diff --git a/sdk/aws-sigv4/Cargo.toml b/sdk/aws-sigv4/Cargo.toml
index 5bdb2a491d42..10b1adfab4f3 100644
--- a/sdk/aws-sigv4/Cargo.toml
+++ b/sdk/aws-sigv4/Cargo.toml
@@ -1,4 +1,8 @@
 # Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
+[[bench]]
+name = "hmac"
+harness = false
+
 [package]
 name = "aws-sigv4"
 version = "0.51.0"
@@ -22,9 +26,10 @@ default = ["sign-http"]
 hex = "0.4"
 once_cell = "1.8"
 regex = "1.5"
-ring = "0.16"
 time = "0.3.5"
 tracing = "0.1"
+hmac = "0.12"
+sha2 = "0.10"
 
 [dependencies.aws-smithy-eventstream]
 path = "../aws-smithy-eventstream"
@@ -52,6 +57,7 @@ version = "2.1"
 optional = true
 
 [dev-dependencies]
+criterion = "0.4"
 bytes = "1"
 httparse = "1.5"
 pretty_assertions = "1.0"
@@ -60,3 +66,5 @@ proptest = "1"
 [dev-dependencies.time]
 version = "0.3.4"
 features = ["parsing"]
+[target."cfg(not(any(target_arch = \"powerpc\", target_arch = \"powerpc64\")))".dev-dependencies]
+ring = "0.16"
diff --git a/sdk/aws-sigv4/benches/hmac.rs b/sdk/aws-sigv4/benches/hmac.rs
new file mode 100644
index 000000000000..1141bf7a332c
--- /dev/null
+++ b/sdk/aws-sigv4/benches/hmac.rs
@@ -0,0 +1,69 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+use criterion::{criterion_group, criterion_main, Criterion};
+use hmac::digest::FixedOutput;
+use hmac::{Hmac, Mac};
+#[cfg(not(any(target_arch = "powerpc", target_arch = "powerpc64")))]
+use ring::hmac::{sign, Context, Key, HMAC_SHA256};
+use sha2::Sha256;
+
+pub fn hmac(c: &mut Criterion) {
+    c.bench_function("hmac", |b| {
+        b.iter(|| {
+            let mut mac = Hmac::<Sha256>::new_from_slice(b"secret").unwrap();
+
+            mac.update(b"hello, world");
+            mac.finalize_fixed()
+        })
+    });
+}
+
+#[cfg(not(any(target_arch = "powerpc", target_arch = "powerpc64")))]
+pub fn ring_multipart(c: &mut Criterion) {
+    c.bench_function("ring_multipart", |b| {
+        b.iter(|| {
+            let k = Key::new(HMAC_SHA256, b"secret");
+            let mut ctx = Context::with_key(&k);
+
+            for slice in ["hello", ", ", "world"] {
+                ctx.update(slice.as_ref());
+            }
+
+            ctx.sign()
+        })
+    });
+}
+
+#[cfg(not(any(target_arch = "powerpc", target_arch = "powerpc64")))]
+pub fn ring_one_shot(c: &mut Criterion) {
+    c.bench_function("ring_one_shot", |b| {
+        b.iter(|| {
+            let k = Key::new(HMAC_SHA256, b"secret");
+
+            sign(&k, b"hello, world")
+        })
+    });
+}
+
+#[cfg(not(any(target_arch = "powerpc", target_arch = "powerpc64")))]
+criterion_group! {
+    name = benches;
+
+    config = Criterion::default();
+
+    targets = hmac, ring_multipart, ring_one_shot
+}
+
+#[cfg(any(target_arch = "powerpc", target_arch = "powerpc64"))]
+criterion_group! {
+    name = benches;
+
+    config = Criterion::default();
+
+    targets = hmac
+}
+
+criterion_main!(benches);
diff --git a/sdk/aws-sigv4/external-types.toml b/sdk/aws-sigv4/external-types.toml
index caecac160622..9139940c26ac 100644
--- a/sdk/aws-sigv4/external-types.toml
+++ b/sdk/aws-sigv4/external-types.toml
@@ -6,9 +6,6 @@ allowed_external_types = [
     "http::request::Request",
     "http::uri::Uri",
 
