aboutsummaryrefslogtreecommitdiffstats
path: root/util-src/crypto.c
blob: c5ecf9ab7ff21a8e0d7cf2b9a8e167a8f1fcaff3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
/* Prosody IM
-- Copyright (C) 2022 Matthew Wild
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--
*/

/*
* crypto.c
* Lua library for cryptographic operations using OpenSSL
*/

#include <string.h>
#include <stdlib.h>

#ifdef _MSC_VER
typedef unsigned __int32 uint32_t;
#else
#include <inttypes.h>
#endif

#include "lua.h"
#include "lauxlib.h"
#include <openssl/crypto.h>
#include <openssl/ecdsa.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/obj_mac.h>
#include <openssl/pem.h>

#if (LUA_VERSION_NUM == 501)
#define luaL_setfuncs(L, R, N) luaL_register(L, NULL, R)
#endif

#include "managed_pointer.h"

#define PKEY_MT_TAG "util.crypto key"

static BIO* new_memory_BIO() {
	return BIO_new(BIO_s_mem());
}

MANAGED_POINTER_ALLOCATOR(new_managed_EVP_MD_CTX, EVP_MD_CTX*, EVP_MD_CTX_new, EVP_MD_CTX_free)
MANAGED_POINTER_ALLOCATOR(new_managed_BIO_s_mem, BIO*, new_memory_BIO, BIO_free)
MANAGED_POINTER_ALLOCATOR(new_managed_EVP_CIPHER_CTX, EVP_CIPHER_CTX*, EVP_CIPHER_CTX_new, EVP_CIPHER_CTX_free)

#define CRYPTO_KEY_TYPE_ERR "unexpected key type: got '%s', expected '%s'"

static EVP_PKEY* pkey_from_arg(lua_State *L, int idx, const int type, const int require_private) {
	EVP_PKEY *pkey = *(EVP_PKEY**)luaL_checkudata(L, idx, PKEY_MT_TAG);
	int got_type;
	if(type || require_private) {
		lua_getuservalue(L, idx);
		if(type != 0) {
			lua_getfield(L, -1, "type");
			got_type = lua_tointeger(L, -1);
			if(got_type != type) {
				const char *got_key_type_name = OBJ_nid2sn(got_type);
				const char *want_key_type_name = OBJ_nid2sn(type);
				lua_pushfstring(L, CRYPTO_KEY_TYPE_ERR, got_key_type_name, want_key_type_name);
				luaL_argerror(L, idx, lua_tostring(L, -1));
			}
			lua_pop(L, 1);
		}
		if(require_private != 0) {
			lua_getfield(L, -1, "private");
			if(lua_toboolean(L, -1) != 1) {
				luaL_argerror(L, idx, "private key expected, got public key only");
			}
			lua_pop(L, 1);
		}
		lua_pop(L, 1);
	}
	return pkey;
}

static int Lpkey_finalizer(lua_State *L) {
	EVP_PKEY *pkey = pkey_from_arg(L, 1, 0, 0);
	EVP_PKEY_free(pkey);
	return 0;
}

static int Lpkey_meth_get_type(lua_State *L) {
	EVP_PKEY *pkey = pkey_from_arg(L, 1, 0, 0);

	int key_type = EVP_PKEY_id(pkey);
	lua_pushstring(L, OBJ_nid2sn(key_type));
	return 1;
}

static int base_evp_sign(lua_State *L, const int key_type, const EVP_MD *digest_type) {
	EVP_PKEY *pkey = pkey_from_arg(L, 1, (key_type!=NID_rsassaPss)?key_type:NID_rsaEncryption, 1);
	luaL_Buffer sigbuf;

	size_t msg_len;
	const unsigned char* msg = (unsigned char*)lua_tolstring(L, 2, &msg_len);

	size_t sig_len;
	unsigned char *sig = NULL;
	EVP_MD_CTX *md_ctx = new_managed_EVP_MD_CTX(L);

