Fix: restore ReadEnclavePrivateKey function

Author: distraw

cmd/util/integrityattestation/utils.go

@@ -0,0 +1,45 @@
+package integrityattestation
+
+import (
+	"context"
+	"crypto/ecdsa"
+	"fmt"
+	"os"
+
+	awsconfig "github.com/aws/aws-sdk-go-v2/config"
+	"github.com/distributed-lab/enclave-extras/nitro"
+
+	"github.com/offchainlabs/nitro/util/signature"
+)
+
+func ReadEnclavePrivateKey(attestationsPath string) (*ecdsa.PrivateKey, signature.DataSignerFunc, error) {
+	if err := os.MkdirAll(attestationsPath, os.ModePerm); err != nil {
+		return nil, nil, fmt.Errorf("failed to create attestations path directory %s with error: %w", attestationsPath, err)
+	}
+
+	awsConfig, err := awsconfig.LoadDefaultConfig(context.Background())
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to load AWS config: %w", err)
+	}
+
+	kmsKeyID, err := nitro.GetAttestedKMSKeyID(awsConfig, attestationsPath)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to get attested KMS Key ID: %w", err)
+	}
+
+	privateKey, err := nitro.GetAttestedPrivateKey(awsConfig, kmsKeyID, attestationsPath)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to get attested private key: %w", err)
+	}
+
+	publicKey, err := nitro.GetAttestedPublicKey(privateKey, attestationsPath)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to get attested public key: %w", err)
+	}
+
+	if _, err = nitro.GetAttestedAddress(publicKey, attestationsPath); err != nil {
+		return nil, nil, fmt.Errorf("failed to get attested address: %w", err)
+	}
+
+	return privateKey, signature.DataSignerFromPrivateKey(privateKey), nil
+}