-    # TODO(https://github.com/awslabs/smithy-rs/issues/1193): Don't expose on `ring`
-    "ring::hmac::Tag",
-
     # TODO(https://github.com/awslabs/smithy-rs/issues/1193): Once tooling permits it, only allow the following types in the `event-stream` feature
     "aws_smithy_eventstream::frame::Message",
 ]
diff --git a/sdk/aws-sigv4/src/date_time.rs b/sdk/aws-sigv4/src/date_time.rs
index 6d7e5e119fcf..5ddd70560765 100644
--- a/sdk/aws-sigv4/src/date_time.rs
+++ b/sdk/aws-sigv4/src/date_time.rs
@@ -95,6 +95,8 @@ mod tests {
     use crate::date_time::test_parsers::{parse_date, parse_date_time};
     use time::format_description::well_known::Rfc3339;
 
+    // TODO(https://github.com/awslabs/smithy-rs/issues/1857)
+    #[cfg(not(any(target_arch = "powerpc", target_arch = "x86")))]
     #[test]
     fn date_format() {
         let time: SystemTime = OffsetDateTime::parse("2039-02-04T23:01:09.104Z", &Rfc3339)
@@ -107,6 +109,8 @@ mod tests {
         assert_eq!("01000102", format_date(time));
     }
 
+    // TODO(https://github.com/awslabs/smithy-rs/issues/1857)
+    #[cfg(not(any(target_arch = "powerpc", target_arch = "x86")))]
     #[test]
     fn date_time_format() {
         let time: SystemTime = OffsetDateTime::parse("2039-02-04T23:01:09.104Z", &Rfc3339)
@@ -131,6 +135,8 @@ mod tests {
         assert_eq!("20150830", format_date(time));
     }
 
+    // TODO(https://github.com/awslabs/smithy-rs/issues/1857)
+    #[cfg(not(any(target_arch = "powerpc", target_arch = "x86")))]
     #[test]
     fn test_truncate_subsecs() {
         let time: SystemTime = OffsetDateTime::parse("2039-02-04T23:01:09.104Z", &Rfc3339)
diff --git a/sdk/aws-sigv4/src/sign.rs b/sdk/aws-sigv4/src/sign.rs
index 1e93989219e9..a140f6e95554 100644
--- a/sdk/aws-sigv4/src/sign.rs
+++ b/sdk/aws-sigv4/src/sign.rs
@@ -6,24 +6,24 @@
 //! Functions to create signing keys and calculate signatures.
 
 use crate::date_time::format_date;
-use ring::{
-    digest::{self},
-    hmac::{self, Key, Tag},
-};
+use hmac::{digest::FixedOutput, Hmac, Mac};
+use sha2::{Digest, Sha256};
 use std::time::SystemTime;
 
 /// HashedPayload = Lowercase(HexEncode(Hash(requestPayload)))
 #[allow(dead_code)] // Unused when compiling without certain features
 pub(crate) fn sha256_hex_string(bytes: impl AsRef<[u8]>) -> String {
-    // hex::encode returns a lowercase string
-    hex::encode(digest::digest(&digest::SHA256, bytes.as_ref()))
+    let mut hasher = Sha256::new();
+    hasher.update(bytes);
+    hex::encode(hasher.finalize_fixed())
 }
 
 /// Calculates a Sigv4 signature
-pub fn calculate_signature(signing_key: Tag, string_to_sign: &[u8]) -> String {
-    let s_key = Key::new(hmac::HMAC_SHA256, signing_key.as_ref());
-    let tag = hmac::sign(&s_key, string_to_sign);
-    hex::encode(tag)
+pub fn calculate_signature(signing_key: impl AsRef<[u8]>, string_to_sign: &[u8]) -> String {
+    let mut mac = Hmac::<Sha256>::new_from_slice(signing_key.as_ref())
+        .expect("HMAC can take key of any size");
+    mac.update(string_to_sign);
+    hex::encode(mac.finalize_fixed())
 }
 