	if(EVP_DigestSignInit(md_ctx, NULL, digest_type, NULL, pkey) != 1) {
		lua_pushnil(L);
		return 1;
	}
	if(key_type == NID_rsassaPss) {
		EVP_PKEY_CTX_set_rsa_padding(EVP_MD_CTX_pkey_ctx(md_ctx), RSA_PKCS1_PSS_PADDING);
	}
	if(EVP_DigestSign(md_ctx, NULL, &sig_len, msg, msg_len) != 1) {
		lua_pushnil(L);
		return 1;
	}

	// COMPAT w/ Lua 5.1
	luaL_buffinit(L, &sigbuf);
	sig = memset(luaL_prepbuffer(&sigbuf), 0, sig_len);

	if(EVP_DigestSign(md_ctx, sig, &sig_len, msg, msg_len) != 1) {
		lua_pushnil(L);
	}
	else {
		luaL_addsize(&sigbuf, sig_len);
		luaL_pushresult(&sigbuf);
		return 1;
	}

	return 1;
}

static int base_evp_verify(lua_State *L, const int key_type, const EVP_MD *digest_type) {
	EVP_PKEY *pkey = pkey_from_arg(L, 1, (key_type!=NID_rsassaPss)?key_type:NID_rsaEncryption, 0);

	size_t msg_len;
	const unsigned char *msg = (unsigned char*)luaL_checklstring(L, 2, &msg_len);

	size_t sig_len;
	const unsigned char *sig = (unsigned char*)luaL_checklstring(L, 3, &sig_len);

	EVP_MD_CTX *md_ctx = EVP_MD_CTX_new();

	if(EVP_DigestVerifyInit(md_ctx, NULL, digest_type, NULL, pkey) != 1) {
		lua_pushnil(L);
		goto cleanup;
	}
	if(key_type == NID_rsassaPss) {
		EVP_PKEY_CTX_set_rsa_padding(EVP_MD_CTX_pkey_ctx(md_ctx), RSA_PKCS1_PSS_PADDING);
	}
	int result = EVP_DigestVerify(md_ctx, sig, sig_len, msg, msg_len);
	if(result == 0) {
		lua_pushboolean(L, 0);
	} else if(result != 1) {
		lua_pushnil(L);
	}
	else {
		lua_pushboolean(L, 1);
	}
cleanup:
	EVP_MD_CTX_free(md_ctx);
	return 1;
}

static int Lpkey_meth_public_pem(lua_State *L) {
	char *data;
	size_t bytes;
	EVP_PKEY *pkey = pkey_from_arg(L, 1, 0, 0);
	BIO *bio = new_managed_BIO_s_mem(L);
	if(PEM_write_bio_PUBKEY(bio, pkey)) {
		bytes = BIO_get_mem_data(bio, &data);
		if (bytes > 0) {
			lua_pushlstring(L, data, bytes);
		}
		else {
			lua_pushnil(L);
		}
	}
	else {
		lua_pushnil(L);
	}
	return 1;
}

static int Lpkey_meth_private_pem(lua_State *L) {
	char *data;
	size_t bytes;
	EVP_PKEY *pkey = pkey_from_arg(L, 1, 0, 1);
	BIO *bio = new_managed_BIO_s_mem(L);

	if(PEM_write_bio_PrivateKey(bio, pkey, NULL, NULL, 0, NULL, NULL)) {
		bytes = BIO_get_mem_data(bio, &data);
		if (bytes > 0) {
			lua_pushlstring(L, data, bytes);
		}
		else {
			lua_pushnil(L);
		}
	}
	else {
		lua_pushnil(L);
	}
	return 1;
}

static int push_pkey(lua_State *L, EVP_PKEY *pkey, const int type, const int privkey) {
	EVP_PKEY **ud = lua_newuserdata(L, sizeof(EVP_PKEY*));
	*ud = pkey;
	luaL_newmetatable(L, PKEY_MT_TAG);
	lua_setmetatable(L, -2);

