Credit Card Checksum

Did you know that credit card numbers are not just arbitrary numbers? They satisfy a simple mathematical formula for verification. Use this tool to verify any credit card number.

Random Generator

Random numbers are often used in cryptography. This tool can generate numbers of arbitrary size for you. It can even be used for coin tossing if you set the range to: 0 <= number < 2.

Hash

Hash functions compress long strings to a small message digest or digital fingerprint. They are used for authentication and message integrity. Software often comes with a message digest that allows you to verify the integrity of a download. This tool offers you a few frequently used checksum and hash functions, including SHA-1, MD5 and RipeMD.

Primer

Prime numbers are numbers that have no other dividers than 1 and itself. They are used in the RSA cryptographic algorithm. How would you know if: 156741647827472757276840657891 is a prime? Test it in this tool, or generate your own arbitrary size prime!

Calcu Larger

Some cryptographic algorithms use big number calculations. Want to check the public key signature or certificate yourself? Use this calculator to perform a variety of big number operations!

DES

The Data Encryption Standard is the classical algorithm used for symmetrical encryption. Despite of its old age (almost 30 years!) it is still used in many implementations, including most financial smart cards. The original key size of 56 bits is no longer secure, therefore the algorithm is nowadays mostly applied in Triple-DES mode. Use this tool to generate your own DES signatures.

AES

The Advanced Encryption Standard was developed a couple of years ago to replace the DES. It is far more secure and due to its small footprint very suitable for smart cards. The AES will be the core algorithm for authentication in the 3rd generation mobile networks (UMTS). Use this tool to generate your own AES signatures.

COMP128 v1

COMP128 has been the most popular GSM authentication algorithm. Use this tool to generate your own COMP128 signature.

These tools require a Java Runtime Environment: