package CryptX;

use strict;
use warnings ;
our $VERSION = '0.090';

require XSLoader;
XSLoader::load('CryptX', $VERSION);

use Carp;
my $has_json;

BEGIN {
  $has_json = 1 if eval { require JSON; 1 };
}

sub _croak {
  die @_ if ref $_[0] || !$_[-1];
  if ($_[-1] =~ /^(.*)( at .+ line .+\n$)/s) {
    pop @_;
    push @_, $1;
  }
  die Carp::shortmess @_;
}

sub _decode_json {
  croak "FATAL: cannot find JSON module" if !$has_json;
  return JSON->new->utf8->decode(shift);
}

sub _encode_json {
  croak "FATAL: cannot find JSON module" if !$has_json;
  return JSON->new->utf8->canonical->encode(shift);
}

1;

=pod

=head1 NAME

CryptX - Cryptographic toolkit

=head1 SYNOPSIS

CryptX is the distribution entry point. In normal code, load one of the concrete modules listed below.

 ## one-shot hashing
 use Crypt::Digest qw(digest_data_hex);
 my $sha256 = digest_data_hex('SHA256', 'hello world');

 ## classic AES-CBC encryption with padding
 use Crypt::Mode::CBC;
 my $cbc = Crypt::Mode::CBC->new('AES');
 my $iv = random_bytes(16); # 16-byte AES block-size IV
 my $cbc_ciphertext = $cbc->encrypt('hello world', $key, $iv);

 ## authenticated encryption (AEAD) with AES
 use Crypt::AuthEnc::GCM qw(gcm_encrypt_authenticate);
 my $key = random_bytes(32);   # 32-byte AES-256 key
 my $nonce = random_bytes(12); # 12-byte unique nonce
 my ($ciphertext, $tag) = gcm_encrypt_authenticate('AES', $key, $nonce, 'header', 'hello world');

 ## message authentication
 use Crypt::Mac::HMAC qw(hmac_hex);
 my $mac = hmac_hex('SHA256', $key, 'hello world');

 ## secure random data + UUID helpers
 use Crypt::PRNG qw(random_bytes random_string);
 use Crypt::Misc qw(random_v4uuid random_v7uuid);
 my $salt = random_bytes(16);
 my $token = random_string(24);
 my $uuid4 = random_v4uuid();
 my $uuid7 = random_v7uuid();

 ## classic password-based key derivation
 use Crypt::KeyDerivation qw(pbkdf2);
 my $dk = pbkdf2('password', $salt, 100_000, 'SHA256', 32);

 ## bare stream cipher (authenticate separately)
 use Crypt::Stream::ChaCha;
 my $stream = Crypt::Stream::ChaCha->new($key, $nonce);
 my $stream_ciphertext = $stream->crypt('hello world');

 ## modern signatures
 use Crypt::PK::Ed25519;
 my $signer = Crypt::PK::Ed25519->new->generate_key;
 my $sig = $signer->sign_message('hello world');
 my $ok = $signer->verify_message($sig, 'hello world');

 ## key agreement
 use Crypt::PK::X25519;
 my $alice = Crypt::PK::X25519->new->generate_key;
 my $bob = Crypt::PK::X25519->new->generate_key;
 my $shared_secret = $alice->shared_secret($bob);

=head1 DESCRIPTION

Perl cryptographic modules built on the bundled L<LibTomCrypt|https://github.com/libtom/libtomcrypt> library.
The distribution also includes L<Math::BigInt::LTM>, a L<Math::BigInt> backend
built on the bundled L<LibTomMath|https://www.libtom.net/LibTomMath/> library
used internally by LibTomCrypt.

This module mainly serves as the top-level distribution/documentation page. For actual work,
use one of the concrete modules listed below.

=head2 Algorithm Selection Guide

=head3 Authenticated Encryption (AEAD)

For new designs, prefer authenticated encryption (AEAD) over bare cipher modes:

=over

=item * B<ChaCha20-Poly1305> (L<Crypt::AuthEnc::ChaCha20Poly1305>) - Fast, constant-time,
widely deployed (TLS 1.3, WireGuard, SSH). Use this as the default AEAD choice.

=item * B<XChaCha20-Poly1305> (L<Crypt::AuthEnc::XChaCha20Poly1305>) - Extended 24-byte nonce
variant. Prefer over ChaCha20-Poly1305 when nonces are generated randomly.