	/* Set some info about the key and attach it as a user value */
	lua_newtable(L);
	if(type != 0) {
		lua_pushinteger(L, type);
		lua_setfield(L, -2, "type");
	}
	if(privkey != 0) {
		lua_pushboolean(L, 1);
		lua_setfield(L, -2, "private");
	}
	lua_setuservalue(L, -2);
	return 1;
}

static int Lgenerate_ed25519_keypair(lua_State *L) {
	EVP_PKEY *pkey = NULL;
	EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_ED25519, NULL);

	/* Generate key */
	EVP_PKEY_keygen_init(pctx);
	EVP_PKEY_keygen(pctx, &pkey);
	EVP_PKEY_CTX_free(pctx);

	push_pkey(L, pkey, NID_ED25519, 1);
	return 1;
}

static int Limport_private_pem(lua_State *L) {
	EVP_PKEY *pkey = NULL;

	size_t privkey_bytes;
	const char* privkey_data;
	BIO *bio = new_managed_BIO_s_mem(L);

	privkey_data = luaL_checklstring(L, 1, &privkey_bytes);
	BIO_write(bio, privkey_data, privkey_bytes);
	pkey = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL);
	if (pkey) {
		push_pkey(L, pkey, EVP_PKEY_id(pkey), 1);
	}
	else {
		lua_pushnil(L);
	}

	return 1;
}

static int Limport_public_pem(lua_State *L) {
	EVP_PKEY *pkey = NULL;

	size_t pubkey_bytes;
	const char* pubkey_data;
	BIO *bio = new_managed_BIO_s_mem(L);

	pubkey_data = luaL_checklstring(L, 1, &pubkey_bytes);
	BIO_write(bio, pubkey_data, pubkey_bytes);
	pkey = PEM_read_bio_PUBKEY(bio, NULL, NULL, NULL);
	if (pkey) {
		push_pkey(L, pkey, EVP_PKEY_id(pkey), 0);
	}
	else {
		lua_pushnil(L);
	}

	return 1;
}

static int Led25519_sign(lua_State *L) {
	return base_evp_sign(L, NID_ED25519, NULL);
}

static int Led25519_verify(lua_State *L) {
	return base_evp_verify(L, NID_ED25519, NULL);
}

/* gcm_encrypt(key, iv, plaintext) */
static int Laes_gcm_encrypt(lua_State *L, const EVP_CIPHER *cipher, const unsigned char expected_key_len) {
	EVP_CIPHER_CTX *ctx;
	luaL_Buffer ciphertext_buffer;

	size_t key_len, iv_len, plaintext_len;
	int ciphertext_len, final_len;

	const unsigned char *key = (unsigned char*)luaL_checklstring(L, 1, &key_len);
	const unsigned char *iv = (unsigned char*)luaL_checklstring(L, 2, &iv_len);
	const unsigned char *plaintext = (unsigned char*)luaL_checklstring(L, 3, &plaintext_len);

	if(key_len != expected_key_len) {
		return luaL_error(L, "key must be %d bytes", expected_key_len);
	}
	luaL_argcheck(L, iv_len == 12, 2, "iv must be 12 bytes");
	if(lua_gettop(L) > 3) {
		return luaL_error(L, "Expected 3 arguments, got %d", lua_gettop(L));
	}

	// Create and initialise the context
	ctx = new_managed_EVP_CIPHER_CTX(L);

	// Initialise the encryption operation
	if(1 != EVP_EncryptInit_ex(ctx, cipher, NULL, NULL, NULL)) {
		return luaL_error(L, "Error while initializing encryption engine");
	}

