crypto/ecdsa/ecdsa_test.cc - boringssl - Git at Google

 /* ====================================================================
  * 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/nid.h>
 #include <openssl/rand.h>

 #include "../test/scoped_types.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: {
       uint8_t *der;
       size_t der_len;
       if (!ECDSA_SIG_to_bytes(&der, &der_len, ecdsa_sig)) {
         return false;
       }
       ScopedOpenSSLBytes delete_der(der);
       actual_result = ECDSA_verify(0, digest, digest_len, der, der_len, 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(raw_buf.data(), bn_len, ecdsa_sig->r) ||
       !BN_bn2bin_padded(raw_buf.data() + 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(raw_buf.data(), bn_len, ecdsa_sig->r) == NULL ||
       BN_bin2bn(raw_buf.data() + 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(raw_buf.data(), bn_len, ecdsa_sig->r) == NULL ||
       BN_bin2bn(raw_buf.data() + 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;
     }
     const BIGNUM *order = EC_GROUP_get0_order(group.get());
     if (BN_num_bits(order) < 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, signature.data(), &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, signature.data(), 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, signature.data(), 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, signature.data(), signature.size(),
                      eckey.get())) {
       fprintf(out, " failed\n");
       return false;
     }
     fprintf(out, ".");
     fflush(out);
     // Verify a truncated signature.
     if (ECDSA_verify(0, digest, 20, signature.data(), signature.size() - 1,
                      eckey.get())) {
       fprintf(out, " failed\n");
       return false;
     }
     fprintf(out, ".");
     fflush(out);
     // Verify a tampered signature.
     ScopedECDSA_SIG ecdsa_sig(ECDSA_SIG_from_bytes(
         signature.data(), signature.size()));
     if (!ecdsa_sig ||
         !TestTamperedSig(out, kEncodedApi, digest, 20, ecdsa_sig.get(),
                          eckey.get(), order)) {
       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)) {
       fprintf(out, " failed\n");
       return false;
     }
     fprintf(out, ".");
     fflush(out);

     fprintf(out, " ok\n");
     // Clear bogus errors.
     ERR_clear_error();
   }

   return true;
 }

 static bool TestECDSA_SIG_max_len(size_t order_len) {
   /* Create the largest possible |ECDSA_SIG| of the given constraints. */
   ScopedECDSA_SIG sig(ECDSA_SIG_new());
   if (!sig) {
     return false;
   }
   std::vector<uint8_t> bytes(order_len, 0xff);
   if (!BN_bin2bn(bytes.data(), bytes.size(), sig->r) ||
       !BN_bin2bn(bytes.data(), bytes.size(), sig->s)) {
     return false;
   }
   /* Serialize it. */
   uint8_t *der;
   size_t der_len;
   if (!ECDSA_SIG_to_bytes(&der, &der_len, sig.get())) {
     return false;
   }
   ScopedOpenSSLBytes delete_der(der);

   size_t max_len = ECDSA_SIG_max_len(order_len);
   if (max_len != der_len) {
     fprintf(stderr, "ECDSA_SIG_max_len(%u) returned %u, wanted %u\n",
             static_cast<unsigned>(order_len), static_cast<unsigned>(max_len),
             static_cast<unsigned>(der_len));
     return false;
   }
   return true;
 }

 static size_t BitsToBytes(size_t bits) {
   return (bits / 8) + (7 + (bits % 8)) / 8;
 }

 int main(void) {
   CRYPTO_library_init();

   if (!TestBuiltin(stdout) ||
       !TestECDSA_SIG_max_len(BitsToBytes(224)) ||
       !TestECDSA_SIG_max_len(BitsToBytes(256)) ||
       !TestECDSA_SIG_max_len(BitsToBytes(384)) ||
       !TestECDSA_SIG_max_len(BitsToBytes(521)) ||
       !TestECDSA_SIG_max_len(BitsToBytes(10000))) {
     printf("\nECDSA test failed\n");
     ERR_print_errors_fp(stdout);
     return 1;
   }

   printf("\nPASS\n");
   return 0;
 }
	/* ====================================================================
	* 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/nid.h>
	#include <openssl/rand.h>

