libqaeda

gcrypt.c (30180B)

---

 #ifdef LQ_GPG
 
 #define GPG_MIN_VERSION "1.10.2"
 #define GPG_KEY_TYP 1
 
 #include <gcrypt.h>
 #include <rerr.h>
 #include <llog.h>
 #include <hex.h>
 
 #include "lq/crypto.h"
 #include "lq/io.h"
 #include "lq/mem.h"
 #include "lq/config.h"
 #include "lq/err.h"
 #include "lq/store.h"
 #include "lq/base.h"
 #include "debug.h"
 
 #define CHACHA20_KEY_LENGTH_BYTES 32
 #define CHACHA20_NONCE_LENGTH_BYTES 12
 #define POLY1305_MAC_LEN 16
 #define POLY1305_MAC_KEYLEN 32
 
 /// Lookup mode for key in store.
 enum gpg_find_mode_e {
 	GPG_FIND_MAIN, ///< Use default key filename.
 	GPG_FIND_ORCREATE, ///< Create a new key if not found.
 	GPG_FIND_FINGERPRINT, ///< Load only the key matching the fingerprint.
 };
 
 /// TODO: move create mode to lq/crypto settings
 #ifdef GPG_NOCREATE
 static enum gpg_find_mode_e default_mode = GPG_FIND_MAIN;
 #else
 static enum gpg_find_mode_e default_mode = GPG_FIND_ORCREATE;
 #endif
 
 extern char zeros[65];
 
 /**
  * gcrypt implementation of the crypto interface.
  *
  * The same structure is used in both LQPrivKey and LQPubKey.
  *
  */
 struct gpg_store {
 	gcry_sexp_t k; ///< S-expression representing the current object type.
 	char fingerprint[LQ_FP_LEN]; ///< Fingerprint, used for LQPubKey.
 	char public_key[LQ_PUBKEY_LEN]; ///< Literal, uncompressed public key bytes. Used in LQPubKey.
 	char last_signature[LQ_SIGN_LEN]; ///< Stores the latest signature data generated by lq_privatekey_sign.
 	char last_data[LQ_DIGEST_LEN]; ///< Stores the last digest data that was signed using lq_privatekey_sign.
 };
 
 /// store gpg library version.
 static char *gpg_version = NULL;
 
 /// directory holding crypto keys.
 static int gpg_cfg_idx_dir;
 
 /// default digest id.
 static int gpg_passphrase_digest = GCRY_MD_SHA512;
 
 /// zero fp value
 const static char gpg_fingerprint_zero[LQ_FP_LEN];
 
 const static char gpg_default_store_key;
 
 static LQStore *gpg_key_store;
 
 /**
  * Verifies that installed gpg version is supported.
  * Sets up crypto keys dir and sets passphrase digest length.
  *
  * \todo replace path massage with cwalk lib
  */
 int lq_crypto_init(const char *base) {
 	int r;
 	int l = 0;
 	char *p;
 	char path[LQ_PATH_MAX];
 
 	lq_zero(path, LQ_PATH_MAX);
 	if (gpg_version == NULL) {
 		gpg_version = (char*)gcry_check_version(GPG_MIN_VERSION);
 		if (gpg_version == NULL) {
 			return debug_logerr(LLOG_ERROR, ERR_NOCRYPTO, "broken");
 		}
 		gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
 		if (!gcry_control (GCRYCTL_INITIALIZATION_FINISHED_P)) {
 			return debug_logerr(LLOG_ERROR, ERR_NOCRYPTO, "init gcrypt");
 		}
 	}
 	debug_x(LLOG_DEBUG, "gpg", "using gpg", 1, MORGEL_TYP_STR, 0, "version", gpg_version);
 
 	gpg_cfg_idx_dir = lq_config_register(LQ_TYP_STR, "CRYPTODIR");
 
 	p = path;
 	l = strlen(base);
 	lq_cpy(p, base, l);
 	if (path[l] != '/') {
 		path[l] = '/';
 		path[l+1] = 0;
 	}
 
 	r = lq_config_set(gpg_cfg_idx_dir, path);
 	if (r) {
 		return ERR_FAIL;
 	}
 	gpg_key_store = lq_store_new(path);
 	if (gpg_key_store == NULL) {
 		return ERR_STORE_AVAIL;
 	}
 
 	return ERR_OK;
 }
 
 size_t get_padsize(size_t insize, size_t blocksize) {
 	size_t c;
 	size_t l;
 	size_t m;
 
 	c = insize + 1;
 	l = c / blocksize;
 	m = c % blocksize;
 	if (m) {
 		l++;
 	}
 	return l * blocksize;
 }
 
 static void padb(char *data, size_t outsize, size_t insize) {
 	gcry_randomize(data + insize, outsize - insize, GCRY_STRONG_RANDOM);
 }
 
