diff --git a/minui/graphics_drm.cpp b/minui/graphics_drm.cpp
index 81b49fd..f81fd9d 100644
--- a/minui/graphics_drm.cpp
+++ b/minui/graphics_drm.cpp
@@ -24,74 +24,37 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <memory>
+
+#include <android-base/macros.h>
+#include <android-base/stringprintf.h>
+#include <android-base/unique_fd.h>
 #include <drm_fourcc.h>
 #include <xf86drm.h>
 #include <xf86drmMode.h>
 
 #include "minui/minui.h"
 
-#define ARRAY_SIZE(A) (sizeof(A)/sizeof(*(A)))
-
-MinuiBackendDrm::MinuiBackendDrm()
-    : GRSurfaceDrms(), main_monitor_crtc(nullptr), main_monitor_connector(nullptr), drm_fd(-1) {}
-
-void MinuiBackendDrm::DrmDisableCrtc(int drm_fd, drmModeCrtc* crtc) {
-  if (crtc) {
-    drmModeSetCrtc(drm_fd, crtc->crtc_id,
-                   0,         // fb_id
-                   0, 0,      // x,y
-                   nullptr,   // connectors
-                   0,         // connector_count
-                   nullptr);  // mode
-  }
-}
-
-int MinuiBackendDrm::DrmEnableCrtc(int drm_fd, drmModeCrtc* crtc, GRSurfaceDrm* surface) {
-  int ret = drmModeSetCrtc(drm_fd, crtc->crtc_id, surface->fb_id, 0, 0,  // x,y
-                           &main_monitor_connector->connector_id,
-                           1,  // connector_count
-                           &main_monitor_crtc->mode);
-
-  if (ret) {
-    printf("drmModeSetCrtc failed ret=%d\n", ret);
+GRSurfaceDrm::~GRSurfaceDrm() {
+  if (mmapped_buffer_) {
+    munmap(mmapped_buffer_, row_bytes * height);
   }
 
-  return ret;
-}
-
-void MinuiBackendDrm::Blank(bool blank) {
-  if (blank) {
-    DrmDisableCrtc(drm_fd, main_monitor_crtc);
-  } else {
-    DrmEnableCrtc(drm_fd, main_monitor_crtc, GRSurfaceDrms[current_buffer]);
-  }
-}
-
-void MinuiBackendDrm::DrmDestroySurface(GRSurfaceDrm* surface) {
-  if (!surface) return;
-
-  if (surface->mmapped_buffer_) {
-    munmap(surface->mmapped_buffer_, surface->row_bytes * surface->height);
-  }
-
-  if (surface->fb_id) {
-    int ret = drmModeRmFB(drm_fd, surface->fb_id);
-    if (ret) {
-      printf("drmModeRmFB failed ret=%d\n", ret);
+  if (fb_id) {
+    if (drmModeRmFB(drm_fd_, fb_id) != 0) {
+      perror("Failed to drmModeRmFB");
+      // Falling through to free other resources.
     }
   }
 
-  if (surface->handle) {
+  if (handle) {
     drm_gem_close gem_close = {};
-    gem_close.handle = surface->handle;
+    gem_close.handle = handle;
 
-    int ret = drmIoctl(drm_fd, DRM_IOCTL_GEM_CLOSE, &gem_close);
-    if (ret) {
-      printf("DRM_IOCTL_GEM_CLOSE failed ret=%d\n", ret);
+    if (drmIoctl(drm_fd_, DRM_IOCTL_GEM_CLOSE, &gem_close) != 0) {
+      perror("Failed to DRM_IOCTL_GEM_CLOSE");
     }
   }
-
-  delete surface;
 }
 
 static int drm_format_to_bpp(uint32_t format) {
@@ -111,10 +74,7 @@
   }
 }
 
-GRSurfaceDrm* MinuiBackendDrm::DrmCreateSurface(int width, int height) {
-  GRSurfaceDrm* surface = new GRSurfaceDrm;
-  *surface = {};
-
+std::unique_ptr<GRSurfaceDrm> GRSurfaceDrm::Create(int drm_fd, int width, int height) {
   uint32_t format;
   PixelFormat pixel_format = gr_pixel_format();
   // PixelFormat comes in byte order, whereas DRM_FORMAT_* uses little-endian
@@ -137,12 +97,12 @@
   create_dumb.bpp = drm_format_to_bpp(format);
   create_dumb.flags = 0;
 
-  int ret = drmIoctl(drm_fd, DRM_IOCTL_MODE_CREATE_DUMB, &create_dumb);
-  if (ret) {
-    printf("DRM_IOCTL_MODE_CREATE_DUMB failed ret=%d\n", ret);
-    DrmDestroySurface(surface);
+  if (drmIoctl(drm_fd, DRM_IOCTL_MODE_CREATE_DUMB, &create_dumb) != 0) {
+    perror("Failed to DRM_IOCTL_MODE_CREATE_DUMB");
     return nullptr;
   }
+
+  std::unique_ptr<GRSurfaceDrm> surface = std::make_unique<GRSurfaceDrm>(drm_fd);
   surface->handle = create_dumb.handle;
 
   uint32_t handles[4], pitches[4], offsets[4];
@@ -151,20 +111,16 @@
   pitches[0] = create_dumb.pitch;
   offsets[0] = 0;
 
