[hsmtool] Support SPHINCS+ in CloudKMS

1. Use the CloudKMS REST/json API to perform SPHINCS+ signing.

Signed-off-by: Chris Frantz <[email protected]>
(cherry picked from commit 2ce2a91)

Author: cfrantz

sw/host/hsmtool/BUILD

@@ -126,11 +126,12 @@ rust_library(
         "src/commands/spx/verify.rs",
         "src/commands/token.rs",
         "src/error.rs",
+        "src/extra/mod.rs",
+        "src/extra/spxef.rs",
+        "src/extra/spxkms.rs",
         "src/lib.rs",
         "src/module.rs",
         "src/profile.rs",
-        "src/extra/mod.rs",
-        "src/extra/spxef.rs",
         "src/util/attribute/attr.rs",
         "src/util/attribute/data.rs",
         "src/util/attribute/date.rs",
@@ -164,6 +165,7 @@ rust_library(
         "//sw/host/hsmtool/acorn",
         "//sw/host/sphincsplus",
         "@crate_index//:anyhow",
+        "@crate_index//:base64ct",
         "@crate_index//:clap",
         "@crate_index//:cryptoki",
         "@crate_index//:cryptoki-sys",
@@ -178,6 +180,7 @@ rust_library(
         "@crate_index//:pem-rfc7468",
         "@crate_index//:rand",
         "@crate_index//:regex",
+        "@crate_index//:reqwest",
         "@crate_index//:rsa",
         "@crate_index//:rustix",
         "@crate_index//:serde",

sw/host/hsmtool/src/extra/mod.rs

@@ -3,5 +3,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 mod spxef;
+mod spxkms;
 
 pub use spxef::SpxEf;
+pub use spxkms::SpxKms;