crypto_box: Revert "select x25519-dalek backend automatically (#55)" (#63)

This reverts commit a994fbf

Automatic selection is not working correctly. See comments here:

#55

Author: tarcieri

.github/workflows/crypto_box.yml

@@ -36,8 +36,8 @@ jobs:
           toolchain: ${{ matrix.rust }}
           target: ${{ matrix.target }}
           override: true
-      - run: cargo build --target ${{ matrix.target }} --release --no-default-features
-      - run: cargo build --target ${{ matrix.target }} --release --no-default-features --features heapless
+      - run: cargo build --target ${{ matrix.target }} --release --no-default-features --features u32_backend
+      - run: cargo build --target ${{ matrix.target }} --release --no-default-features --features u32_backend,heapless
 
   test:
     runs-on: ubuntu-latest
@@ -53,9 +53,9 @@ jobs:
           profile: minimal
           toolchain: ${{ matrix.rust }}
           override: true
-      - run: cargo test --release --no-default-features
-      - run: cargo test --release
-      - run: cargo test --release --all-features
+      - run: cargo test --release --features std
+      - run: cargo test --release --features std,heapless
+      - run: cargo test --release --features std,serde
 
   cross:
     strategy:
@@ -78,4 +78,4 @@ jobs:
           target: ${{ matrix.target }}
           override: true
       - run: cargo install cross
-      - run: cross test --release --target ${{ matrix.target }} --all-features
+      - run: cross test --release --target ${{ matrix.target }} --features std,serde

crypto_box/Cargo.toml

@@ -22,32 +22,29 @@ aead = { version = "0.5.1", default-features = false }
 chacha20 = "0.9"
 chacha20poly1305 = { version = "0.10.1", default-features = false, features = ["rand_core"] }
 salsa20 = "0.10"
+x25519-dalek = { version = "1", default-features = false }
 xsalsa20poly1305 = { version = "0.9", default-features = false, features = ["rand_core"] }
 zeroize = { version = "1", default-features = false }
 
 # optional dependencies
 serdect = { version = "0.1", optional = true, default-features = false }
 
-[target.'cfg(target_pointer_width = "32")'.dependencies]
-x25519-dalek = { version = "1", default-features = false, features = ["u32_backend"] }
-
-[target.'cfg(target_pointer_width = "64")'.dependencies]
-x25519-dalek = { version = "1", default-features = false, features = ["u64_backend"] }
-
 [dev-dependencies]
 bincode = "1"
 rand = "0.8"
 rmp-serde = "1"
 
 [features]
-default = ["alloc", "getrandom"]
+default = ["alloc", "getrandom", "u64_backend"]
 std = ["aead/std"]
+serde = ["serdect"]
 alloc = ["aead/alloc"]
 getrandom = ["aead/getrandom", "rand_core"]
 heapless = ["aead/heapless"]
 rand_core = ["aead/rand_core"]
-serde = ["serdect"]
+u32_backend = ["x25519-dalek/u32_backend"]
+u64_backend = ["x25519-dalek/u64_backend"]
 
 [package.metadata.docs.rs]
-all-features = true
+features = ["serde"]
 rustdoc-args = ["--cfg", "docsrs"]

crypto_box/src/lib.rs

@@ -164,9 +164,6 @@
 //! [ECIES]: https://en.wikipedia.org/wiki/Integrated_Encryption_Scheme
 //! [`heapless::Vec`]: https://docs.rs/heapless/latest/heapless/struct.Vec.html
 
-#[cfg(not(any(target_pointer_width = "32", target_pointer_width = "64")))]
-compile_error!("`crypto-box` requires either a 32-bit or 64-bit target");
-
 pub use aead::{self, rand_core};
 pub use xsalsa20poly1305::Nonce;