-  ret =
-      drmModeAddFB2(drm_fd, width, height, format, handles, pitches, offsets, &(surface->fb_id), 0);
-  if (ret) {
-    printf("drmModeAddFB2 failed ret=%d\n", ret);
-    DrmDestroySurface(surface);
+  if (drmModeAddFB2(drm_fd, width, height, format, handles, pitches, offsets, &surface->fb_id, 0) !=
+      0) {
+    perror("Failed to drmModeAddFB2");
     return nullptr;
   }
 
   drm_mode_map_dumb map_dumb = {};
   map_dumb.handle = create_dumb.handle;
-  ret = drmIoctl(drm_fd, DRM_IOCTL_MODE_MAP_DUMB, &map_dumb);
-  if (ret) {
-    printf("DRM_IOCTL_MODE_MAP_DUMB failed ret=%d\n", ret);
-    DrmDestroySurface(surface);
+  if (drmIoctl(drm_fd, DRM_IOCTL_MODE_MAP_DUMB, &map_dumb) != 0) {
+    perror("Failed to DRM_IOCTL_MODE_MAP_DUMB");
     return nullptr;
   }
 
@@ -175,14 +131,44 @@
   auto mmapped = mmap(nullptr, surface->height * surface->row_bytes, PROT_READ | PROT_WRITE,
                       MAP_SHARED, drm_fd, map_dumb.offset);
   if (mmapped == MAP_FAILED) {
-    perror("mmap() failed");
-    DrmDestroySurface(surface);
+    perror("Failed to mmap()");
     return nullptr;
   }
   surface->mmapped_buffer_ = static_cast<uint8_t*>(mmapped);
   return surface;
 }
 
+void MinuiBackendDrm::DrmDisableCrtc(int drm_fd, drmModeCrtc* crtc) {
+  if (crtc) {
+    drmModeSetCrtc(drm_fd, crtc->crtc_id,
+                   0,         // fb_id
+                   0, 0,      // x,y
+                   nullptr,   // connectors
+                   0,         // connector_count
+                   nullptr);  // mode
+  }
+}
+
+bool MinuiBackendDrm::DrmEnableCrtc(int drm_fd, drmModeCrtc* crtc,
+                                    const std::unique_ptr<GRSurfaceDrm>& surface) {
+  if (drmModeSetCrtc(drm_fd, crtc->crtc_id, surface->fb_id, 0, 0,  // x,y
+                     &main_monitor_connector->connector_id,
+                     1,  // connector_count
+                     &main_monitor_crtc->mode) != 0) {
+    perror("Failed to drmModeSetCrtc");
+    return false;
+  }
+  return true;
+}
+
+void MinuiBackendDrm::Blank(bool blank) {
+  if (blank) {
+    DrmDisableCrtc(drm_fd, main_monitor_crtc);
+  } else {
+    DrmEnableCrtc(drm_fd, main_monitor_crtc, GRSurfaceDrms[current_buffer]);
+  }
+}
+
 static drmModeCrtc* find_crtc_for_connector(int fd, drmModeRes* resources,
                                             drmModeConnector* connector) {
   // Find the encoder. If we already have one, just use it.
@@ -264,7 +250,7 @@
   do {
     main_monitor_connector = find_used_connector_by_type(fd, resources, kConnectorPriority[i]);
     i++;
-  } while (!main_monitor_connector && i < ARRAY_SIZE(kConnectorPriority));
+  } while (!main_monitor_connector && i < arraysize(kConnectorPriority));
 
   /* If we didn't find a connector, grab the first one that is connected. */
   if (!main_monitor_connector) {
@@ -298,60 +284,53 @@
 
 GRSurface* MinuiBackendDrm::Init() {
   drmModeRes* res = nullptr;
+  drm_fd = -1;
 
   /* Consider DRM devices in order. */
   for (int i = 0; i < DRM_MAX_MINOR; i++) {
-    char* dev_name;
-    int ret = asprintf(&dev_name, DRM_DEV_NAME, DRM_DIR_NAME, i);
-    if (ret < 0) continue;
+    auto dev_name = android::base::StringPrintf(DRM_DEV_NAME, DRM_DIR_NAME, i);
+    android::base::unique_fd fd(open(dev_name.c_str(), O_RDWR));
+    if (fd == -1) continue;
 
-    drm_fd = open(dev_name, O_RDWR, 0);
-    free(dev_name);
-    if (drm_fd < 0) continue;
-
-    uint64_t cap = 0;
     /* We need dumb buffers. */
-    ret = drmGetCap(drm_fd, DRM_CAP_DUMB_BUFFER, &cap);
-    if (ret || cap == 0) {
-      close(drm_fd);
+    if (uint64_t cap = 0; drmGetCap(fd.get(), DRM_CAP_DUMB_BUFFER, &cap) != 0 || cap == 0) {
       continue;
     }
 
-    res = drmModeGetResources(drm_fd);
+    res = drmModeGetResources(fd.get());
     if (!res) {
-      close(drm_fd);
       continue;
     }
 