 /// Generates a signing key for Sigv4
@@ -32,7 +32,7 @@ pub fn generate_signing_key(
     time: SystemTime,
     region: &str,
     service: &str,
-) -> hmac::Tag {
+) -> impl AsRef<[u8]> {
     // kSecret = your secret access key
     // kDate = HMAC("AWS4" + kSecret, Date)
     // kRegion = HMAC(kDate, Region)
@@ -40,20 +40,25 @@ pub fn generate_signing_key(
     // kSigning = HMAC(kService, "aws4_request")
 
     let secret = format!("AWS4{}", secret);
-    let secret = hmac::Key::new(hmac::HMAC_SHA256, secret.as_bytes());
-    let tag = hmac::sign(&secret, format_date(time).as_bytes());
+    let mut mac =
+        Hmac::<Sha256>::new_from_slice(secret.as_ref()).expect("HMAC can take key of any size");
+    mac.update(format_date(time).as_bytes());
+    let tag = mac.finalize_fixed();
 
     // sign region
-    let key = hmac::Key::new(hmac::HMAC_SHA256, tag.as_ref());
-    let tag = hmac::sign(&key, region.as_bytes());
+    let mut mac = Hmac::<Sha256>::new_from_slice(&tag).expect("HMAC can take key of any size");
+    mac.update(region.as_bytes());
+    let tag = mac.finalize_fixed();
 
     // sign service
-    let key = hmac::Key::new(hmac::HMAC_SHA256, tag.as_ref());
-    let tag = hmac::sign(&key, service.as_bytes());
+    let mut mac = Hmac::<Sha256>::new_from_slice(&tag).expect("HMAC can take key of any size");
+    mac.update(service.as_bytes());
+    let tag = mac.finalize_fixed();
 
     // sign request
-    let key = hmac::Key::new(hmac::HMAC_SHA256, tag.as_ref());
-    hmac::sign(&key, "aws4_request".as_bytes())
+    let mut mac = Hmac::<Sha256>::new_from_slice(&tag).expect("HMAC can take key of any size");
+    mac.update("aws4_request".as_bytes());
+    mac.finalize_fixed()
 }
 
 #[cfg(test)]
diff --git a/sdk/aws-smithy-checksums/src/lib.rs b/sdk/aws-smithy-checksums/src/lib.rs
index 98ed65d34c21..59a85c397ccf 100644
--- a/sdk/aws-smithy-checksums/src/lib.rs
+++ b/sdk/aws-smithy-checksums/src/lib.rs
@@ -340,6 +340,9 @@ mod tests {
         assert_eq!(decoded_checksum, expected_checksum);
     }
 
+    // TODO(https://github.com/zowens/crc32c/issues/34)
+    // TODO(https://github.com/awslabs/smithy-rs/issues/1857)
+    #[cfg(not(any(target_arch = "powerpc", target_arch = "powerpc64")))]
     #[test]
     fn test_crc32c_checksum() {
         let mut checksum = Crc32c::default();
diff --git a/sdk/aws-smithy-client/Cargo.toml b/sdk/aws-smithy-client/Cargo.toml
index 56f653514fdb..3f0a2f902c15 100644
--- a/sdk/aws-smithy-client/Cargo.toml
+++ b/sdk/aws-smithy-client/Cargo.toml
@@ -54,13 +54,13 @@ version = "0.51.0"
 
 [dependencies.hyper]
 version = "0.14.12"
-features = ["client", "http2", "http1"]
+features = ["client", "http2", "http1", "tcp"]
 optional = true
 
 [dependencies.hyper-rustls]
 version = "0.23.0"
 optional = true
-features = ["rustls-native-certs", "http2"]
+features = ["rustls-native-certs", "http2", "webpki-roots"]
 
