This is a meta-issue related to multiple possible improvements :
- (1) moving all crypto dependency at the same place
- (2) ability to run a test suite that is directly related to parity use
- (3) ability to run bench on different crates
- (4) traits over main parity crypto use, and hability to switch crates without to much efforts (not meant to be std crypto trait, more a convenient way to audit/check our crypto libs usage).
- (5) wasm32 compatibility/alternative
- (6) no_std compatibility/alternative

Following steps are proposed :

• rust-crypto dependency removal #85 Remove rust-crypto. The rust-crypto crate is unmaintained and in itself is problematics for (5) and (6). Probably going for RustCrypto.
• Add support for secp256k1 with traits. Concur to (1) and (4)
• Enable cross-compilation to wasm32 target. Concur to (5)
• Make the crate no_std compatible. Concur to (6)
• Add further trait and tests/bench...

A previous PR covered first three steps is at #80 , I put it on ice in favor of smaller PRs. It contains lots of additional information.