diff --git a/crypto/ecdsa/ecdsa_test.cc b/crypto/ecdsa/ecdsa_test.cc
new file mode 100644
index 0000000..a6bd7a1
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+++ b/crypto/ecdsa/ecdsa_test.cc
@@ -0,0 +1,340 @@
+/* ====================================================================
+ * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ *    software must display the following acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@OpenSSL.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com).  This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com). */
+
+#include <openssl/ecdsa.h>
+
+#include <vector>
+
+#include <openssl/bn.h>
+#include <openssl/crypto.h>
+#include <openssl/ec.h>
+#include <openssl/err.h>
+#include <openssl/mem.h>
+#include <openssl/obj.h>
+#include <openssl/rand.h>
+
+#include "../test/scoped_types.h"
+#include "../test/stl_compat.h"
+
+enum Api {
+  kEncodedApi,
+  kRawApi,
+};
+
+// VerifyECDSASig returns true on success, false on failure.
+static bool VerifyECDSASig(Api api, const uint8_t *digest,
+                           size_t digest_len, const ECDSA_SIG *ecdsa_sig,
+                           EC_KEY *eckey, int expected_result) {
+  int actual_result;
+
+  switch (api) {
+    case kEncodedApi: {
+      int sig_len = i2d_ECDSA_SIG(ecdsa_sig, NULL);
+      if (sig_len <= 0) {
+        return false;
+      }
+      std::vector<uint8_t> signature(static_cast<size_t>(sig_len));
+      uint8_t *sig_ptr = bssl::vector_data(&signature);
+      sig_len = i2d_ECDSA_SIG(ecdsa_sig, &sig_ptr);
+      if (sig_len <= 0) {
+        return false;
+      }
+      actual_result = ECDSA_verify(0, digest, digest_len, bssl::vector_data(&signature),
+                                   signature.size(), eckey);
+      break;
+    }
+
+    case kRawApi:
+      actual_result = ECDSA_do_verify(digest, digest_len, ecdsa_sig, eckey);
+      break;
+
+    default:
+      return false;
+  }
+  return expected_result == actual_result;
+}
+
+// TestTamperedSig verifies that signature verification fails when a valid
+// signature is tampered with. |ecdsa_sig| must be a valid signature, which will
+// be modified. TestTamperedSig returns true on success, false on failure.
+static bool TestTamperedSig(FILE *out, Api api, const uint8_t *digest,
+                            size_t digest_len, ECDSA_SIG *ecdsa_sig,
+                            EC_KEY *eckey, const BIGNUM *order) {
+  // Modify a single byte of the signature: to ensure we don't
+  // garble the ASN1 structure, we read the raw signature and
+  // modify a byte in one of the bignums directly.
+
+  // Store the two BIGNUMs in raw_buf.
+  size_t r_len = BN_num_bytes(ecdsa_sig->r);
+  size_t s_len = BN_num_bytes(ecdsa_sig->s);
+  size_t bn_len = BN_num_bytes(order);
+  if (r_len > bn_len || s_len > bn_len) {
+    return false;
+  }
+  size_t buf_len = 2 * bn_len;
+  std::vector<uint8_t> raw_buf(buf_len);
+  // Pad the bignums with leading zeroes.
+  if (!BN_bn2bin_padded(bssl::vector_data(&raw_buf), bn_len, ecdsa_sig->r) ||
+      !BN_bn2bin_padded(bssl::vector_data(&raw_buf) + bn_len, bn_len,
+                        ecdsa_sig->s)) {
+    return false;
+  }
+
+  // Modify a single byte in the buffer.
+  size_t offset = raw_buf[10] % buf_len;
+  uint8_t dirt = raw_buf[11] ? raw_buf[11] : 1;
+  raw_buf[offset] ^= dirt;
+  // Now read the BIGNUMs back in from raw_buf.
+  if (BN_bin2bn(bssl::vector_data(&raw_buf), bn_len, ecdsa_sig->r) == NULL ||
+      BN_bin2bn(bssl::vector_data(&raw_buf) + bn_len, bn_len,
+                ecdsa_sig->s) == NULL ||
+      !VerifyECDSASig(api, digest, digest_len, ecdsa_sig, eckey, 0)) {
+    return false;
+  }
+
+  // Sanity check: Undo the modification and verify signature.
+  raw_buf[offset] ^= dirt;
+  if (BN_bin2bn(bssl::vector_data(&raw_buf), bn_len, ecdsa_sig->r) == NULL ||
+      BN_bin2bn(bssl::vector_data(&raw_buf) + bn_len, bn_len,
+                ecdsa_sig->s) == NULL ||
+      !VerifyECDSASig(api, digest, digest_len, ecdsa_sig, eckey, 1)) {
+    return false;
+  }
+
+  return true;
+}
+
+static bool TestBuiltin(FILE *out) {
+  // Fill digest values with some random data.
+  uint8_t digest[20], wrong_digest[20];
+  if (!RAND_bytes(digest, 20) || !RAND_bytes(wrong_digest, 20)) {
+    fprintf(out, "ERROR: unable to get random data\n");
+    return false;
+  }
+
+  static const struct {
+    int nid;
+    const char *name;
+  } kCurves[] = {
+      { NID_secp224r1, "secp224r1" },
+      { NID_X9_62_prime256v1, "secp256r1" },
+      { NID_secp384r1, "secp384r1" },
+      { NID_secp521r1, "secp521r1" },
+      { NID_undef, NULL }
+  };
+
+  // Create and verify ECDSA signatures with every available curve.
