The Apache Milagro Cryptographic Library Note that the AMCL currently comes in two versions, version 2.2 and version 3.1 AMCL v2.2 is presented in what might be called a pre-library state. In the various supported languages the source code is made available, but it is not organised into rigid packages/crates/jars/whatever It is expected that the consumer will themselves take this final step, depending on the exact requirements of their project. Note that version 2.2 is no longer supported. AMCL v3.1 uses a standard Python 3 script to build libraries in all supported languages. New users should use this version. The main improvement is that AMCL v3 can optionally simultaneously support multiple elliptic curves and RSA key sizes within a single appliction. Note that AMCL is largely configure at compile time. In version 3 this configuration is handled by the Python script. AMCL is available in 32-bit and 64-bit versions in most languages. Limited support for 16-bit processors is provided by the C version. Now languages like to remain "standard" irrespective of the underlying hardware. However when it comes to optimal performance, it is impossible to remain architecture-agnostic. If a processor supports 64-bit instructions that operate on 64-bit registers, it will be a waste not to use them. Therefore the 64-bit language versions should always be used on 64-bit processors. Version 3.1 is a major "under the hood" upgrade. Field arithmetic is performed using ideas from http://eprint.iacr.org/2017/437 to ensure that critical calculations are performed in constant time. This strongly mitigates against side-channel attacks. Exception-free formulae are now used for Weierstrass elliptic curves. A new standardised script builds for the same set of curves across all languages.