     /* Use this device if it has at least one connected monitor. */
     if (res->count_crtcs > 0 && res->count_connectors > 0) {
-      if (find_first_connected_connector(drm_fd, res)) break;
+      if (find_first_connected_connector(fd.get(), res)) {
+        drm_fd = fd.release();
+        break;
+      }
     }
 
     drmModeFreeResources(res);
-    close(drm_fd);
     res = nullptr;
   }
 
-  if (drm_fd < 0 || res == nullptr) {
-    perror("cannot find/open a drm device");
+  if (drm_fd == -1 || res == nullptr) {
+    perror("Failed to find/open a drm device");
     return nullptr;
   }
 
   uint32_t selected_mode;
   main_monitor_connector = FindMainMonitor(drm_fd, res, &selected_mode);
-
   if (!main_monitor_connector) {
-    printf("main_monitor_connector not found\n");
+    fprintf(stderr, "Failed to find main_monitor_connector\n");
     drmModeFreeResources(res);
     close(drm_fd);
     return nullptr;
   }
 
   main_monitor_crtc = find_crtc_for_connector(drm_fd, res, main_monitor_connector);
-
   if (!main_monitor_crtc) {
-    printf("main_monitor_crtc not found\n");
+    fprintf(stderr, "Failed to find main_monitor_crtc\n");
     drmModeFreeResources(res);
     close(drm_fd);
     return nullptr;
@@ -366,21 +345,20 @@
 
   drmModeFreeResources(res);
 
-  GRSurfaceDrms[0] = DrmCreateSurface(width, height);
-  GRSurfaceDrms[1] = DrmCreateSurface(width, height);
+  GRSurfaceDrms[0] = GRSurfaceDrm::Create(drm_fd, width, height);
+  GRSurfaceDrms[1] = GRSurfaceDrm::Create(drm_fd, width, height);
   if (!GRSurfaceDrms[0] || !GRSurfaceDrms[1]) {
-    // GRSurfaceDrms and drm_fd should be freed in d'tor.
     return nullptr;
   }
 
   current_buffer = 0;
 
   // We will likely encounter errors in the backend functions (i.e. Flip) if EnableCrtc fails.
-  if (DrmEnableCrtc(drm_fd, main_monitor_crtc, GRSurfaceDrms[1]) != 0) {
+  if (!DrmEnableCrtc(drm_fd, main_monitor_crtc, GRSurfaceDrms[1])) {
     return nullptr;
   }
 
-  return GRSurfaceDrms[0];
+  return GRSurfaceDrms[0].get();
 }
 
 static void page_flip_complete(__unused int fd,
@@ -393,12 +371,9 @@
 
 GRSurface* MinuiBackendDrm::Flip() {
   bool ongoing_flip = true;
-
-  int ret = drmModePageFlip(drm_fd, main_monitor_crtc->crtc_id,
-                            GRSurfaceDrms[current_buffer]->fb_id,
-                            DRM_MODE_PAGE_FLIP_EVENT, &ongoing_flip);
-  if (ret < 0) {
-    printf("drmModePageFlip failed ret=%d\n", ret);
+  if (drmModePageFlip(drm_fd, main_monitor_crtc->crtc_id, GRSurfaceDrms[current_buffer]->fb_id,
+                      DRM_MODE_PAGE_FLIP_EVENT, &ongoing_flip) != 0) {
+    perror("Failed to drmModePageFlip");
     return nullptr;
   }
 
@@ -408,9 +383,8 @@
       .events = POLLIN
     };
 
-    ret = poll(&fds, 1, -1);
-    if (ret == -1 || !(fds.revents & POLLIN)) {
-      printf("poll() failed on drm fd\n");
+    if (poll(&fds, 1, -1) == -1 || !(fds.revents & POLLIN)) {
+      perror("Failed to poll() on drm fd");
       break;
     }
 
@@ -419,21 +393,18 @@
       .page_flip_handler = page_flip_complete
     };
 
-    ret = drmHandleEvent(drm_fd, &evctx);
-    if (ret != 0) {
-      printf("drmHandleEvent failed ret=%d\n", ret);
+    if (drmHandleEvent(drm_fd, &evctx) != 0) {
+      perror("Failed to drmHandleEvent");
       break;
     }
   }
 
   current_buffer = 1 - current_buffer;
-  return GRSurfaceDrms[current_buffer];
+  return GRSurfaceDrms[current_buffer].get();
 }
 
 MinuiBackendDrm::~MinuiBackendDrm() {
   DrmDisableCrtc(drm_fd, main_monitor_crtc);
-  DrmDestroySurface(GRSurfaceDrms[0]);
-  DrmDestroySurface(GRSurfaceDrms[1]);
   drmModeFreeCrtc(main_monitor_crtc);
   drmModeFreeConnector(main_monitor_connector);
   close(drm_fd);
diff --git a/minui/graphics_drm.h b/minui/graphics_drm.h
index f3aad6b..02db89f 100644
--- a/minui/graphics_drm.h
+++ b/minui/graphics_drm.h
@@ -18,6 +18,9 @@
 