=item * B<AES-GCM> (L<Crypt::AuthEnc::GCM>) - The standard AEAD mode for AES. Hardware-accelerated
on modern CPUs. Requires unique nonces; nonce reuse breaks the security entirely.

=item * B<AES-SIV> (L<Crypt::AuthEnc::SIV>) - Deterministic AEAD, nonce-misuse resistant.
Slightly slower but safer when nonce uniqueness cannot be guaranteed.

=item * B<AES-GCM-SIV> (L<Crypt::AuthEnc::GCMSIV>) - Nonce-misuse-resistant AEAD (RFC 8452).
Faster than AES-SIV; pick this when you need GCM-like performance with nonce-reuse safety.

=item * B<AES-OCB> (L<Crypt::AuthEnc::OCB>) - Very fast single-pass AEAD. Check patent status
for your jurisdiction.

=item * B<AES-EAX> (L<Crypt::AuthEnc::EAX>) - Two-pass AEAD based on CTR+OMAC. No patents,
no nonce-length restrictions.

=item * B<AES-CCM> (L<Crypt::AuthEnc::CCM>) - Used in WiFi (WPA2) and Bluetooth. Requires
knowing the plaintext length in advance.

=back

=head3 Cryptographically Secure Randomness and UUIDs

=over

=item * B<Random bytes / strings> (L<Crypt::PRNG>) - Use this for salts, keys, nonces, tokens,
and any other secret random values. The functional helpers
C<random_bytes>, C<random_bytes_hex>, C<random_bytes_b64>, C<random_bytes_b64u>,
C<random_string>, and C<random_string_from> cover most use cases. The OO API
and the algorithm-specific wrappers (L<Crypt::PRNG::ChaCha20>, L<Crypt::PRNG::Fortuna>, etc.)
are mainly for deterministic streams or interoperability with a specific PRNG.

=item * B<UUIDs> (L<Crypt::Misc/random_v4uuid>, L<Crypt::Misc/random_v7uuid>) - Use C<random_v4uuid>
for opaque random identifiers. Use C<random_v7uuid> when you want roughly time-ordered identifiers
that sort by creation time at millisecond granularity. UUIDs are identifiers, not replacements for
secret random bytes.

=back

=head3 Stream Ciphers

Stream ciphers encrypt data byte-by-byte without block padding. For most
applications prefer an AEAD mode (see above) which bundles encryption with
authentication. Use bare stream ciphers only when you handle authentication
separately.

=over

=item * B<ChaCha> (L<Crypt::Stream::ChaCha>) - The default stream cipher choice.
Same core as ChaCha20-Poly1305 without the built-in MAC.

=item * B<XChaCha> (L<Crypt::Stream::XChaCha>) - Extended 24-byte nonce variant of ChaCha.
Prefer when nonces are generated randomly.

=item * B<Salsa20> / B<XSalsa20> (L<Crypt::Stream::Salsa20>, L<Crypt::Stream::XSalsa20>) -
Predecessor of ChaCha. Prefer ChaCha for new designs; Salsa20 only for
interoperability (e.g. NaCl/libsodium).

=item * B<RC4> (L<Crypt::Stream::RC4>) - B<Broken; do not use for new designs.> Provided for
legacy interoperability only.

=item * B<Rabbit>, B<Sober128>, B<Sosemanuk> (L<Crypt::Stream::Rabbit>, L<Crypt::Stream::Sober128>, L<Crypt::Stream::Sosemanuk>) -
Niche ciphers from the eSTREAM portfolio. Use ChaCha unless a specific protocol requires one of these.

=back

=head3 Block Cipher Modes (without authentication)

Use these only when authentication is handled separately or not needed:

=over

=item * B<CTR> (L<Crypt::Mode::CTR>) - Turns a block cipher into a stream cipher. Parallelizable.

=item * B<CBC> (L<Crypt::Mode::CBC>) - Classic mode, needs padding. Prefer CTR or an AEAD mode.

=item * B<ECB> (L<Crypt::Mode::ECB>) - B<Insecure for most uses.> Each block encrypted independently.

