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(Unicode C) ECDSA Sign Data and Verify SignatureDemonstrates using the Elliptic Curve Digital Signature Algorithm to hash data and sign it. Also demonstrates how to verify the ECDSA signature.
#include <C_CkCrypt2W.h> #include <C_CkPrivateKeyW.h> #include <C_CkPrngW.h> #include <C_CkEccW.h> #include <C_CkPublicKeyW.h> void ChilkatSample(void) { HCkCrypt2W crypt; const wchar_t *hash1; const wchar_t *hash2; HCkPrivateKeyW privKey; BOOL success; HCkPrngW prng; HCkEccW ecdsa; const wchar_t *ecdsaSigBase64; HCkPublicKeyW pubKey; int result; // This example requires the Chilkat API to have been previously unlocked. // See Global Unlock Sample for sample code. // To create an ECDSA signature, the data first needs to be hashed. Then the hash // is signed. // Use Chilkat Crypt2 to generate a hash for any of the following // hash algorithms: SHA256, SHA384, SHA512, SHA1, MD5, MD2, HAVAL, RIPEMD128/160/256/320 crypt = CkCrypt2W_Create(); CkCrypt2W_putHashAlgorithm(crypt,L"SHA256"); CkCrypt2W_putCharset(crypt,L"utf-8"); CkCrypt2W_putEncodingMode(crypt,L"base64"); // Hash a string. hash1 = CkCrypt2W_hashStringENC(crypt,L"The quick brown fox jumps over the lazy dog"); wprintf(L"hash1 = %s\n",hash1); // Or hash a file.. hash2 = CkCrypt2W_hashFileENC(crypt,L"qa_data/hamlet.xml"); wprintf(L"hash2 = %s\n",hash2); // (The Crypt2 API provides many other ways to hash data..) // ----------------------------------------------------------- // An ECDSA private key is used for signing. The public key is for signature verification. // Load our ECC private key. // Our private key file contains this: // // -----BEGIN PRIVATE KEY----- // MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQg3J8q/24D1sEKGdP9 // 72MGYElLGpw/a56Y3t6pfON3uhShRANCAATlSmoizyhAwoYZAOuFBATl07/1RR54 // a1Dzfm16grxJe666AGKR+bSs24hk7TEpaeCTvT8YOOM3l+xKFg7zq6Q9 // -----END PRIVATE KEY----- privKey = CkPrivateKeyW_Create(); success = CkPrivateKeyW_LoadPemFile(privKey,L"qa_data/ecc/secp256r1-key-pkcs8.pem"); if (success != TRUE) { wprintf(L"%s\n",CkPrivateKeyW_lastErrorText(privKey)); CkCrypt2W_Dispose(crypt); CkPrivateKeyW_Dispose(privKey); return; } // We'll need a PRNG source for random number generation. // Use Chilkat's PRNG (for the Fortuna PRNG algorithm). prng = CkPrngW_Create(); // Sign the hash.. ecdsa = CkEccW_Create(); ecdsaSigBase64 = CkEccW_signHashENC(ecdsa,hash1,L"base64",privKey,prng); if (CkEccW_getLastMethodSuccess(ecdsa) != TRUE) { wprintf(L"%s\n",CkEccW_lastErrorText(ecdsa)); CkCrypt2W_Dispose(crypt); CkPrivateKeyW_Dispose(privKey); CkPrngW_Dispose(prng); CkEccW_Dispose(ecdsa); return; } wprintf(L"ECDSA signature = %s\n",ecdsaSigBase64); // ----------------------------------------------------------- // Now let's verify the signature using the public key. pubKey = CkPublicKeyW_Create(); success = CkPublicKeyW_LoadFromFile(pubKey,L"qa_data/ecc/secp256r1-pubkey.pem"); if (success != TRUE) { wprintf(L"%s\n",CkPublicKeyW_lastErrorText(pubKey)); CkCrypt2W_Dispose(crypt); CkPrivateKeyW_Dispose(privKey); CkPrngW_Dispose(prng); CkEccW_Dispose(ecdsa); CkPublicKeyW_Dispose(pubKey); return; } result = CkEccW_VerifyHashENC(ecdsa,hash1,ecdsaSigBase64,L"base64",pubKey); if (result == 1) { wprintf(L"Signature is valid.\n"); CkCrypt2W_Dispose(crypt); CkPrivateKeyW_Dispose(privKey); CkPrngW_Dispose(prng); CkEccW_Dispose(ecdsa); CkPublicKeyW_Dispose(pubKey); return; } if (result == 0) { wprintf(L"Signature is invalid.\n"); CkCrypt2W_Dispose(crypt); CkPrivateKeyW_Dispose(privKey); CkPrngW_Dispose(prng); CkEccW_Dispose(ecdsa); CkPublicKeyW_Dispose(pubKey); return; } if (result < 0) { wprintf(L"%s\n",CkEccW_lastErrorText(ecdsa)); wprintf(L"The VerifyHashENC method call failed.\n"); CkCrypt2W_Dispose(crypt); CkPrivateKeyW_Dispose(privKey); CkPrngW_Dispose(prng); CkEccW_Dispose(ecdsa); CkPublicKeyW_Dispose(pubKey); return; } CkCrypt2W_Dispose(crypt); CkPrivateKeyW_Dispose(privKey); CkPrngW_Dispose(prng); CkEccW_Dispose(ecdsa); CkPublicKeyW_Dispose(pubKey); } |
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