 static void pad(char *indata_raw, size_t outsize, const char *indata) { //std::string indata) {
 	int l;
 
 	strcpy(indata_raw, indata);
 	l = strlen(indata) + 1;
 	padb(indata_raw, outsize, l);
 }
 
 static int create_handle(gcry_cipher_hd_t *h, const char *key, const char *nonce) {
 	const char *p;
 	gcry_error_t e;
 
 	e = gcry_cipher_open(h, GCRY_CIPHER_CHACHA20, GCRY_CIPHER_MODE_POLY1305, GCRY_CIPHER_SECURE);
 	if (e) {
 		p = gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_FAIL, (char*)p);
 	}
 	e = gcry_cipher_setkey(*h, key, CHACHA20_KEY_LENGTH_BYTES);
 	if (e) {
 		return ERR_FAIL;
 	}
 	e = gcry_cipher_setiv(*h, nonce, CHACHA20_NONCE_LENGTH_BYTES);
 	if (e) {
 		return ERR_FAIL;
 	}
 	return ERR_OK;
 }
 
 
 static void free_handle(gcry_cipher_hd_t *h) {
 	gcry_cipher_close(*h);
 }
 
 // Puts mac in mac and newly generated mac key in mac_key
 // in is a buffer of in_len which must be cipher blocksize.
 // no data validation checking is done.
 static int create_mac(char *mac, char *mac_key, const char *in, size_t in_len) {
 	int r;
 	char *p;
 	size_t maclen;
 	gcry_mac_hd_t h;
 	gcry_error_t e;
 
 	r = gcry_mac_open(&h, GCRY_MAC_POLY1305, 0, NULL);
 	if (r) {
 		return r;
 	}
 
 	e = gcry_mac_setkey(h, mac_key, POLY1305_MAC_KEYLEN);
 	if (e) {
 		gcry_mac_close(h);
 		p = (char*)gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, p);
 	}
 
 	e = gcry_mac_write(h, in, in_len);
 	if (e) {
 		gcry_mac_close(h);
 		p = (char*)gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, p);
 	}
 
 	maclen = POLY1305_MAC_LEN;
 	e = gcry_mac_read(h, mac, &maclen);
 	if (e) {
 		gcry_mac_close(h);
 		p = (char*)gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, p);
 	}
 
 	gcry_mac_close(h);
 
 	if (maclen != POLY1305_MAC_LEN) {
 		p = (char*)gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, p);
 	}
 
 	return ERR_OK;
 }
 
 static int verify_mac(char *mac, char *mac_key, const char *in, size_t in_len) {
 	int r;
 	char *p;
 	size_t maclen;
 	gcry_mac_hd_t h;
 	gcry_error_t e;
 
 	r = gcry_mac_open(&h, GCRY_MAC_POLY1305, 0, NULL);
 	if (r) {
 		return r;
 	}
 
 	e = gcry_mac_setkey(h, mac_key, POLY1305_MAC_KEYLEN);
 	if (e) {
 		gcry_mac_close(h);
 		p = (char*)gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, p);
 	}
 
 	e = gcry_mac_write(h, in, in_len);
 	if (e) {
 		gcry_mac_close(h);
 		p = (char*)gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, p);
 	}
 
 	maclen = POLY1305_MAC_LEN;
 	e = gcry_mac_read(h, mac, &maclen);
 	if (e) {
 		gcry_mac_close(h);
 		p = (char*)gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, p);
 	}
 
 	e = gcry_mac_verify(h, mac, maclen);
 	if (e) {
 		gcry_mac_close(h);
 		p = (char*)gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, p);
 	}
 
 	gcry_mac_close(h);
 
 	if (maclen != POLY1305_MAC_LEN) {
 		p = (char*)gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, p);
 	}
 
 	return ERR_OK;
 }
 int encryptb (char *ciphertext, size_t ciphertext_len, const char *indata, size_t indata_len, const char *key, const char *nonce) {
 	const char *p;
 	int r;
 	gcry_cipher_hd_t h;
 	gcry_error_t e;
 	char indata_raw[ciphertext_len];
 
 	r = create_handle(&h, key, nonce);
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, "encrypt handle (bin)");
 	}
 	lq_cpy(indata_raw, indata, indata_len);
 	padb(indata_raw, ciphertext_len, indata_len);
 	e = gcry_cipher_encrypt(h, (unsigned char*)ciphertext, ciphertext_len, (const unsigned char*)indata_raw, ciphertext_len);
 	if (e) {
 		free_handle(&h);
 		p = gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, (char*)p);
 	}
 
 	free_handle(&h);
 
