Many cryptography arithmetic operations employ the method of modular multiplication. The underlying binary adders in modular multipliers is targeted in this development. The carry-save adder, carry-lookahead adder and carry-skip adder have been studied and compared. They showed interesting features and trade-offs.improved crypto designs are promised by the beneficial details that the design shows.

MODULAR MULTIPLICATION
Modular multiplication is defined as the computation of P=A×B mod M, which are represented using n bits. various algorithms for modular multiplication has been proposed and their hardware implementation has been done by many. Doing the multiplication first and then dividing the result by the modulus is the straightforward method. But the time and area requirements prove this method to be too costly.

BINARY ADDERS
It is one of the most important operations in modular multiplication and is mostly used operation in computers. In RISC machines nearly 70% of the
instructions perform additions .
The different types of adders in literature are:
-Ripple-Carry Adder (RCA)
-Carry-Save Adder (CSA)
- Carry-Lookahead Adder (CLA)
-Carry-Skip Adder (CSK)

COMPARISON
The the carry-skip adder and carry-lookahead adder are the fastest in the class and thes are compared here.

see the report for more details:
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Code for Low cost high performance VLSI architecture for Montgomery multiplication