Cargo Features
solana-secp256k1 has no features set by default.
[dependencies]
solana-secp256k1 = { version = "0.1.3", features = ["big-mod-exp"] }- big-mod-exp = solana-nostd-big-mod-exp
Features from optional dependencies
In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.