=back

The individual L<Crypt::Cipher::AES>, L<Crypt::Cipher::Twofish>, etc. modules implement
raw single-block encryption and are rarely used directly. In almost all cases you should
use them through an AEAD mode (L<Crypt::AuthEnc::GCM>, L<Crypt::AuthEnc::CCM>) or a block
cipher mode (L<Crypt::Mode::CBC>, L<Crypt::Mode::CTR>) instead. When choosing a cipher,
B<AES> is the default; it is hardware-accelerated on most modern CPUs.

=head3 Hash Functions

=over

=item * B<SHA-256> / B<SHA-384> / B<SHA-512> (L<Crypt::Digest::SHA256>, etc.) - The default
choice for general hashing. Widely supported and well analyzed.

=item * B<SHA3-256> / B<SHA3-512> (L<Crypt::Digest::SHA3_256>, etc.) - Alternative to SHA-2
with a completely different construction (Keccak sponge).

=item * B<BLAKE2b> / B<BLAKE2s> (L<Crypt::Digest::BLAKE2b_256>, etc.) - Very fast, especially
in software. BLAKE2b for 64-bit platforms, BLAKE2s for 32-bit.

=item * B<SHAKE> / B<TurboSHAKE> / B<KangarooTwelve> - Extendable-output functions (XOFs).
Use when you need variable-length output.

=back

=head3 Checksums

Use L<Crypt::Checksum::CRC32> and L<Crypt::Checksum::Adler32> only for
non-adversarial integrity checks such as accidental corruption detection.
They are not cryptographic integrity or authenticity mechanisms. For
cryptographic use, prefer L<Crypt::Digest>, L<Crypt::Mac>, or an AEAD mode
from L<Crypt::AuthEnc>.

=head3 Message Authentication Codes

=over

=item * B<HMAC> (L<Crypt::Mac::HMAC>) - The standard MAC construction. Works with any hash.
Use HMAC-SHA256 as the default.

=item * B<Poly1305> (L<Crypt::Mac::Poly1305>) - One-time MAC, very fast. Used as part of
ChaCha20-Poly1305. Requires a unique key per message.

=item * B<BLAKE2b-MAC> (L<Crypt::Mac::BLAKE2b>) - Keyed BLAKE2. Faster than HMAC-SHA256 in
software.

=item * B<CMAC/OMAC> (L<Crypt::Mac::OMAC>) - Block-cipher-based MAC. Use when you already
have AES but not a hash function.

=back

=head3 Public-Key Cryptography

=over

=item * B<Ed25519> (L<Crypt::PK::Ed25519>) - Modern digital signatures. Fast, constant-time,
small keys/signatures. The default choice for new signature schemes.

=item * B<Ed448> (L<Crypt::PK::Ed448>) - Higher security margin than Ed25519 (~224-bit vs ~128-bit).

=item * B<X25519> (L<Crypt::PK::X25519>) - Elliptic-curve Diffie-Hellman key agreement. The
default choice for key exchange.

=item * B<X448> (L<Crypt::PK::X448>) - Higher security margin than X25519.

=item * B<ECDSA> (L<Crypt::PK::ECC>) - Widely used (TLS, Bitcoin). Prefer Ed25519 for new
designs unless ECDSA is required for interoperability.

=item * B<RSA> (L<Crypt::PK::RSA>) - Legacy but very widely used. Use 2048-bit keys minimum, 4096-bit
preferred. Prefer OAEP for encryption and PSS for signatures.

=item * B<DSA> (L<Crypt::PK::DSA>) - Legacy. Prefer Ed25519 or ECDSA.

=item * B<DH> (L<Crypt::PK::DH>) - Classic Diffie-Hellman. Prefer X25519 for new designs.

=back

=head3 Key Derivation / Password hashing

=over

=item * B<HKDF> (L<Crypt::KeyDerivation/hkdf>) - Extract-then-expand KDF. Use for deriving
keys from shared secrets (e.g. after ECDH).

=item * B<Argon2> (L<Crypt::KeyDerivation/argon2_pbkdf>) - Memory-hard password hashing. The
recommended choice for password storage.

=item * B<Bcrypt> (L<Crypt::KeyDerivation/bcrypt_pbkdf>) - Use mainly for compatibility
with formats and protocols that specifically require bcrypt-based key derivation (for example
some OpenSSH workflows). Prefer Argon2 for new password-storage designs.

=item * B<Scrypt> (L<Crypt::KeyDerivation/scrypt_pbkdf>) - Memory-hard KDF. Use Argon2 if available.

