identity.h File Reference

Identity key management for discovery server. More...

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Functions
asciichat_error_t	acds_identity_generate (uint8_t public_key[32], uint8_t secret_key[64])
	Generate new Ed25519 keypair.
asciichat_error_t	acds_identity_load (const char *path, uint8_t public_key[32], uint8_t secret_key[64])
	Load identity from file.
asciichat_error_t	acds_identity_save (const char *path, const uint8_t public_key[32], const uint8_t secret_key[64])
	Save identity to file.
void	acds_identity_fingerprint (const uint8_t public_key[32], char fingerprint[65])
	Compute SHA256 fingerprint of public key.
asciichat_error_t	acds_identity_default_path (char *path_out, size_t path_size)
	Get default identity file path for current platform.

Detailed Description

Identity key management for discovery server.

Simple Ed25519 key generation, storage, and fingerprint computation. This is a minimal inline implementation - will be refactored to lib/identity/ in the future when we add randomart and other features.

Definition in file identity.h.

Function Documentation

acds_identity_default_path()

asciichat_error_t acds_identity_default_path	(	char *	path_out,
		size_t	path_size
	)

Get default identity file path for current platform.

Parameters

path_out	Output buffer for path (should be at least 256 bytes)
path_size	Size of output buffer

Returns

ASCIICHAT_OK on success, error code otherwise

Returns:

• Unix: ~/.config/ascii-chat/acds_identity
• Windows: APPDATA%\ascii-chat\acds_identity

Definition at line 198 of file identity.c.

                                                                               {
  if (!path_out || path_size == 0) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "path_out cannot be NULL and path_size must be > 0");
  }
 
#ifdef _WIN32
  // Windows: %APPDATA%\ascii-chat\acds_identity
  const char *appdata = SAFE_GETENV("APPDATA");
  if (!appdata) {
    return SET_ERRNO(ERROR_CONFIG, "APPDATA environment variable not set");
  }
 
  int written = snprintf(path_out, path_size, "%s\\ascii-chat\\acds_identity", appdata);
  if (written < 0 || (size_t)written >= path_size) {
    return SET_ERRNO(ERROR_CONFIG, "Path buffer too small");
  }
#else
  // Unix: ~/.config/ascii-chat/acds_identity
  const char *home = SAFE_GETENV("HOME");
  if (!home) {
    return SET_ERRNO(ERROR_CONFIG, "HOME environment variable not set");
  }
 
  // Check for XDG_CONFIG_HOME
  const char *xdg_config = SAFE_GETENV("XDG_CONFIG_HOME");
  if (xdg_config && xdg_config[0] != '\0') {
    int written = snprintf(path_out, path_size, "%s/ascii-chat/acds_identity", xdg_config);
    if (written < 0 || (size_t)written >= path_size) {
      return SET_ERRNO(ERROR_CONFIG, "Path buffer too small");
    }
  } else {
    int written = snprintf(path_out, path_size, "%s/.config/ascii-chat/acds_identity", home);
    if (written < 0 || (size_t)written >= path_size) {
      return SET_ERRNO(ERROR_CONFIG, "Path buffer too small");
    }
  }
#endif
 
  return ASCIICHAT_OK;
}

References ASCIICHAT_OK, ERROR_CONFIG, ERROR_INVALID_PARAM, SAFE_GETENV, and SET_ERRNO.

acds_identity_fingerprint()

void acds_identity_fingerprint	(	const uint8_t	public_key[32],
		char	fingerprint[65]
	)

Compute SHA256 fingerprint of public key.

Parameters

public_key	32-byte Ed25519 public key
fingerprint	Output buffer for 65 bytes (64 hex chars + null terminator)

Definition at line 181 of file identity.c.

                                                                                   {
  if (!public_key || !fingerprint) {
    log_error("acds_identity_fingerprint: NULL parameters");
    return;
  }
 
  // Compute SHA256 hash of public key
  uint8_t hash[32];
  crypto_hash_sha256(hash, public_key, 32);
 
  // Convert to hex string
  for (int i = 0; i < 32; i++) {
    sprintf(&fingerprint[i * 2], "%02x", hash[i]);
  }
  fingerprint[64] = '\0';
}

References log_error.

Referenced by main().

acds_identity_generate()

asciichat_error_t acds_identity_generate	(	uint8_t	public_key[32],
		uint8_t	secret_key[64]
	)

Generate new Ed25519 keypair.

Parameters

public_key	Output buffer for 32-byte public key
secret_key	Output buffer for 64-byte secret key

Returns

ASCIICHAT_OK on success, error code otherwise

Definition at line 21 of file identity.c.

