Modern cryptography for Delphi, in pure Object Pascal

uses
  sgcCrypto_Random, sgcCrypto_AES, sgcCrypto_Keccak;
var
  vKey, vIV, vPlain, vAAD, vTag, vCipher, vDigest: TBytes;
begin
  // AES-256-GCM: authenticated encryption in one call
  vKey    := sgcRandomBytes(32);
  vIV     := sgcRandomBytes(12);
  vPlain  := TEncoding.UTF8.GetBytes('confidential payload');
  vCipher := sgcAES_GCM_Encrypt(vKey, vIV, vPlain, vAAD, vTag);

  // SHA-3-256, one call, no context object to manage
  vDigest := sgcSHA3_256(vPlain);

  // Decryption checks the tag in constant time and fails closed
  vPlain  := sgcAES_GCM_Decrypt(vKey, vIV, vCipher, vAAD, vTag);
end;

uses
  sgcCrypto_Random, sgcCrypto_Ed25519, sgcCrypto_MLKEM;
var
  vSeed, vMessage, vSignature: TBytes;
  vPublicKey, vPrivateKey, vCiphertext, vSharedSecret: TBytes;
begin
  // Ed25519 signature from a 32-byte seed
  vSeed      := sgcRandomBytes(32);
  vMessage   := TEncoding.UTF8.GetBytes('sign me');
  vSignature := sgcEd25519_Sign(vSeed, vMessage);

  // ML-KEM-768: post-quantum key encapsulation (FIPS 203)
  sgcMLKEM_GenerateKeyPair(mlkem768, vPublicKey, vPrivateKey);
  sgcMLKEM_Encapsulate(mlkem768, vPublicKey, vCiphertext, vSharedSecret);

  // The peer recovers the same secret from the ciphertext
  sgcMLKEM_Decapsulate(mlkem768, vPrivateKey, vCiphertext, vSharedSecret);
end;