Secure architectures for pairing based public key cryptography

Along with the growing demand for cryptosystems in systems ranging from large servers to mobile devices, suitable cryptogrophic protocols for use under certain constraints are becoming more and more important. Constraints such as calculation time, area, efficiency and security, must be considered by the designer. Elliptic curves, since their introduction to public key cryptography in 1985 have challenged established public key and signature generation schemes such as RSA, offering more security per bit. Amongst Elliptic curve based systems, pairing based cryptographies are thoroughly researched and can be used in many public key protocols such as identity based schemes. For hardware implementions of pairing based protocols, all components which calculate operations over Elliptic curves can be considered. Designers of the pairing algorithms must choose calculation blocks and arrange the basic operations carefully so that the implementation can meet the constraints of time and hardware resource area. This thesis deals with different hardware architectures to accelerate the pairing based cryptosystems in the field of characteristic two. Using different top-level architectures the hardware efficiency of operations that run at different times is first considered in this thesis. Security is another important aspect of pairing based cryptography to be considered in practically Side Channel Analysis (SCA) attacks. The naively implemented hardware accelerators for pairing based cryptographies can be vulnerable when taking the physical analysis attacks into consideration. This thesis considered the weaknesses in pairing based public key cryptography and addresses the particular calculations in the systems that are insecure. In this case, countermeasures should be applied to protect the weak link of the implementation to improve and perfect the pairing based algorithms. Some important rules that the designers must obey to improve the security of the cryptosystems are proposed. According to these rules, three countermeasures that protect the pairing based cryptosystems against SCA attacks are applied. The implementations of the countermeasures are presented and their performances are investigated.

Suicide and deliberate self harm in older Irish adults

Background: Hospital-treated deliberate self harm and suicide among older adults have rarely been examined at a national level. Methods: The Irish Central Statistics Office provided suicide and undetermined death data for 1980-2006. The National Registry of Deliberate Self Harm collected data relating to deliberate self harm presentations made in 2006-2008 to all 40 Irish hospital emergency departments. Results: Rates of female suicide among older adults (over 55 years) were relatively stable in Ireland during 1980-2006 whereas male rates increased in the 1980s and decreased in more recent decades. Respectively, the annual male and female suicide and undetermined death rate was 22.1 and 7.6 per 100,000 in 1997-2006. Male and female deliberate self harm was 3.0 and 11.0 times higher at 67.4 and 83.4 per 100,000, respectively. Deliberate self harm and suicide decreased in incidence with increasing age. Deliberate self harm generally involved drug overdose (male: 72%; female 85%) or self-cutting (male: 15%; female 9%). The most common methods of suicide were hanging (41%) and drowning (29%) for men and drowning (39%) and drug overdose (24%) for women. City and urban district populations had the highest rates of hospital-treated self harm. The highest suicide rates were in urban districts. Conclusions: Older Irish adults have high rates of hospital-treated deliberate self harm but below average rates of suicide. Drowning was relatively common as a method of suicide. Restricting availability of specific medications may reduce both forms of suicidal behavior.