Secured Mobile Messaging

Abstract:

SMS messages are one of the popular ways of communication. Sending an SMS 

is cheap, fast and simple. When confidential information is exchanged using 

SMS, it is very difficult to protect the information from SMS security threats 

like man-in-middle attack, DOS attack as well as ensure that the message is 

sent by authorized senders. These papers describe solution that provides SMS 

security that guarantees provision of confidentiality, authentication, and 

integrity service. These provide hybrid compression encryption technique to 

secure the SMS data. The proposed techniques encrypt the SMS Elliptic curve 

encryption techniques and compress the encrypted SMS to reduce its length 

this document using lossless compression techniques.

One SMS message can contain at most 140 bytes (1120 bits) of data, so one 

SMS message can contain up to:

• 160 characters if 7-bit character encoding is used. (7- bit character encoding 

is suitable for encoding Latin characters like English alphabets.)

• 70 characters if 16-bit Unicode UCS2 (2-byte Universal Character Set) 

character encoding is used. (SMS text messages containing non-Latin 

characters like Chinese characters should use 16-bit character encoding.)

SMS text messaging supports languages internationally. It works fine with all 

languages supported by Unicode, including Arabic, Chinese, Japanese and 

Korean.

SMS Security: What is Needed?

• Authentication: Confirm true identities between sender and receiver, and 

prevent impersonation attack from illegal intruders.

• Confidentiality: Ensure that decrypted messages are accessible only to 

those authorized senders and receivers.

• Integrity: Ensure that receivers can check out whether the message has 

been modified, and prevent tampered messages.

Comparisons performance:

Following are some measurements used to evaluate the performances of 

lossless algorithms.

Compression Ratio is the ratio between the size of the compressed file and 

the size of the source file.

Compression Ratio=size after compression/size before compression

Compression Factor is the inverse of the compression ratio. That is the ratio 

between the size of the source file and the size of the compressed file.

Compression factor=size before compression/size after compression

Saving Percentage calculates the shrinkage of the source file as a percentage.

Saving Percentage=size before compression-size after compression/ size 

before compression.

All the above methods evaluate the effectiveness of compression algorithms 

using file sizes.

CONCLUSION:

In this report we studied the techniques for securing SMS. The proposed 

technique combines the encryption and compression process. The proposed 

technique encrypts the SMS using Elliptic Curve algorithm. After this step the 

encrypted SMS compressed using a lossless algorithm i.e. Shannon Fano 

algorithm. The advantage of this technique is achieving the protection criteria 

such as confidentiality and authenticity between two communication parties 

and at the same time decreasing the message lengths.