=item * B<PBKDF2> (L<Crypt::KeyDerivation/pbkdf2>) - Widely supported but CPU-only hardness.
Use Argon2 or Scrypt when possible.

=item * B<PBKDF1> (L<Crypt::KeyDerivation/pbkdf1>, L<Crypt::KeyDerivation/pbkdf1_openssl>) - Legacy
derivation only. Keep this for interoperability with older formats; do not use it for new designs.

=back

=head2 Error Handling

Most CryptX modules report errors by calling C<croak> (from L<Carp>).
Invalid parameters, unsupported algorithms, wrong key sizes, malformed
input, and internal library failures usually croak with a descriptive
message. Catch exceptions with C<eval> or L<Try::Tiny>.

Some validation-style helpers use a return value instead of croaking. The
most important examples are the C<*_decrypt_verify> functions in the
authenticated encryption modules C<Crypt::AuthEnc::*>.
These return C<undef> when authentication fails, indicating the ciphertext was tampered with
or the wrong key/nonce was used. Some parser/decoder helpers in other modules
also return C<undef> or false for malformed input, so check the concrete
module POD when you need exact failure semantics.

=head2 Module Map

=over

=item * Top-level family modules

L<Crypt::Cipher>, L<Crypt::Mode>, L<Crypt::AuthEnc>,
L<Crypt::Digest>, L<Crypt::Mac>, L<Crypt::Checksum>, L<Crypt::PRNG>,
L<Crypt::PK>, L<Crypt::KeyDerivation>, L<Crypt::Misc>, L<Crypt::ASN1>

=item * Symmetric ciphers

L<Crypt::Cipher::AES>, L<Crypt::Cipher::Anubis>, L<Crypt::Cipher::ARIA>, L<Crypt::Cipher::Blowfish>, L<Crypt::Cipher::Camellia>, L<Crypt::Cipher::CAST5>, L<Crypt::Cipher::DES>,
L<Crypt::Cipher::DES_EDE>, L<Crypt::Cipher::IDEA>, L<Crypt::Cipher::KASUMI>, L<Crypt::Cipher::Khazad>, L<Crypt::Cipher::MULTI2>, L<Crypt::Cipher::Noekeon>,
L<Crypt::Cipher::RC2>, L<Crypt::Cipher::RC5>, L<Crypt::Cipher::RC6>, L<Crypt::Cipher::SAFERP>, L<Crypt::Cipher::SAFER_K128>, L<Crypt::Cipher::SAFER_K64>,
L<Crypt::Cipher::SAFER_SK128>, L<Crypt::Cipher::SAFER_SK64>, L<Crypt::Cipher::SEED>, L<Crypt::Cipher::SM4>, L<Crypt::Cipher::Serpent>, L<Crypt::Cipher::Skipjack>,
L<Crypt::Cipher::Twofish>, L<Crypt::Cipher::XTEA>

=item * Block cipher modes

L<Crypt::Mode::CBC>, L<Crypt::Mode::CFB>, L<Crypt::Mode::CTR>, L<Crypt::Mode::ECB>, L<Crypt::Mode::OFB>

=item * Stream ciphers

L<Crypt::Stream::RC4>, L<Crypt::Stream::ChaCha>, L<Crypt::Stream::XChaCha>, L<Crypt::Stream::Salsa20>, L<Crypt::Stream::XSalsa20>,
L<Crypt::Stream::Sober128>, L<Crypt::Stream::Sosemanuk>, L<Crypt::Stream::Rabbit>

=item * Authenticated encryption modes

L<Crypt::AuthEnc::CCM>, L<Crypt::AuthEnc::EAX>, L<Crypt::AuthEnc::GCM>, L<Crypt::AuthEnc::GCMSIV>, L<Crypt::AuthEnc::OCB>, L<Crypt::AuthEnc::ChaCha20Poly1305>, L<Crypt::AuthEnc::XChaCha20Poly1305>, L<Crypt::AuthEnc::SIV>

