Re: [openssl-users] OpenSSL occasionally generates wrong signature

2018-10-16 Thread Dmitry 
Looks like there is some problem in higher-level EVP_ functions.

I completely rewrote the example using lower-level ECDSA_do_sign and it
started to work always.

Here is the code:
   EVP_MD_CTX *Ctx = EVP_MD_CTX_create();
   EVP_DigestInit(Ctx, EVP_sha256());
   EVP_DigestUpdate(Ctx, dt.data(), dt.size());
   QByteArray Digest;
   Digest.resize(EVP_MAX_MD_SIZE);
   unsigned int Len;
   EVP_DigestFinal(Ctx, reinterpret_cast(Digest.data()),
&Len);
   Digest.resize(Len);

   BIO *   Bio   = BIO_new_mem_buf(pk.data(), pk.size());
   EC_KEY *ECKey = PEM_read_bio_ECPrivateKey(Bio, nullptr, nullptr,
nullptr);
   ECDSA_SIG *Signature = ECDSA_do_sign(reinterpret_cast(Digest.data()), Digest.size(), ECKey);
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Re: [openssl-users] OpenSSL occasionally generates wrong signature

2018-10-16 Thread Dmitry 
Thank you for the hint, but it looks like the problem is somewhere else

I rewrote the piece of code in such a way:
char *Result = new char [SignatureLength];
EVP_DigestSignFinal(Ctx, reinterpret_cast(Result),
&SignatureLength);

TFile SignatureBin = {"/home/gc/signature.bin", ...};
SignatureBin.Write(Result, SignatureLength);

but the problem still persists.
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Re: [openssl-users] OpenSSL occasionally generates wrong signature

2018-10-16 Thread Jakob Bohm via openssl-users 

On 16/10/2018 16:39, Dmitry wrote:

Hello!

I have a C++ programme, ECDSA key pair and some string to sign. The 
programme generates signature and saves it into a file 
(signature.bin). Then I check the validity of the signature via the 
following command:


openssl dgst -verify ec_public.pem -signature signature.bin ToSign.txt

the problem is that *my programme sometimes generates wrong 
signature*. 16 times out of 21 the signature produced is invalid and 
the above command outputs:

Error Verifying Data

while in the remaining 5 occurrences it outputs:
Verified OK

Do you have any ideas of how it can be possible? What am I doing wrong?


Here is the programme:

SSL_library_init();
OPENSSL_config(nullptr);
SSL_load_error_strings();
OpenSSL_add_all_algorithms();
ERR_load_BIO_strings();
CRYPTO_set_id_callback(ThreadIdFunction);
CRYPTO_set_locking_callback(LockingFunction);

const TString pk = "-BEGIN EC PRIVATE KEY-\n"
 "MHcCAQEEIG90zmo1o3NWNFa8wp2z4rdQXGSN8xAP/OATLpwlgi+1oAoGCCqGSM49\n"
 "AwEHoUQDQgAE5TwpzBhjUWZoOf629GfwGG5WlRJD7TSuz+ZTHUaiK5mj2qgxBOPk\n"
 "eqOrTYXsiPwnaWe23zHjIM8NOhAm1BiGgA==\n"
                     "-END EC PRIVATE KEY-\n";

const TString ToSign = 
"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJhdWQiOiJhc2RmIn0";


EVP_MD_CTX *Ctx    = EVP_MD_CTX_create();
BIO *       Bio    = BIO_new_mem_buf(pk.data(), pk.size());
EVP_PKEY *  EVPKey = PEM_read_bio_PrivateKey(Bio, nullptr, nullptr, 
nullptr);


EVP_DigestSignInit(Ctx, nullptr, EVP_sha256(), nullptr, EVPKey);
EVP_DigestSignUpdate(Ctx, ToSign.data(), ToSign.size());
size_t SignatureLength;
EVP_DigestSignFinal(Ctx, nullptr, &SignatureLength);

TString Result;

^^^ You are treating binary data as a string.
Chances are the TString class will truncate at the first byte with
the value zero, and/or do some other text-specific thing that is bad
for binary data.


Result.resize(SignatureLength);
EVP_DigestSignFinal(Ctx, reinterpret_cast*>(const_cast(Result.data())), &SignatureLength);


// Saving to file...



Enjoy

Jakob
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Transformervej 29, 2860 Søborg, Denmark.  Direct +45 31 13 16 10
This public discussion message is non-binding and may contain errors.
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[openssl-users] OpenSSL occasionally generates wrong signature

2018-10-16 Thread Dmitry 
Hello!

I have a C++ programme, ECDSA key pair and some string to sign. The
programme generates signature and saves it into a file (signature.bin).
Then I check the validity of the signature via the following command:

openssl dgst -verify ec_public.pem -signature signature.bin ToSign.txt

the problem is that *my programme sometimes generates wrong signature*. 16
times out of 21 the signature produced is invalid and the above command
outputs:
Error Verifying Data

while in the remaining 5 occurrences it outputs:
Verified OK

Do you have any ideas of how it can be possible? What am I doing wrong?


Here is the programme:

SSL_library_init();
OPENSSL_config(nullptr);
SSL_load_error_strings();
OpenSSL_add_all_algorithms();
ERR_load_BIO_strings();
CRYPTO_set_id_callback(ThreadIdFunction);
CRYPTO_set_locking_callback(LockingFunction);

const TString pk = "-BEGIN EC PRIVATE KEY-\n"

 "MHcCAQEEIG90zmo1o3NWNFa8wp2z4rdQXGSN8xAP/OATLpwlgi+1oAoGCCqGSM49\n"

 "AwEHoUQDQgAE5TwpzBhjUWZoOf629GfwGG5WlRJD7TSuz+ZTHUaiK5mj2qgxBOPk\n"
   "eqOrTYXsiPwnaWe23zHjIM8NOhAm1BiGgA==\n"
   "-END EC PRIVATE KEY-\n";

const TString ToSign =
"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJhdWQiOiJhc2RmIn0";

EVP_MD_CTX *Ctx= EVP_MD_CTX_create();
BIO *   Bio= BIO_new_mem_buf(pk.data(), pk.size());
EVP_PKEY *  EVPKey = PEM_read_bio_PrivateKey(Bio, nullptr, nullptr,
nullptr);

EVP_DigestSignInit(Ctx, nullptr, EVP_sha256(), nullptr, EVPKey);
EVP_DigestSignUpdate(Ctx, ToSign.data(), ToSign.size());
size_t SignatureLength;
EVP_DigestSignFinal(Ctx, nullptr, &SignatureLength);

TString Result;
Result.resize(SignatureLength);
EVP_DigestSignFinal(Ctx, reinterpret_cast(const_cast(Result.data())), &SignatureLength);

// Saving to file...

Thank you in advance
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