                                                                                         {
  if (!public_key || !secret_key) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "public_key and secret_key cannot be NULL");
  }
 
  // Generate Ed25519 keypair using libsodium
  if (crypto_sign_keypair(public_key, secret_key) != 0) {
    return SET_ERRNO(ERROR_CRYPTO, "Failed to generate Ed25519 keypair");
  }
 
  log_debug("Generated new Ed25519 identity keypair");
  return ASCIICHAT_OK;
}

References ASCIICHAT_OK, ERROR_CRYPTO, ERROR_INVALID_PARAM, log_debug, and SET_ERRNO.

Referenced by main().

acds_identity_load()

asciichat_error_t acds_identity_load	(	const char *	path,
		uint8_t	public_key[32],
		uint8_t	secret_key[64]
	)

Load identity from file.

Parameters

path	Path to identity file (e.g., ~/.config/ascii-chat/acds_identity)
public_key	Output buffer for 32-byte public key
secret_key	Output buffer for 64-byte secret key

Returns

ASCIICHAT_OK on success, ERROR_CONFIG if file doesn't exist

Definition at line 35 of file identity.c.

                                                                                                       {
  if (!path || !public_key || !secret_key) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "path, public_key, and secret_key cannot be NULL");
  }
 
  // Open file for reading
  FILE *fp = fopen(path, "rb");
  if (!fp) {
    if (errno == ENOENT) {
      return SET_ERRNO(ERROR_CONFIG, "Identity file does not exist: %s", path);
    }
    return SET_ERRNO_SYS(ERROR_CONFIG, "Failed to open identity file: %s", path);
  }
 
  // Read secret key (64 bytes)
  size_t read = fread(secret_key, 1, 64, fp);
  if (read != 64) {
    fclose(fp);
    return SET_ERRNO(ERROR_CONFIG, "Identity file corrupted (expected 64 bytes, got %zu): %s", read, path);
  }
 
  // Extract public key from secret key (last 32 bytes of Ed25519 secret key)
  memcpy(public_key, secret_key + 32, 32);
 
  fclose(fp);
  log_info("Loaded identity from %s", path);
  return ASCIICHAT_OK;
}

References ASCIICHAT_OK, errno, ERROR_CONFIG, ERROR_INVALID_PARAM, log_info, SET_ERRNO, and SET_ERRNO_SYS.

Referenced by main().

acds_identity_save()

asciichat_error_t acds_identity_save	(	const char *	path,
		const uint8_t	public_key[32],
		const uint8_t	secret_key[64]
	)

Save identity to file.

Parameters

path	Path to identity file
public_key	32-byte public key
secret_key	64-byte secret key

Returns

ASCIICHAT_OK on success, error code otherwise

Definition at line 138 of file identity.c.

                                                                                                                   {
  if (!path || !public_key || !secret_key) {
    return SET_ERRNO(ERROR_INVALID_PARAM, "path, public_key, and secret_key cannot be NULL");
  }
 
  // Extract directory path and create all parent directories
  char dir_path[512];
  SAFE_STRNCPY(dir_path, path, sizeof(dir_path));
 
  // Find last directory separator
  char *last_sep = strrchr(dir_path, '/');
  if (!last_sep) {
    last_sep = strrchr(dir_path, '\\');
  }
 
  if (last_sep) {
    *last_sep = '\0';
 
    // Create directory recursively (mkdir -p equivalent)
    asciichat_error_t result = ensure_directory_exists(dir_path);
    if (result != ASCIICHAT_OK) {
      return result;
    }
  }
 
  // Open file for writing (mode 0600 = owner read/write only)
  int fd = platform_open(path, O_WRONLY | O_CREAT | O_TRUNC, 0600);
  if (fd < 0) {
    return SET_ERRNO_SYS(ERROR_CONFIG, "Failed to create identity file: %s", path);
  }
 
  // Write secret key (64 bytes)
  ssize_t written = write(fd, secret_key, 64);
  close(fd);
 
  if (written != 64) {
    return SET_ERRNO(ERROR_CONFIG, "Failed to write identity file (wrote %zd/64 bytes): %s", written, path);
  }
 
  log_info("Saved identity to %s", path);
  return ASCIICHAT_OK;
}

References ASCIICHAT_OK, ERROR_CONFIG, ERROR_INVALID_PARAM, log_info, platform_open(), SAFE_STRNCPY, SET_ERRNO, and SET_ERRNO_SYS.

Referenced by main().