algorithm, the length of the encryption key used to disguise the message, and safe storage of the key, known as key management.

The complexity of the algorithm is important because it directly correlates to how easy the process is to reverse engineer. One would think that this is the area of encryption that is the easiest to break, however most crypto systems are extremely well constructed and these are the least of the three factors that are vulnerable to attack.

The length of the encryption key used to disguise the message is the next important piece of the encryption process. The shorter the encryption key length, the more vulnerable the data is to a "brute force" attack. This term refers to an individual trying to improperly access data by trying all combinations of possible passwords that would allow access to the account. In non-biometric encryption processes such as passwords or PIN numbers, depending on the length of the key, the information may be vulnerable to access by unauthorized users. For example, a key that is three characters long would be much more prone to attack than one that is ten characters long because the number of possible permutations that must be run to find the right key are much higher in the key that contains ten characters. With current computer power, it is estimated that it would take four hundred years to find the right access combination for a sixty-four character key. Biometric encryption makes standard character encryption obsolete by replacing or supplementing the normal key characters with a personal identifier of the user that there can only be one perfect match for. Without this biometric key the information is inaccessible.

Safe storage of the key is the most vulnerable area in the encryption process. What would seem to be the easiest to manage becomes the most difficult because passwords or PINs can be lost or stolen. Good encryption keys are much too long for normal individuals to remember easily so they are usually stored on paper, smart cards, or diskette which makes them accessible to non-authorized users. Biometric encryption systems allow the user to transport the access key around without the need to make it vulnerable to be lost or stolen.

There are two broad categories of encryption systems; single key (symmetric) sytems and two key (public) systems. Symmetric systems utilize a single key for both the sender and receiver for the purpose of coding and decoding data. In 1972, IBM developed DES (Data Encryption Standard) which was adopted worldwide by 1977 as the most common single key system in the banking and financial sectors. The process of transmitting this type of key over such networks as the Internet is one of the major failures due to the vunerability of a single key system to interception. Electronic commerce requires that transactions be conducted over open networks instead of dedicated networks and single key systems do not offer a high enough level of security for such transmissions. This issue of security is why public key systems have been developed. Two-key systems use a public key to encrypt the data and a private key to decrypt the data. The public key systems allows better encryption than single key systems, however certification of the recipient of messages becomes an issue, which causes a hierarchy of certification to be developed resulting in a much slower processing time. Biometrics can aid in this process due to the inherent nature of using a physical trait of the desired recipient to decipher the message. It is this issue that has caused biometric encryption techniques to be valued for electronic commerce.