 #include <stdint.h>
 
+#include <memory>
+
+#include <android-base/macros.h>
 #include <xf86drmMode.h>
 
 #include "graphics.h"
@@ -25,6 +28,12 @@
 
 class GRSurfaceDrm : public GRSurface {
  public:
+  explicit GRSurfaceDrm(int drm_fd) : drm_fd_(drm_fd) {}
+  ~GRSurfaceDrm() override;
+
+  // Creates a GRSurfaceDrm instance.
+  static std::unique_ptr<GRSurfaceDrm> Create(int drm_fd, int width, int height);
+
   uint8_t* data() override {
     return mmapped_buffer_;
   }
@@ -32,30 +41,33 @@
  private:
   friend class MinuiBackendDrm;
 
-  uint32_t fb_id;
-  uint32_t handle;
+  const int drm_fd_;
+
+  uint32_t fb_id{ 0 };
+  uint32_t handle{ 0 };
   uint8_t* mmapped_buffer_{ nullptr };
+
+  DISALLOW_COPY_AND_ASSIGN(GRSurfaceDrm);
 };
 
 class MinuiBackendDrm : public MinuiBackend {
  public:
+  MinuiBackendDrm() = default;
+  ~MinuiBackendDrm() override;
+
   GRSurface* Init() override;
   GRSurface* Flip() override;
   void Blank(bool) override;
-  ~MinuiBackendDrm() override;
-  MinuiBackendDrm();
 
  private:
   void DrmDisableCrtc(int drm_fd, drmModeCrtc* crtc);
-  int DrmEnableCrtc(int drm_fd, drmModeCrtc* crtc, GRSurfaceDrm* surface);
-  GRSurfaceDrm* DrmCreateSurface(int width, int height);
-  void DrmDestroySurface(GRSurfaceDrm* surface);
+  bool DrmEnableCrtc(int drm_fd, drmModeCrtc* crtc, const std::unique_ptr<GRSurfaceDrm>& surface);
   void DisableNonMainCrtcs(int fd, drmModeRes* resources, drmModeCrtc* main_crtc);
   drmModeConnector* FindMainMonitor(int fd, drmModeRes* resources, uint32_t* mode_index);
 
-  GRSurfaceDrm* GRSurfaceDrms[2];
-  int current_buffer;
-  drmModeCrtc* main_monitor_crtc;
-  drmModeConnector* main_monitor_connector;
-  int drm_fd;
+  std::unique_ptr<GRSurfaceDrm> GRSurfaceDrms[2];
+  int current_buffer{ 0 };
+  drmModeCrtc* main_monitor_crtc{ nullptr };
+  drmModeConnector* main_monitor_connector{ nullptr };
+  int drm_fd{ -1 };
 };
diff --git a/tests/component/verifier_test.cpp b/tests/component/verifier_test.cpp
index d110c37..480f3c9 100644
--- a/tests/component/verifier_test.cpp
+++ b/tests/component/verifier_test.cpp
@@ -30,6 +30,9 @@
 #include <android-base/test_utils.h>
 #include <android-base/unique_fd.h>
 #include <gtest/gtest.h>
+#include <openssl/bn.h>
+#include <openssl/ec.h>
+#include <openssl/nid.h>
 #include <ziparchive/zip_writer.h>
 
 #include "common/test_constants.h"
@@ -148,6 +151,35 @@
   VerifyPackageWithSingleCertificate("otasigned_v5.zip", std::move(cert));
 }
 
+TEST(VerifierTest, LoadCertificateFromBuffer_check_rsa_keys) {
+  std::unique_ptr<RSA, RSADeleter> rsa(RSA_new());
+  std::unique_ptr<BIGNUM, decltype(&BN_free)> exponent(BN_new(), BN_free);
+  BN_set_word(exponent.get(), 3);
+  RSA_generate_key_ex(rsa.get(), 2048, exponent.get(), nullptr);
+  ASSERT_TRUE(CheckRSAKey(rsa));
+
+  // Exponent is expected to be 3 or 65537
+  BN_set_word(exponent.get(), 17);
+  RSA_generate_key_ex(rsa.get(), 2048, exponent.get(), nullptr);
+  ASSERT_FALSE(CheckRSAKey(rsa));
+
+  // Modulus is expected to be 2048.
+  BN_set_word(exponent.get(), 3);
+  RSA_generate_key_ex(rsa.get(), 1024, exponent.get(), nullptr);
+  ASSERT_FALSE(CheckRSAKey(rsa));
+}
+
+TEST(VerifierTest, LoadCertificateFromBuffer_check_ec_keys) {
+  std::unique_ptr<EC_KEY, ECKEYDeleter> ec(EC_KEY_new_by_curve_name(NID_X9_62_prime256v1));
+  ASSERT_EQ(1, EC_KEY_generate_key(ec.get()));
+  ASSERT_TRUE(CheckECKey(ec));
+
+  // Expects 256-bit EC key with curve NIST P-256
+  ec.reset(EC_KEY_new_by_curve_name(NID_secp224r1));
+  ASSERT_EQ(1, EC_KEY_generate_key(ec.get()));
+  ASSERT_FALSE(CheckECKey(ec));
+}
+
 TEST(VerifierTest, LoadKeysFromZipfile_empty_archive) {
   TemporaryFile otacerts;
   BuildCertificateArchive({}, otacerts.release());
@@ -206,8 +238,9 @@
     }
 
     for (auto it = ++args.cbegin(); it != args.cend(); ++it) {
-      std::string public_key_file = from_testdata_base("testkey_" + *it + ".txt");
-      ASSERT_TRUE(load_keys(public_key_file.c_str(), certs));
+      std::string public_key_file = from_testdata_base("testkey_" + *it + ".x509.pem");
+      certs.emplace_back(0, Certificate::KEY_TYPE_RSA, nullptr, nullptr);
+      LoadKeyFromFile(public_key_file, &certs.back());
     }
   }
 