+  fputs("\ntesting ECDSA_sign(), ECDSA_verify(), ECDSA_do_sign(), and "
+        "ECDSA_do_verify() with some internal curves:\n", out);
+
+  for (size_t n = 0; kCurves[n].nid != NID_undef; n++) {
+    fprintf(out, "%s: ", kCurves[n].name);
+
+    int nid = kCurves[n].nid;
+    ScopedEC_GROUP group(EC_GROUP_new_by_curve_name(nid));
+    if (!group) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    ScopedBIGNUM order(BN_new());
+    if (!order || !EC_GROUP_get_order(group.get(), order.get(), NULL)) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    if (BN_num_bits(order.get()) < 160) {
+      // Too small to test.
+      fprintf(out, " skipped\n");
+      continue;
+    }
+
+    // Create a new ECDSA key.
+    ScopedEC_KEY eckey(EC_KEY_new());
+    if (!eckey || !EC_KEY_set_group(eckey.get(), group.get()) ||
+        !EC_KEY_generate_key(eckey.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    // Create a second key.
+    ScopedEC_KEY wrong_eckey(EC_KEY_new());
+    if (!wrong_eckey || !EC_KEY_set_group(wrong_eckey.get(), group.get()) ||
+        !EC_KEY_generate_key(wrong_eckey.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+
+    fprintf(out, ".");
+    fflush(out);
+
+    // Check the key.
+    if (!EC_KEY_check_key(eckey.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    fprintf(out, ".");
+    fflush(out);
+
+    // Test ASN.1-encoded signatures.
+    // Create a signature.
+    unsigned sig_len = ECDSA_size(eckey.get());
+    std::vector<uint8_t> signature(sig_len);
+    if (!ECDSA_sign(0, digest, 20, bssl::vector_data(&signature), &sig_len,
+                    eckey.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    signature.resize(sig_len);
+    fprintf(out, ".");
+    fflush(out);
+    // Verify the signature.
+    if (!ECDSA_verify(0, digest, 20, bssl::vector_data(&signature),
+                      signature.size(), eckey.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    fprintf(out, ".");
+    fflush(out);
+    // Verify the signature with the wrong key.
+    if (ECDSA_verify(0, digest, 20, bssl::vector_data(&signature),
+                     signature.size(), wrong_eckey.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    fprintf(out, ".");
+    fflush(out);
+    // Verify the signature using the wrong digest.
+    if (ECDSA_verify(0, wrong_digest, 20, bssl::vector_data(&signature),
+                      signature.size(), eckey.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    fprintf(out, ".");
+    fflush(out);
+    // Verify a truncated signature.
+    if (ECDSA_verify(0, digest, 20, bssl::vector_data(&signature),
+                      signature.size() - 1, eckey.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    fprintf(out, ".");
+    fflush(out);
+    // Verify a tampered signature.
+    const uint8_t *sig_ptr = bssl::vector_data(&signature);
+    ScopedECDSA_SIG ecdsa_sig(d2i_ECDSA_SIG(NULL, &sig_ptr, signature.size()));
+    if (!ecdsa_sig ||
+        !TestTamperedSig(out, kEncodedApi, digest, 20, ecdsa_sig.get(),
+                         eckey.get(), order.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    fprintf(out, ".");
+    fflush(out);
+
+    // Test ECDSA_SIG signing and verification.
+    // Create a signature.
+    ecdsa_sig.reset(ECDSA_do_sign(digest, 20, eckey.get()));
+    if (!ecdsa_sig) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    fprintf(out, ".");
+    fflush(out);
+    // Verify the signature using the correct key.
+    if (!ECDSA_do_verify(digest, 20, ecdsa_sig.get(), eckey.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    fprintf(out, ".");
+    fflush(out);
+    // Verify the signature with the wrong key.
+    if (ECDSA_do_verify(digest, 20, ecdsa_sig.get(), wrong_eckey.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    fprintf(out, ".");
+    fflush(out);
+    // Verify the signature using the wrong digest.
+    if (ECDSA_do_verify(wrong_digest, 20, ecdsa_sig.get(), eckey.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    fprintf(out, ".");
+    fflush(out);
+    // Verify a tampered signature.
+    if (!TestTamperedSig(out, kRawApi, digest, 20, ecdsa_sig.get(), eckey.get(),
+                         order.get())) {
+      fprintf(out, " failed\n");
+      return false;
+    }
+    fprintf(out, ".");
+    fflush(out);
+
+    fprintf(out, " ok\n");
+    // Clear bogus errors.
+    ERR_clear_error();
+  }
+
+  return true;
+}
+
+int main(void) {
+  CRYPTO_library_init();
+  ERR_load_crypto_strings();
+
+  if (!TestBuiltin(stdout)) {
+    printf("\nECDSA test failed\n");
+    ERR_print_errors_fp(stdout);
+    return 1;
+  }
+
+  printf("\nPASS\n");
+  return 0;
+}