Cargo Features

ecb = { version = "0.1.2", default-features = false, features = ["std", "alloc", "block-padding"] }
default = block-padding

The block-padding feature is set by default whenever ecb is added without default-features = false somewhere in the dependency tree.

std = alloc

Enables std of cipher

alloc std?

Enables alloc of cipher

block-padding default

Enables block-padding of cipher

ECB has 4 features without comments.