@@ -221,70 +254,10 @@
 class VerifierFailureTest : public VerifierTest {
 };
 
-TEST(VerifierTest, load_keys_multiple_keys) {
-  std::string testkey_v4;
-  ASSERT_TRUE(android::base::ReadFileToString(from_testdata_base("testkey_v4.txt"), &testkey_v4));
-
-  std::string testkey_v3;
-  ASSERT_TRUE(android::base::ReadFileToString(from_testdata_base("testkey_v3.txt"), &testkey_v3));
-
-  std::string keys = testkey_v4 + "," + testkey_v3 + "," + testkey_v4;
-  TemporaryFile key_file1;
-  ASSERT_TRUE(android::base::WriteStringToFile(keys, key_file1.path));
-  std::vector<Certificate> certs;
-  ASSERT_TRUE(load_keys(key_file1.path, certs));
-  ASSERT_EQ(3U, certs.size());
-}
-
-TEST(VerifierTest, load_keys_invalid_keys) {
-  std::vector<Certificate> certs;
-  ASSERT_FALSE(load_keys("/doesntexist", certs));
-
-  // Empty file.
-  TemporaryFile key_file1;
-  ASSERT_FALSE(load_keys(key_file1.path, certs));
-
-  // Invalid contents.
-  ASSERT_TRUE(android::base::WriteStringToFile("invalid", key_file1.path));
-  ASSERT_FALSE(load_keys(key_file1.path, certs));
-
-  std::string testkey_v4;
-  ASSERT_TRUE(android::base::ReadFileToString(from_testdata_base("testkey_v4.txt"), &testkey_v4));
-
-  // Invalid key version: "v4 ..." => "v6 ...".
-  std::string invalid_key2(testkey_v4);
-  invalid_key2[1] = '6';
-  TemporaryFile key_file2;
-  ASSERT_TRUE(android::base::WriteStringToFile(invalid_key2, key_file2.path));
-  ASSERT_FALSE(load_keys(key_file2.path, certs));
-
-  // Invalid key content: inserted extra bytes ",2209831334".
-  std::string invalid_key3(testkey_v4);
-  invalid_key3.insert(invalid_key2.size() - 2, ",2209831334");
-  TemporaryFile key_file3;
-  ASSERT_TRUE(android::base::WriteStringToFile(invalid_key3, key_file3.path));
-  ASSERT_FALSE(load_keys(key_file3.path, certs));
-
-  // Invalid key: the last key must not end with an extra ','.
-  std::string invalid_key4 = testkey_v4 + ",";
-  TemporaryFile key_file4;
-  ASSERT_TRUE(android::base::WriteStringToFile(invalid_key4, key_file4.path));
-  ASSERT_FALSE(load_keys(key_file4.path, certs));
-
-  // Invalid key separator.
-  std::string invalid_key5 = testkey_v4 + ";" + testkey_v4;
-  TemporaryFile key_file5;
-  ASSERT_TRUE(android::base::WriteStringToFile(invalid_key5, key_file5.path));
-  ASSERT_FALSE(load_keys(key_file5.path, certs));
-}
-
 TEST(VerifierTest, BadPackage_AlteredFooter) {
-  std::string testkey_v3;
-  ASSERT_TRUE(android::base::ReadFileToString(from_testdata_base("testkey_v3.txt"), &testkey_v3));
-  TemporaryFile key_file1;
-  ASSERT_TRUE(android::base::WriteStringToFile(testkey_v3, key_file1.path));
   std::vector<Certificate> certs;
-  ASSERT_TRUE(load_keys(key_file1.path, certs));
+  certs.emplace_back(0, Certificate::KEY_TYPE_RSA, nullptr, nullptr);
+  LoadKeyFromFile(from_testdata_base("testkey_v3.x509.pem"), &certs.back());
 
   std::string package;
   ASSERT_TRUE(android::base::ReadFileToString(from_testdata_base("otasigned_v3.zip"), &package));
@@ -298,12 +271,9 @@
 }
 
 TEST(VerifierTest, BadPackage_AlteredContent) {
-  std::string testkey_v3;
-  ASSERT_TRUE(android::base::ReadFileToString(from_testdata_base("testkey_v3.txt"), &testkey_v3));
-  TemporaryFile key_file1;
-  ASSERT_TRUE(android::base::WriteStringToFile(testkey_v3, key_file1.path));
   std::vector<Certificate> certs;
-  ASSERT_TRUE(load_keys(key_file1.path, certs));
+  certs.emplace_back(0, Certificate::KEY_TYPE_RSA, nullptr, nullptr);
+  LoadKeyFromFile(from_testdata_base("testkey_v3.x509.pem"), &certs.back());
 
   std::string package;
   ASSERT_TRUE(android::base::ReadFileToString(from_testdata_base("otasigned_v3.zip"), &package));
@@ -324,13 +294,9 @@
 }
 
