Delphi DLL Requires Chilkat v9.5.0.85+

ECDSA Sign and Verify Data using Different Hash Algorithms

See more ECC Examples

Demonstrates how to create ECDSA signatures on data using different hash algorithms. Delphi DLL

var
success: Boolean;
privKey: HCkPrivateKey;
bd: HCkBinData;
ecdsa: HCkEcc;
prng: HCkPrng;
sig: PWideChar;
pubKey: HCkPublicKey;
ecc2: HCkEcc;
result: Integer;

begin
success := False;

//  This example assumes the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

//  First load an ECDSA private key to be used for signing.
privKey := CkPrivateKey_Create();
success := CkPrivateKey_LoadEncryptedPemFile(privKey,'qa_data/ecc/secp256r1-key-pkcs8-secret.pem','secret');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPrivateKey__lastErrorText(privKey));
    Exit;
  end;

//  Load some data to be signed.
bd := CkBinData_Create();
success := CkBinData_LoadFile(bd,'qa_data/hamlet.xml');
if (success = False) then
  begin
    Memo1.Lines.Add('Failed to load file to be hashed.');
    Exit;
  end;

ecdsa := CkEcc_Create();
prng := CkPrng_Create();

//  Sign the sha256 hash of the data.  Return the ECDSA signature in the base64 encoding.
Memo1.Lines.Add('ECDSA signing the sha256 hash of the data...');
sig := CkEcc__signBd(ecdsa,bd,'sha256','base64',privKey,prng);
Memo1.Lines.Add('sig = ' + sig);

//  Verify the signature against the original data.
//  (We must use the same hash algorithm that was used when signing.)

//  Load the public key that corresponds to the private key used for signing.
pubKey := CkPublicKey_Create();
success := CkPublicKey_LoadFromFile(pubKey,'qa_data/ecc/secp256r1-pub.pem');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPublicKey__lastErrorText(pubKey));
    Exit;
  end;

ecc2 := CkEcc_Create();
result := CkEcc_VerifyBd(ecc2,bd,'sha256',sig,'base64',pubKey);
if (result <> 1) then
  begin
    Memo1.Lines.Add(CkEcc__lastErrorText(ecc2));
    Exit;
  end;

Memo1.Lines.Add('Verified!');

//  ----------------------------------------------------------------------------------------
//  Let's do the same thing, but with sha384 hashing...

Memo1.Lines.Add('--------------------------------------------');
Memo1.Lines.Add('ECDSA signing the sha384 hash of the data...');

sig := CkEcc__signBd(ecdsa,bd,'sha384','base64',privKey,prng);
Memo1.Lines.Add('sig = ' + sig);

result := CkEcc_VerifyBd(ecc2,bd,'sha384',sig,'base64',pubKey);
if (result <> 1) then
  begin
    Memo1.Lines.Add(CkEcc__lastErrorText(ecc2));
    Exit;
  end;

Memo1.Lines.Add('Verified!');

CkPrivateKey_Dispose(privKey);
CkBinData_Dispose(bd);
CkEcc_Dispose(ecdsa);
CkPrng_Dispose(prng);
CkPublicKey_Dispose(pubKey);
CkEcc_Dispose(ecc2);