CypherCalc is a full-featured, programmable calculator designed for multi precision integer arithmetic. You can use CypherCalc to perform "big number" math operations such as exponentiation, modular multiplication, and Montgomery products. 

CypherCalc is a great time-saver for those who work in the fields of Cryptography and Cryptanalysis. It is intended for use in the design, testing, and analysis of cryptographic algorithms involving key exchanges, modular exponentiation, modular inverses, and Montgomery Math. 

CypherCalc has built-in GCD and SHA 1 tools, and a CRC tool that can generate CRC tables for your applications. It can also assist in the design of math routines for crypto algorithms and methods such as RSA, Diffie-Hellman, Elliptic Curves, and Block Ciphers like DES and 3DES, including operational modes such as ECB (Electronic Code Book), CBC (Cipher Block Chain), CFB (Cipher Feed Back), and OFB (Output Feed Back).  

CypherCalc saves countless hours of program development time by providing a reliable source of known answers. You can check your algorithms against CypherCalc's results in seconds. Also included is a simple scripting program language that allows you to automate repetitive calculations and algorithms. 

The example at right shows a 320-bit modular exponentiation. The expression being evaluated is entered into the "Expression" box. In this example, the operands were previously stored in CypherCalc's memory A, B, and N, where A is a 320-bit base, B is a 160-bit exponent, and N is a 320-bit modulus. When the "Compute" button is clicked, the operands are recalled from memory, A^B % N is computed, and the 320-bit result is displayed in the "Result" window. 

• The Hex/Decimal Converters convert the radix of large numbers in CypherCalc's "Result" box. You can convert CypherCalc's results, or paste large numbers in from other applications to be converted by CypherCalc.
• The One's Complement tool inverts the current contents of CypherCalc's "Result" box.
• The Format Numbers tool can be used to strip or add prefixes, delimiters, etc from numbers. It can also exchange the words of a number, from most-significant to least-significant. This is handy when cutting and pasting large numbers to/from other applications that may require a different format.
• The Pseudorandom Generator provides a source of numbers to test your application.
• The Randomization Check tool provides statistical information about numbers, to help assess their cryptographic randomness.
• The Greatest Common Divisor tool solves the Extended Euclidean Algorithm.
• The Montgomery Image tool computes Montgomery Images of your numbers, with respect to a given modulus.
• The Montgomery Product tool computes Montgomery Products.
• The Find R^2 mod n tool provides a quick way to compute Montgomery's R² mod n.
• The Find n0' tool provides a quick way to compute Montgomery's n0' parameter.
• The Find Barrett mu tool provides a quick way to compute the Barrett reduction parameter mu.
• The Modular Inverse tool provides a quick way to compute modular inverses.
• The Bit Shifter is a user-configurable shift register for designing custom CRC's, FEC's, PSRs, etc.
• The CRC Tool can be used to test and evaluate a variety of CRC algorithms, and produce CRC lookup tables for use in your applications.
• The SHA-1 Tool can be used to compute the message digest of your input data.