 TEST(VerifierTest, BadPackage_SignatureStartOutOfBounds) {
-  std::string testkey_v3;
-  ASSERT_TRUE(android::base::ReadFileToString(from_testdata_base("testkey_v3.txt"), &testkey_v3));
-
-  TemporaryFile key_file;
-  ASSERT_TRUE(android::base::WriteStringToFile(testkey_v3, key_file.path));
   std::vector<Certificate> certs;
-  ASSERT_TRUE(load_keys(key_file.path, certs));
+  certs.emplace_back(0, Certificate::KEY_TYPE_RSA, nullptr, nullptr);
+  LoadKeyFromFile(from_testdata_base("testkey_v3.x509.pem"), &certs.back());
 
   // Signature start is 65535 (0xffff) while comment size is 0 (Bug: 31914369).
   std::string package = "\x50\x4b\x05\x06"s + std::string(12, '\0') + "\xff\xff\xff\xff\x00\x00"s;
diff --git a/verifier.cpp b/verifier.cpp
index 2101dcb..44bd4e1 100644
--- a/verifier.cpp
+++ b/verifier.cpp
@@ -308,144 +308,6 @@
   return VERIFY_FAILURE;
 }
 
-std::unique_ptr<RSA, RSADeleter> parse_rsa_key(FILE* file, uint32_t exponent) {
-    // Read key length in words and n0inv. n0inv is a precomputed montgomery
-    // parameter derived from the modulus and can be used to speed up
-    // verification. n0inv is 32 bits wide here, assuming the verification logic
-    // uses 32 bit arithmetic. However, BoringSSL may use a word size of 64 bits
-    // internally, in which case we don't have a valid n0inv. Thus, we just
-    // ignore the montgomery parameters and have BoringSSL recompute them
-    // internally. If/When the speedup from using the montgomery parameters
-    // becomes relevant, we can add more sophisticated code here to obtain a
-    // 64-bit n0inv and initialize the montgomery parameters in the key object.
-    uint32_t key_len_words = 0;
-    uint32_t n0inv = 0;
-    if (fscanf(file, " %i , 0x%x", &key_len_words, &n0inv) != 2) {
-        return nullptr;
-    }
-
-    if (key_len_words > 8192 / 32) {
-        LOG(ERROR) << "key length (" << key_len_words << ") too large";
-        return nullptr;
-    }
-
-    // Read the modulus.
-    std::unique_ptr<uint32_t[]> modulus(new uint32_t[key_len_words]);
-    if (fscanf(file, " , { %u", &modulus[0]) != 1) {
-        return nullptr;
-    }
-    for (uint32_t i = 1; i < key_len_words; ++i) {
-        if (fscanf(file, " , %u", &modulus[i]) != 1) {
-            return nullptr;
-        }
-    }
-
-    // Cconvert from little-endian array of little-endian words to big-endian
-    // byte array suitable as input for BN_bin2bn.
-    std::reverse((uint8_t*)modulus.get(),
-                 (uint8_t*)(modulus.get() + key_len_words));
-
-    // The next sequence of values is the montgomery parameter R^2. Since we
-    // generally don't have a valid |n0inv|, we ignore this (see comment above).
-    uint32_t rr_value;
-    if (fscanf(file, " } , { %u", &rr_value) != 1) {
-        return nullptr;
-    }
-    for (uint32_t i = 1; i < key_len_words; ++i) {
-        if (fscanf(file, " , %u", &rr_value) != 1) {
-            return nullptr;
-        }
-    }
-    if (fscanf(file, " } } ") != 0) {
-        return nullptr;
-    }
-
-    // Initialize the key.
-    std::unique_ptr<RSA, RSADeleter> key(RSA_new());
-    if (!key) {
-      return nullptr;
-    }
-
-    key->n = BN_bin2bn((uint8_t*)modulus.get(),
-                       key_len_words * sizeof(uint32_t), NULL);
-    if (!key->n) {
-      return nullptr;
-    }
-
-    key->e = BN_new();
-    if (!key->e || !BN_set_word(key->e, exponent)) {
-      return nullptr;
-    }
-
-    return key;
-}
-
-struct BNDeleter {
-  void operator()(BIGNUM* bn) const {
-    BN_free(bn);
-  }
-};
-
-std::unique_ptr<EC_KEY, ECKEYDeleter> parse_ec_key(FILE* file) {
-    uint32_t key_len_bytes = 0;
-    if (fscanf(file, " %i", &key_len_bytes) != 1) {
-        return nullptr;
-    }
-
-    std::unique_ptr<EC_GROUP, void (*)(EC_GROUP*)> group(
-        EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1), EC_GROUP_free);
-    if (!group) {
-        return nullptr;
-    }
-
-    // Verify that |key_len| matches the group order.
-    if (key_len_bytes != BN_num_bytes(EC_GROUP_get0_order(group.get()))) {
-        return nullptr;
-    }
-
-    // Read the public key coordinates. Note that the byte order in the file is
-    // little-endian, so we convert to big-endian here.
-    std::unique_ptr<uint8_t[]> bytes(new uint8_t[key_len_bytes]);
-    std::unique_ptr<BIGNUM, BNDeleter> point[2];
-    for (int i = 0; i < 2; ++i) {
-        unsigned int byte = 0;
-        if (fscanf(file, " , { %u", &byte) != 1) {
-            return nullptr;
-        }
-        bytes[key_len_bytes - 1] = byte;
-
-        for (size_t i = 1; i < key_len_bytes; ++i) {
-            if (fscanf(file, " , %u", &byte) != 1) {
-                return nullptr;
-            }
-            bytes[key_len_bytes - i - 1] = byte;
-        }
-
-        point[i].reset(BN_bin2bn(bytes.get(), key_len_bytes, nullptr));
-        if (!point[i]) {
-            return nullptr;
-        }
-
-        if (fscanf(file, " }") != 0) {
-            return nullptr;
-        }
-    }
-
-    if (fscanf(file, " } ") != 0) {
-        return nullptr;
-    }
-
-    // Create and initialize the key.
-    std::unique_ptr<EC_KEY, ECKEYDeleter> key(EC_KEY_new());
-    if (!key || !EC_KEY_set_group(key.get(), group.get()) ||
-        !EC_KEY_set_public_key_affine_coordinates(key.get(), point[0].get(),
-                                                  point[1].get())) {
-        return nullptr;
-    }
-
-    return key;
-}
-
 static std::vector<Certificate> IterateZipEntriesAndSearchForKeys(const ZipArchiveHandle& handle) {
   void* cookie;
   ZipString suffix("x509.pem");
@@ -500,6 +362,48 @@
   return result;
 }
 
