crypto_aes_gcm.h

#ifndef SOURCEMETA_CORE_CRYPTO_AES_GCM_H_
#define SOURCEMETA_CORE_CRYPTO_AES_GCM_H_
 
#ifndef SOURCEMETA_CORE_CRYPTO_EXPORT
#include <sourcemeta/core/crypto_export.h>
#endif
 
#include <cassert>     // assert
#include <optional>    // std::optional
#include <string>      // std::string
#include <string_view> // std::string_view
 
namespace sourcemeta::core {

struct AESGCMCiphertext {
  std::string data;

  [[nodiscard]] auto ciphertext() const -> std::string_view {
    assert(this->data.size() >= 16);
    return std::string_view{this->data}.substr(0, this->data.size() - 16);
  }

  [[nodiscard]] auto tag() const -> std::string_view {
    assert(this->data.size() >= 16);
    return std::string_view{this->data}.substr(this->data.size() - 16);
  }
};

auto SOURCEMETA_CORE_CRYPTO_EXPORT aes_gcm_encrypt(
    const std::string_view key, const std::string_view iv,
    const std::string_view associated_data, const std::string_view plaintext)
    -> std::optional<AESGCMCiphertext>;

auto SOURCEMETA_CORE_CRYPTO_EXPORT aes_gcm_decrypt(
    const std::string_view key, const std::string_view iv,
    const std::string_view associated_data, const std::string_view ciphertext,
    const std::string_view tag) -> std::optional<std::string>;

auto SOURCEMETA_CORE_CRYPTO_EXPORT
aes_256_gcm_seal(const std::string_view key, const std::string_view plaintext)
    -> std::optional<std::string>;

auto SOURCEMETA_CORE_CRYPTO_EXPORT
aes_256_gcm_unseal(const std::string_view key, const std::string_view sealed)
    -> std::optional<std::string>;
 
} // namespace sourcemeta::core
 
#endif