// Get signature.
	newSignature := getSignature(signingKey, formValues.Get("Policy"))

	// Verify signature.
	if !compareSignatureV4(newSignature, formValues.Get(xhttp.AmzSignature)) {
		return cred, ErrSignatureDoesNotMatch
	}

	// Success.
	return cred, ErrNone
}

// doesPresignedSignatureMatch - Verify query headers with presigned signature

			// validating the extraction/parsing of signature field.
			if !compareSignatureV4(testCase.expectedAuthField.Signature, parsedAuthField.Signature) {
				t.Errorf("Test %d: Parsed Signature field mismatch: Expected \"%s\", got \"%s\"", i+1, testCase.expectedAuthField.Signature, parsedAuthField.Signature)
			}

			// validating the extracted signed headers.

		{"X-Amz-Content-Sha256", unsignedPayload, "X-Amz-Credential", "", true},

		// Test case - 4.
		// Enabling PreSigned Signature v4, but X-Amz-Content-Sha256 not set has to be skipped.
		{"", "", "X-Amz-Credential", "", true},

		// Test case - 5.
		// Enabling PreSigned Signature v4, but X-Amz-Content-Sha256 set and its not UNSIGNED-PAYLOAD, we shouldn't skip.

    } else {
      // Everything else requires Android API 21+.
      signature(rootProject.libs.signature.android.apilevel21) { artifact { type = "signature" } }
    }

    // OkHttp requires Java 8+.
    signature(rootProject.libs.codehaus.signature.java18) { artifact { type = "signature" } }
  }

  tasks.withType<KotlinCompile> {
    kotlinOptions {
      jvmTarget = JavaVersion.VERSION_1_8.toString()

	req.URL.RawQuery = query.Encode()

	// Save signature finally.
	req.URL.RawQuery += "&Signature=" + url.QueryEscape(signature)
	return nil
}

// Sign given request using Signature V2.
func signRequestV2(req *http.Request, accessKey, secretKey string) error {
	signer.SignV2(*req, accessKey, secretKey, false)
	return nil
}

// Sign given request using Signature V4.

    path_param_names = get_path_param_names(path)
    endpoint_signature = get_typed_signature(call)
    signature_params = endpoint_signature.parameters
    dependant = Dependant(
        call=call,
        name=name,
        path=path,
        security_scopes=security_scopes,
        use_cache=use_cache,
    )
    for param_name, param in signature_params.items():
        is_path_param = param_name in path_param_names

pkg go/types, method (*Func) Signature() *Signature #65772...

import org.jetbrains.kotlin.analysis.api.lifetime.KtLifetimeToken
import org.jetbrains.kotlin.analysis.api.signatures.KtCallableSignature
import org.jetbrains.kotlin.analysis.api.signatures.KtFunctionLikeSignature
import org.jetbrains.kotlin.analysis.api.signatures.KtVariableLikeSignature
import org.jetbrains.kotlin.analysis.api.symbols.*
import org.jetbrains.kotlin.analysis.api.types.KtType

	}
}

// postPresignSignatureV4 - presigned signature for PostPolicy requests.
func postPresignSignatureV4(policyBase64 string, t time.Time, secretAccessKey, location string) string {
	// Get signining key.
	signingkey := getSigningKey(secretAccessKey, t, location, "s3")
	// Calculate signature.
	signature := getSignature(signingkey, policyBase64)
	return signature
}

robolectric-android = "org.robolectric:android-all:14-robolectric-10818077"
robolectric = "org.robolectric:robolectric:4.12.1"
signature-android-apilevel21 = "net.sf.androidscents.signature:android-api-level-21:5.0.1_r2"
signature-android-apilevel24 = "net.sf.androidscents.signature:android-api-level-24:7.0_r2"
squareup-moshi = { module = "com.squareup.moshi:moshi", version.ref = "com-squareup-moshi" }