+bool CheckRSAKey(const std::unique_ptr<RSA, RSADeleter>& rsa) {
+  if (!rsa) {
+    return false;
+  }
+
+  const BIGNUM* out_n;
+  const BIGNUM* out_e;
+  RSA_get0_key(rsa.get(), &out_n, &out_e, nullptr /* private exponent */);
+  auto modulus_bits = BN_num_bits(out_n);
+  if (modulus_bits != 2048) {
+    LOG(ERROR) << "Modulus should be 2048 bits long, actual: " << modulus_bits;
+    return false;
+  }
+
+  BN_ULONG exponent = BN_get_word(out_e);
+  if (exponent != 3 && exponent != 65537) {
+    LOG(ERROR) << "Public exponent should be 3 or 65537, actual: " << exponent;
+    return false;
+  }
+
+  return true;
+}
+
+bool CheckECKey(const std::unique_ptr<EC_KEY, ECKEYDeleter>& ec_key) {
+  if (!ec_key) {
+    return false;
+  }
+
+  const EC_GROUP* ec_group = EC_KEY_get0_group(ec_key.get());
+  if (!ec_group) {
+    LOG(ERROR) << "Failed to get the ec_group from the ec_key";
+    return false;
+  }
+  auto degree = EC_GROUP_get_degree(ec_group);
+  if (degree != 256) {
+    LOG(ERROR) << "Field size of the ec key should be 256 bits long, actual: " << degree;
+    return false;
+  }
+
+  return true;
+}
+
 bool LoadCertificateFromBuffer(const std::vector<uint8_t>& pem_content, Certificate* cert) {
   std::unique_ptr<BIO, decltype(&BIO_free)> content(
       BIO_new_mem_buf(pem_content.data(), pem_content.size()), BIO_free);
@@ -538,22 +442,20 @@
   }
 
   int key_type = EVP_PKEY_id(public_key.get());
-  // TODO(xunchang) check the rsa key has exponent 3 or 65537 with RSA_get0_key; and ec key is
-  // 256 bits.
   if (key_type == EVP_PKEY_RSA) {
     cert->key_type = Certificate::KEY_TYPE_RSA;
     cert->ec.reset();
     cert->rsa.reset(EVP_PKEY_get1_RSA(public_key.get()));
-    if (!cert->rsa) {
-      LOG(ERROR) << "Failed to get the rsa key info from public key";
+    if (!cert->rsa || !CheckRSAKey(cert->rsa)) {
+      LOG(ERROR) << "Failed to validate the rsa key info from public key";
       return false;
     }
   } else if (key_type == EVP_PKEY_EC) {
     cert->key_type = Certificate::KEY_TYPE_EC;
     cert->rsa.reset();
     cert->ec.reset(EVP_PKEY_get1_EC_KEY(public_key.get()));
-    if (!cert->ec) {
-      LOG(ERROR) << "Failed to get the ec key info from the public key";
+    if (!cert->ec || !CheckECKey(cert->ec)) {
+      LOG(ERROR) << "Failed to validate the ec key info from the public key";
       return false;
     }
   } else {
@@ -563,114 +465,3 @@
 
