Implementing a commitment scheme in java

Question

Are there any implementations of cryptographic commitment schemes available as API/libraries in Java? I looked around in the security package and couldn't find much. Any help is appreciated.

Thanks

Answer 1

There is a huge variety of commitment schemes out there; they have various characteristics. The simplest commitment scheme is a simple hash, and Java does offer implementation of the most standard hash functions (through the java.security.MessageDigest API). More advanced commitment schemes allow for proving that the commitment is "correct" (the committed data fulfills some algebraic property) without opening it. Many such schemes have been designed, but none is a standard in its own right, so there is no readily available implementation in standard Java.

(That's the difference between a cryptographic algorithm, as described in an academic article, and a standard: the latter states unambiguously where each bit goes, dealing with boring but important issues like endianness and corner cases.)

At least Java does offer some useful tools for implementing cryptographic algorithms, namely BigInteger and hash functions.