 [dependencies.hyper-tls]
 version = "0.5.0"
@@ -91,10 +91,6 @@ path = "../aws-smithy-async"
 features = ["rt-tokio"]
 version = "0.51.0"
 
-[dev-dependencies.hyper-rustls]
-version = "0.23.0"
-features = ["webpki-roots"]
-
 [dev-dependencies.serde]
 version = "1"
 features = ["derive"]
diff --git a/sdk/aws-smithy-types/src/date_time/mod.rs b/sdk/aws-smithy-types/src/date_time/mod.rs
index bb1120c8298b..bf8b27b1192f 100644
--- a/sdk/aws-smithy-types/src/date_time/mod.rs
+++ b/sdk/aws-smithy-types/src/date_time/mod.rs
@@ -526,6 +526,8 @@ mod test {
         assert!(DateTime::from_nanos(10_000_000_000_000_000_000_999_999_999_i128).is_err());
     }
 
+    // TODO(https://github.com/awslabs/smithy-rs/issues/1857)
+    #[cfg(not(any(target_arch = "powerpc", target_arch = "x86")))]
     #[test]
     fn system_time_conversions() {
         // Check agreement
diff --git a/versions.toml b/versions.toml
index c8cd302c0661..87fc3bbf9a82 100644
--- a/versions.toml
+++ b/versions.toml
@@ -1,4 +1,4 @@
-smithy_rs_revision = '6b3e31123571ec64656724c94c50415a2b2e0aab'
+smithy_rs_revision = '7e666dab8bbec977ff88dd885cd7d50c31a10908'
 aws_doc_sdk_examples_revision = 'f88a0edba3961f9d978bf1727054c9414e4fca2b'
 
 [manual_interventions]
@@ -1921,7 +1921,7 @@ source_hash = 'e85895bbe46b96359ca3f040197e39feee127491eea6dff5353bfea316e2cc13'
 [crates.aws-sigv4]
 category = 'AwsRuntime'
 version = '0.51.0'
-source_hash = '50462d0f34c6e69dec204a4402600c45c3fee7ce2881939b78ee2c0182d35360'
+source_hash = 'a90f3a3a415f816929d8bc1a0ca26c3f616ce97e886e0cec5f08cd43bb4d3915'
 
 [crates.aws-smithy-async]
 category = 'SmithyRuntime'
@@ -1931,12 +1931,12 @@ source_hash = '85826c9beec513a917bd13d5691af14f3baabdcff7402837d2a4859b493b8b69'
 [crates.aws-smithy-checksums]
 category = 'SmithyRuntime'
 version = '0.51.0'
-source_hash = 'f0a1257468bcfa5b2a129e47bef9512258ba444b362ae84a7fcf53452d4b5388'
+source_hash = '7039fcd68d5630bbd0398f9d6f1abb25d2d41b001daa3510012a131393ecad18'
 
 [crates.aws-smithy-client]
 category = 'SmithyRuntime'
 version = '0.51.0'
-source_hash = '065493c6ebb0e87a3ecee96704a1739d0fa7876bbd73f409ecb852c9df855cf8'
+source_hash = 'b778d51593083a4cd5676d8b77beced8c5feda67cc52fe453b1d6f27e0975d52'
 
 [crates.aws-smithy-eventstream]
 category = 'SmithyRuntime'
@@ -1971,7 +1971,7 @@ source_hash = '774f83e0e31d9f4c0f1158e87c39438d60280bac0f2e1e1ef1d993bc9594cc25'
 [crates.aws-smithy-types]
 category = 'SmithyRuntime'
 version = '0.51.0'
-source_hash = '190fb14415d84f16856d01fa9b6b275e5ce56e448dd496114cffeb5387e0e09c'
+source_hash = '468361bba3a588959443cb5fb71680a6688f7cccb2f2e3201edc9613ee6d5952'
 
 [crates.aws-smithy-types-convert]
 category = 'SmithyRuntime'