	// Initialise key and IV
	if(1 != EVP_EncryptInit_ex(ctx, NULL, NULL, key, iv)) {
		return luaL_error(L, "Error while initializing key/iv");
	}

	luaL_buffinit(L, &ciphertext_buffer);
	unsigned char *ciphertext = (unsigned char*)luaL_prepbuffsize(&ciphertext_buffer, plaintext_len+16);

	if(1 != EVP_EncryptUpdate(ctx, ciphertext, &ciphertext_len, plaintext, plaintext_len)) {
		return luaL_error(L, "Error while encrypting data");
	}

	/*
	* Finalise the encryption. Normally ciphertext bytes may be written at
	* this stage, but this does not occur in GCM mode
	*/
	if(1 != EVP_EncryptFinal_ex(ctx, ciphertext + ciphertext_len, &final_len)) {
		return luaL_error(L, "Error while encrypting final data");
	}
	if(final_len != 0) {
		return luaL_error(L, "Non-zero final data");
	}

	/* Get the tag */
	if(1 != EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, 16, ciphertext + ciphertext_len)) {
		return luaL_error(L, "Unable to read AEAD tag of encrypted data");
	}

	luaL_addsize(&ciphertext_buffer, ciphertext_len + 16);
	luaL_pushresult(&ciphertext_buffer);

	return 1;
}

static int Laes_128_gcm_encrypt(lua_State *L) {
	return Laes_gcm_encrypt(L, EVP_aes_128_gcm(), 16);
}

static int Laes_256_gcm_encrypt(lua_State *L) {
	return Laes_gcm_encrypt(L, EVP_aes_256_gcm(), 32);
}

/* gcm_decrypt(key, iv, ciphertext) */
static int Laes_gcm_decrypt(lua_State *L, const EVP_CIPHER *cipher, const unsigned char expected_key_len) {
	EVP_CIPHER_CTX *ctx;
	luaL_Buffer plaintext_buffer;

	size_t key_len, iv_len, ciphertext_len;
	int plaintext_len, final_len;

	const unsigned char *key = (unsigned char*)luaL_checklstring(L, 1, &key_len);
	const unsigned char *iv = (unsigned char*)luaL_checklstring(L, 2, &iv_len);
	const unsigned char *ciphertext = (unsigned char*)luaL_checklstring(L, 3, &ciphertext_len);

	if(key_len != expected_key_len) {
		return luaL_error(L, "key must be %d bytes", expected_key_len);
	}
	luaL_argcheck(L, iv_len == 12, 2, "iv must be 12 bytes");
	luaL_argcheck(L, ciphertext_len > 16, 3, "ciphertext must be at least 16 bytes (including tag)");
	if(lua_gettop(L) > 3) {
		return luaL_error(L, "Expected 3 arguments, got %d", lua_gettop(L));
	}

	/* Create and initialise the context */
	ctx = new_managed_EVP_CIPHER_CTX(L);

	/* Initialise the decryption operation. */
	if(!EVP_DecryptInit_ex(ctx, cipher, NULL, NULL, NULL)) {
		return luaL_error(L, "Error while initializing decryption engine");
	}

	/* Initialise key and IV */
	if(!EVP_DecryptInit_ex(ctx, NULL, NULL, key, iv)) {
		return luaL_error(L, "Error while initializing key/iv");
	}

	luaL_buffinit(L, &plaintext_buffer);
	unsigned char *plaintext = (unsigned char*)luaL_prepbuffsize(&plaintext_buffer, ciphertext_len);

	/*
	* Provide the message to be decrypted, and obtain the plaintext output.
	* EVP_DecryptUpdate can be called multiple times if necessary
	*/
	if(!EVP_DecryptUpdate(ctx, plaintext, &plaintext_len, ciphertext, ciphertext_len-16)) {
		return luaL_error(L, "Error while decrypting data");
	}

	/* Set expected tag value. Works in OpenSSL 1.0.1d and later */
	if(!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, 16, (unsigned char*)ciphertext + (ciphertext_len-16))) {
		return luaL_error(L, "Error while processing authentication tag");
	}