	#include "../test/scoped_types.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: {
	uint8_t *der;
	size_t der_len;
	if (!ECDSA_SIG_to_bytes(&der, &der_len, ecdsa_sig)) {
	return false;
	}
	ScopedOpenSSLBytes delete_der(der);
	actual_result = ECDSA_verify(0, digest, digest_len, der, der_len, 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(raw_buf.data(), bn_len, ecdsa_sig->r) \|\|
	!BN_bn2bin_padded(raw_buf.data() + 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(raw_buf.data(), bn_len, ecdsa_sig->r) == NULL \|\|
	BN_bin2bn(raw_buf.data() + 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(raw_buf.data(), bn_len, ecdsa_sig->r) == NULL \|\|
	BN_bin2bn(raw_buf.data() + 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;
	}
	const BIGNUM *order = EC_GROUP_get0_order(group.get());
	if (BN_num_bits(order) < 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, signature.data(), &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, signature.data(), 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, signature.data(), 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, signature.data(), signature.size(),
	eckey.get())) {
	fprintf(out, " failed\n");
	return false;
	}
	fprintf(out, ".");
	fflush(out);
	// Verify a truncated signature.
	if (ECDSA_verify(0, digest, 20, signature.data(), signature.size() - 1,
	eckey.get())) {
	fprintf(out, " failed\n");
	return false;
	}
	fprintf(out, ".");
	fflush(out);
	// Verify a tampered signature.
	ScopedECDSA_SIG ecdsa_sig(ECDSA_SIG_from_bytes(
	signature.data(), signature.size()));
	if (!ecdsa_sig \|\|
	!TestTamperedSig(out, kEncodedApi, digest, 20, ecdsa_sig.get(),
	eckey.get(), order)) {
	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)) {
	fprintf(out, " failed\n");
	return false;
	}
	fprintf(out, ".");
	fflush(out);

	fprintf(out, " ok\n");
	// Clear bogus errors.
	ERR_clear_error();
	}

	return true;
	}

	static bool TestECDSA_SIG_max_len(size_t order_len) {
	/* Create the largest possible \|ECDSA_SIG\| of the given constraints. */
	ScopedECDSA_SIG sig(ECDSA_SIG_new());
	if (!sig) {
	return false;
	}
	std::vector<uint8_t> bytes(order_len, 0xff);
	if (!BN_bin2bn(bytes.data(), bytes.size(), sig->r) \|\|
	!BN_bin2bn(bytes.data(), bytes.size(), sig->s)) {
	return false;
	}
	/* Serialize it. */
	uint8_t *der;
	size_t der_len;
	if (!ECDSA_SIG_to_bytes(&der, &der_len, sig.get())) {
	return false;
	}
	ScopedOpenSSLBytes delete_der(der);

	size_t max_len = ECDSA_SIG_max_len(order_len);
	if (max_len != der_len) {
	fprintf(stderr, "ECDSA_SIG_max_len(%u) returned %u, wanted %u\n",
	static_cast<unsigned>(order_len), static_cast<unsigned>(max_len),
	static_cast<unsigned>(der_len));
	return false;
	}
	return true;
	}

	static size_t BitsToBytes(size_t bits) {
	return (bits / 8) + (7 + (bits % 8)) / 8;
	}

	int main(void) {
	CRYPTO_library_init();

	if (!TestBuiltin(stdout) \|\|
	!TestECDSA_SIG_max_len(BitsToBytes(224)) \|\|
	!TestECDSA_SIG_max_len(BitsToBytes(256)) \|\|
	!TestECDSA_SIG_max_len(BitsToBytes(384)) \|\|
	!TestECDSA_SIG_max_len(BitsToBytes(521)) \|\|
	!TestECDSA_SIG_max_len(BitsToBytes(10000))) {
	printf("\nECDSA test failed\n");
	ERR_print_errors_fp(stdout);
	return 1;
	}

	printf("\nPASS\n");
	return 0;
	}