   return true;
 }
-
-// Reads a file containing one or more public keys as produced by
-// DumpPublicKey:  this is an RSAPublicKey struct as it would appear
-// as a C source literal, eg:
-//
-//  "{64,0xc926ad21,{1795090719,...,-695002876},{-857949815,...,1175080310}}"
-//
-// For key versions newer than the original 2048-bit e=3 keys
-// supported by Android, the string is preceded by a version
-// identifier, eg:
-//
-//  "v2 {64,0xc926ad21,{1795090719,...,-695002876},{-857949815,...,1175080310}}"
-//
-// (Note that the braces and commas in this example are actual
-// characters the parser expects to find in the file; the ellipses
-// indicate more numbers omitted from this example.)
-//
-// The file may contain multiple keys in this format, separated by
-// commas.  The last key must not be followed by a comma.
-//
-// A Certificate is a pair of an RSAPublicKey and a particular hash
-// (we support SHA-1 and SHA-256; we store the hash length to signify
-// which is being used).  The hash used is implied by the version number.
-//
-//       1: 2048-bit RSA key with e=3 and SHA-1 hash
-//       2: 2048-bit RSA key with e=65537 and SHA-1 hash
-//       3: 2048-bit RSA key with e=3 and SHA-256 hash
-//       4: 2048-bit RSA key with e=65537 and SHA-256 hash
-//       5: 256-bit EC key using the NIST P-256 curve parameters and SHA-256 hash
-//
-// Returns true on success, and appends the found keys (at least one) to certs.
-// Otherwise returns false if the file failed to parse, or if it contains zero
-// keys. The contents in certs would be unspecified on failure.
-bool load_keys(const char* filename, std::vector<Certificate>& certs) {
-  std::unique_ptr<FILE, decltype(&fclose)> f(fopen(filename, "re"), fclose);
-  if (!f) {
-    PLOG(ERROR) << "error opening " << filename;
-    return false;
-  }
-
-  while (true) {
-    certs.emplace_back(0, Certificate::KEY_TYPE_RSA, nullptr, nullptr);
-    Certificate& cert = certs.back();
-    uint32_t exponent = 0;
-
-    char start_char;
-    if (fscanf(f.get(), " %c", &start_char) != 1) return false;
-    if (start_char == '{') {
-      // a version 1 key has no version specifier.
-      cert.key_type = Certificate::KEY_TYPE_RSA;
-      exponent = 3;
-      cert.hash_len = SHA_DIGEST_LENGTH;
-    } else if (start_char == 'v') {
-      int version;
-      if (fscanf(f.get(), "%d {", &version) != 1) return false;
-      switch (version) {
-        case 2:
-          cert.key_type = Certificate::KEY_TYPE_RSA;
-          exponent = 65537;
-          cert.hash_len = SHA_DIGEST_LENGTH;
-          break;
-        case 3:
-          cert.key_type = Certificate::KEY_TYPE_RSA;
-          exponent = 3;
-          cert.hash_len = SHA256_DIGEST_LENGTH;
-          break;
-        case 4:
-          cert.key_type = Certificate::KEY_TYPE_RSA;
-          exponent = 65537;
-          cert.hash_len = SHA256_DIGEST_LENGTH;
-          break;
-        case 5:
-          cert.key_type = Certificate::KEY_TYPE_EC;
-          cert.hash_len = SHA256_DIGEST_LENGTH;
-          break;
-        default:
-          return false;
-      }
-    }
-
-    if (cert.key_type == Certificate::KEY_TYPE_RSA) {
-      cert.rsa = parse_rsa_key(f.get(), exponent);
-      if (!cert.rsa) {
-        return false;
-      }
-
-      LOG(INFO) << "read key e=" << exponent << " hash=" << cert.hash_len;
-    } else if (cert.key_type == Certificate::KEY_TYPE_EC) {
-      cert.ec = parse_ec_key(f.get());
-      if (!cert.ec) {
-        return false;
-      }
-    } else {
-      LOG(ERROR) << "Unknown key type " << cert.key_type;
-      return false;
-    }
-
-    // if the line ends in a comma, this file has more keys.
-    int ch = fgetc(f.get());
-    if (ch == ',') {
-      // more keys to come.
-      continue;
-    } else if (ch == EOF) {
-      break;
-    } else {
-      LOG(ERROR) << "unexpected character between keys";
-      return false;
-    }
-  }
-  return true;
-}
diff --git a/verifier.h b/verifier.h
index b7924c7..df9a4b6 100644
--- a/verifier.h
+++ b/verifier.h
@@ -70,7 +70,11 @@
 int verify_file(const unsigned char* addr, size_t length, const std::vector<Certificate>& keys,
                 const std::function<void(float)>& set_progress = nullptr);
 
-bool load_keys(const char* filename, std::vector<Certificate>& certs);
+// Checks that the RSA key has a modulus of 2048 bits long, and public exponent is 3 or 65537.
+bool CheckRSAKey(const std::unique_ptr<RSA, RSADeleter>& rsa);
+
+// Checks that the field size of the curve for the EC key is 256 bits.
+bool CheckECKey(const std::unique_ptr<EC_KEY, ECKEYDeleter>& ec_key);
 
 // Parses a PEM-encoded x509 certificate from the given buffer and saves it into |cert|. Returns
 // false if there is a parsing failure or the signature's encryption algorithm is not supported.