	/*
	* Finalise the decryption. A positive return value indicates success,
	* anything else is a failure - the plaintext is not trustworthy.
	*/
	int ret = EVP_DecryptFinal_ex(ctx, plaintext + plaintext_len, &final_len);

	if(ret <= 0) {
		/* Verify failed */
		lua_pushnil(L);
		lua_pushliteral(L, "verify-failed");
		return 2;
	}

	luaL_addsize(&plaintext_buffer, plaintext_len + final_len);
	luaL_pushresult(&plaintext_buffer);
	return 1;
}

static int Laes_128_gcm_decrypt(lua_State *L) {
	return Laes_gcm_decrypt(L, EVP_aes_128_gcm(), 16);
}

static int Laes_256_gcm_decrypt(lua_State *L) {
	return Laes_gcm_decrypt(L, EVP_aes_256_gcm(), 32);
}

/* r, s = parse_ecdsa_sig(sig_der) */
static int Lparse_ecdsa_signature(lua_State *L) {
	ECDSA_SIG *sig;
	size_t sig_der_len;
	const unsigned char *sig_der = (unsigned char*)luaL_checklstring(L, 1, &sig_der_len);
	const BIGNUM *r, *s;
	unsigned char rb[32];
	unsigned char sb[32];
	int rlen, slen;

	sig = d2i_ECDSA_SIG(NULL, &sig_der, sig_der_len);

	if(sig == NULL) {
		lua_pushnil(L);
		return 1;
	}

	ECDSA_SIG_get0(sig, &r, &s);

	rlen = BN_num_bytes(r);
	slen = BN_num_bytes(s);

	if (rlen > 32 || slen > 32) {
		ECDSA_SIG_free(sig);
		luaL_error(L, "unexpectedly large signature integers");
	}

	BN_bn2bin(r, rb);
	BN_bn2bin(s, sb);

	ECDSA_SIG_free(sig);

	lua_pushlstring(L, (const char*)rb, rlen);
	lua_pushlstring(L, (const char*)sb, slen);

	return 2;
}

/* sig_der = build_ecdsa_signature(r, s) */
static int Lbuild_ecdsa_signature(lua_State *L) {
	ECDSA_SIG *sig = ECDSA_SIG_new();
	BIGNUM *r, *s;
	luaL_Buffer sigbuf;

	size_t rlen, slen;
	const unsigned char *rbin, *sbin;

	rbin = (unsigned char*)luaL_checklstring(L, 1, &rlen);
	sbin = (unsigned char*)luaL_checklstring(L, 2, &slen);

	r = BN_bin2bn(rbin, (int)rlen, NULL);
	s = BN_bin2bn(sbin, (int)slen, NULL);

	ECDSA_SIG_set0(sig, r, s);

	luaL_buffinit(L, &sigbuf);

	unsigned char *buffer = (unsigned char*)luaL_prepbuffsize(&sigbuf, rlen+slen+32);
	int len = i2d_ECDSA_SIG(sig, &buffer);
	luaL_addsize(&sigbuf, len);
	luaL_pushresult(&sigbuf);

	ECDSA_SIG_free(sig);

	return 1;
}

#define REG_SIGN_VERIFY(algorithm, digest) \
	{ #algorithm "_" #digest "_sign",       L ## algorithm ## _ ## digest ## _sign    },\
	{ #algorithm "_" #digest "_verify",     L ## algorithm ## _ ## digest ## _verify  },

#define IMPL_SIGN_VERIFY(algorithm, key_type, digest) \
  static int L ## algorithm ## _ ## digest ## _sign(lua_State *L) {   \
  	return base_evp_sign(L, key_type, EVP_ ## digest());          \
  }                                                                   \
  static int L ## algorithm ## _ ## digest ## _verify(lua_State *L) { \
  	return base_evp_verify(L, key_type, EVP_ ## digest());        \
  }