=item * Hash functions

L<Crypt::Digest::BLAKE2b_160>, L<Crypt::Digest::BLAKE2b_256>, L<Crypt::Digest::BLAKE2b_384>, L<Crypt::Digest::BLAKE2b_512>,
L<Crypt::Digest::BLAKE2s_128>, L<Crypt::Digest::BLAKE2s_160>, L<Crypt::Digest::BLAKE2s_224>, L<Crypt::Digest::BLAKE2s_256>,
L<Crypt::Digest::CHAES>, L<Crypt::Digest::MD2>, L<Crypt::Digest::MD4>, L<Crypt::Digest::MD5>, L<Crypt::Digest::RIPEMD128>, L<Crypt::Digest::RIPEMD160>,
L<Crypt::Digest::RIPEMD256>, L<Crypt::Digest::RIPEMD320>, L<Crypt::Digest::SHA1>, L<Crypt::Digest::SHA224>, L<Crypt::Digest::SHA256>, L<Crypt::Digest::SHA384>,
L<Crypt::Digest::SHA512>, L<Crypt::Digest::SHA512_224>, L<Crypt::Digest::SHA512_256>, L<Crypt::Digest::Tiger192>, L<Crypt::Digest::Whirlpool>,
L<Crypt::Digest::Keccak224>, L<Crypt::Digest::Keccak256>, L<Crypt::Digest::Keccak384>, L<Crypt::Digest::Keccak512>,
L<Crypt::Digest::SHA3_224>, L<Crypt::Digest::SHA3_256>, L<Crypt::Digest::SHA3_384>, L<Crypt::Digest::SHA3_512>, L<Crypt::Digest::SHAKE>,
L<Crypt::Digest::TurboSHAKE>, L<Crypt::Digest::KangarooTwelve>, L<Crypt::Digest::SM3>

=item * Checksums

L<Crypt::Checksum::Adler32>, L<Crypt::Checksum::CRC32>

=item * Message authentication codes

L<Crypt::Mac::BLAKE2b>, L<Crypt::Mac::BLAKE2s>, L<Crypt::Mac::F9>, L<Crypt::Mac::HMAC>, L<Crypt::Mac::KMAC>,
L<Crypt::Mac::OMAC>, L<Crypt::Mac::Pelican>, L<Crypt::Mac::PMAC>, L<Crypt::Mac::XCBC>, L<Crypt::Mac::Poly1305>

=item * Public-key cryptography

L<Crypt::PK::RSA>, L<Crypt::PK::DSA>, L<Crypt::PK::ECC>, L<Crypt::PK::DH>, L<Crypt::PK::Ed25519>, L<Crypt::PK::X25519>, L<Crypt::PK::Ed448>, L<Crypt::PK::X448>

=item * Cryptographically secure random number generators

L<Crypt::PRNG::Fortuna>, L<Crypt::PRNG::Yarrow>, L<Crypt::PRNG::RC4>, L<Crypt::PRNG::Sober128>, L<Crypt::PRNG::ChaCha20>

=item * Key derivation functions

L<Crypt::KeyDerivation>

=item * ASN.1 parser

L<Crypt::ASN1>

Use C<Crypt::ASN1> only when you need custom ASN.1 / DER parsing or encoding.
Most common key and certificate formats are already handled by the PK modules.

=item * Miscellaneous helpers

L<Crypt::Misc> (base64/base32/base58 codecs, PEM helpers, constant-time compare, UUID generation, octet increment helpers, and related utility functions)

=back

=head2 Diagnostic Functions

These low-level functions expose details of the bundled LibTomCrypt build.
They are intended for troubleshooting and bug reports, not for regular use.

=head3 ltc_build_settings

 my $str = CryptX::ltc_build_settings();

Returns a multi-line string describing every compile-time option that was
enabled when the bundled LibTomCrypt library was built (ciphers, hashes,
MACs, PK algorithms, compiler flags, etc.).

=head3 ltc_mp_name

 my $name = CryptX::ltc_mp_name();
 # e.g. "LTM" (LibTomMath)

Returns the name of the math provider back-end in use.

=head3 ltc_mp_bits_per_digit

 my $bits = CryptX::ltc_mp_bits_per_digit();
 # e.g. 60

Returns the number of bits per digit used by the math provider.

=head2 Math::BigInt backend

Part of CryptX is L<Math::BigInt::LTM>, a L<Math::BigInt> backend based on
the bundled LibTomMath library. It is separate from the cryptographic APIs
above, but it ships in the same distribution and uses the same big-integer
engine that LibTomCrypt relies on.

=head1 LICENSE

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

=head1 COPYRIGHT

Copyright (c) 2013-2026 DCIT, a.s. L<https://www.dcit.cz> / Karel Miko

=cut
