Addressing various TODOs and minor cleanups (#127)

Cargo.lock

@@ -389,12 +389,6 @@ version = "1.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bb1f6b1ce1c140482ea30ddd3335fc0024ac7ee112895426e0a629a6c20adfe3"
 
-[[package]]
-name = "fiat-crypto"
-version = "0.1.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0f6ab97095615857b6ad00a8330fff0e443f1def9fd357cef82d0ca0677b616b"
-
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -613,7 +607,6 @@ dependencies = [
  "curve25519-dalek",
  "digest",
  "displaydoc",
- "fiat-crypto",
  "generic-array",
  "generic-bytes",
  "generic-bytes-derive",
@@ -630,7 +623,6 @@ dependencies = [
  "sha2",
  "subtle",
  "thiserror",
- "x25519-dalek",
  "zeroize",
 ]
 
@@ -1023,18 +1015,6 @@ dependencies = [
  "unicode-xid",
 ]
 
-[[package]]
-name = "synstructure"
-version = "0.12.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b834f2d66f734cb897113e34aaff2f1ab4719ca946f9a7358dba8f8064148701"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
- "unicode-xid",
-]
-
 [[package]]
 name = "tempfile"
 version = "3.1.0"
@@ -1255,34 +1235,8 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 
-[[package]]
-name = "x25519-dalek"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bc614d95359fd7afc321b66d2107ede58b246b844cf5d8a0adcca413e439f088"
-dependencies = [
- "curve25519-dalek",
- "rand_core",
- "zeroize",
-]
-
 [[package]]
 name = "zeroize"
 version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "05f33972566adbd2d3588b0491eb94b98b43695c4ef897903470ede4f3f5a28a"
-dependencies = [
- "zeroize_derive",
-]
-
-[[package]]
-name = "zeroize_derive"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "de251eec69fc7c1bc3923403d18ececb929380e016afe103da75f396704f8ca2"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
- "synstructure",
-]