IMPL_SIGN_VERIFY(ecdsa, NID_X9_62_id_ecPublicKey, sha256)
IMPL_SIGN_VERIFY(ecdsa, NID_X9_62_id_ecPublicKey, sha384)
IMPL_SIGN_VERIFY(ecdsa, NID_X9_62_id_ecPublicKey, sha512)

IMPL_SIGN_VERIFY(rsassa_pkcs1, NID_rsaEncryption, sha256)
IMPL_SIGN_VERIFY(rsassa_pkcs1, NID_rsaEncryption, sha384)
IMPL_SIGN_VERIFY(rsassa_pkcs1, NID_rsaEncryption, sha512)

IMPL_SIGN_VERIFY(rsassa_pss, NID_rsassaPss, sha256)
IMPL_SIGN_VERIFY(rsassa_pss, NID_rsassaPss, sha384)
IMPL_SIGN_VERIFY(rsassa_pss, NID_rsassaPss, sha512)

static const luaL_Reg Reg[] = {
	{ "ed25519_sign",                Led25519_sign             },
	{ "ed25519_verify",              Led25519_verify           },

	REG_SIGN_VERIFY(ecdsa, sha256)
	REG_SIGN_VERIFY(ecdsa, sha384)
	REG_SIGN_VERIFY(ecdsa, sha512)

	REG_SIGN_VERIFY(rsassa_pkcs1, sha256)
	REG_SIGN_VERIFY(rsassa_pkcs1, sha384)
	REG_SIGN_VERIFY(rsassa_pkcs1, sha512)

	REG_SIGN_VERIFY(rsassa_pss, sha256)
	REG_SIGN_VERIFY(rsassa_pss, sha384)
	REG_SIGN_VERIFY(rsassa_pss, sha512)

	{ "aes_128_gcm_encrypt",         Laes_128_gcm_encrypt      },
	{ "aes_128_gcm_decrypt",         Laes_128_gcm_decrypt      },
	{ "aes_256_gcm_encrypt",         Laes_256_gcm_encrypt      },
	{ "aes_256_gcm_decrypt",         Laes_256_gcm_decrypt      },

	{ "generate_ed25519_keypair",    Lgenerate_ed25519_keypair },

	{ "import_private_pem",          Limport_private_pem       },
	{ "import_public_pem",           Limport_public_pem        },

	{ "parse_ecdsa_signature",       Lparse_ecdsa_signature    },
	{ "build_ecdsa_signature",       Lbuild_ecdsa_signature    },
	{ NULL,                          NULL                      }
};

static const luaL_Reg KeyMethods[] = {
	{ "private_pem",            Lpkey_meth_private_pem       },
	{ "public_pem",             Lpkey_meth_public_pem        },
	{ "get_type",               Lpkey_meth_get_type          },
	{ NULL,                     NULL                         }
};

static const luaL_Reg KeyMetatable[] = {
	{ "__gc",               Lpkey_finalizer },
	{ NULL,                 NULL            }
};

LUALIB_API int luaopen_util_crypto(lua_State *L) {
#if (LUA_VERSION_NUM > 501)
	luaL_checkversion(L);
#endif

	/* Initialize pkey metatable */
	luaL_newmetatable(L, PKEY_MT_TAG);
	luaL_setfuncs(L, KeyMetatable, 0);
	lua_newtable(L);
	luaL_setfuncs(L, KeyMethods, 0);
	lua_setfield(L, -2, "__index");
	lua_pop(L, 1);

	/* Initialize lib table */
	lua_newtable(L);
	luaL_setfuncs(L, Reg, 0);
	lua_pushliteral(L, "-3.14");
	lua_setfield(L, -2, "version");
#ifdef OPENSSL_VERSION
	lua_pushstring(L, OpenSSL_version(OPENSSL_VERSION));
	lua_setfield(L, -2, "_LIBCRYPTO_VERSION");
#endif
	return 1;
}