 
 	return ERR_OK;
 }
 
 int encrypt(char *ciphertext, size_t ciphertext_len, const char *indata, const char *key, const char *nonce) {
 	char *p;
 	int r;
 	gcry_cipher_hd_t h;
 	gcry_error_t e;
 	char indata_raw[ciphertext_len];
 
 	r = create_handle(&h, key, nonce);
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, "encrypt handle (str)");
 	}
 
 	pad(indata_raw, ciphertext_len, indata);
 	e = gcry_cipher_encrypt(h, (unsigned char*)ciphertext, ciphertext_len, (const unsigned char*)indata_raw, ciphertext_len);
 	if (e) {
 		free_handle(&h);
 		p = (char*)gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, p);
 	}
 
 	free_handle(&h);
 
 	return ERR_OK;
 }
 
 int decryptb(char *outdata, const char *ciphertext, size_t ciphertext_len, const char *key, const char *nonce) {
 	char *p;
 	int r;
 	gcry_cipher_hd_t h;
 	gcry_error_t e;
 
 	r = create_handle(&h, key, nonce);
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, "decrypt handle (bin)");
 	}
 
 	e = gcry_cipher_decrypt(h, outdata, ciphertext_len, ciphertext, ciphertext_len);
 	if (e) {
 		free_handle(&h);
 		p = (char*)gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, p);
 	}
 
 	free_handle(&h);
 
 	return ERR_OK;
 }
 
 int decrypt(char *outdata, const char *ciphertext, size_t ciphertext_len, const char *key, const char *nonce) {
 	char *p;
 	int r;
 	gcry_cipher_hd_t h;
 	gcry_error_t e;
 
 	r = create_handle(&h, key, nonce);
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, "decrypt handle (str)");
 	}
 
 	e = gcry_cipher_decrypt(h, outdata, ciphertext_len, ciphertext, ciphertext_len);
 	if (e) {
 		free_handle(&h);
 		p = (char*)gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, p);
 	}
 
 	free_handle(&h);
 
 	return ERR_OK;
 }
 
 
 // DIGEST SECTION
 
 /// Calculate a digest according to the specified algo.
 static int calculate_digest_algo(const char *in, size_t in_len, char *out, enum gcry_md_algos algo) {
 	gcry_error_t e;
 	gcry_md_hd_t h;
 	unsigned char *v;
 	static unsigned int digest_len;
 
 	if (algo == GCRY_MD_NONE) {
 		algo = GCRY_MD_SHA512;
 	}
 
 	e = gcry_md_open(&h, algo, GCRY_MD_FLAG_SECURE);
 	if (e) {
 		return ERR_ENCODING;
 	}
 	e = gcry_md_enable(h, algo);
 	if (e) {
 		return ERR_COMPAT;
 	}
 	digest_len = gcry_md_get_algo_dlen(algo);
 
 	gcry_md_write(h, in, in_len);
 	v = gcry_md_read(h, 0);
 	lq_cpy(out, v, digest_len);
 	gcry_md_close(h);
 	return ERR_OK;
 }
 
 /// Calculate digest using the default hashing algorithm (SHA256)
 /// using the gcrypt library.
 int lq_digest(const char *in, size_t in_len, char *out) {
 	return calculate_digest_algo(in, in_len, out, GCRY_MD_NONE);
 }
 
 
 /// Apply public key to the gpg_store struct.
 static int key_apply_public(struct gpg_store *gpg) {
 	char *p;
 	size_t c;
 	gcry_sexp_t one;
 	gcry_sexp_t two;
 
 	one = gcry_sexp_find_token(gpg->k, "public-key", 10);
 	if (one == NULL) {
 		return debug_logerr(LLOG_ERROR, ERR_KEYFAIL, "sexp pubkey");
 	}
 	two = gcry_sexp_find_token(one, "q", 1);
 	if (two == NULL) {
 		gcry_sexp_release(one);
 		return debug_logerr(LLOG_ERROR, ERR_KEYFAIL, "sexp q");
 	}
 	c = LQ_PUBKEY_LEN;
 	p = (char*)gcry_sexp_nth_data(two, 1, &c);
 	if (p == NULL) {
 		gcry_sexp_release(two);
 		gcry_sexp_release(one);
 		return debug_logerr(LLOG_ERROR, ERR_KEYFAIL, "sexp first data");
 	}
 
 	lq_cpy(gpg->public_key, p, LQ_PUBKEY_LEN);
 	gcry_sexp_release(two);
 	gcry_sexp_release(one);
 	p = (char*)gcry_pk_get_keygrip(gpg->k, (unsigned char*)gpg->fingerprint);
 	if (p == NULL) {
 		return debug_logerr(LLOG_ERROR, ERR_KEYFAIL, "pubkey fingerprint");
 	}
 
 	return ERR_OK;
 }
 
 /// Create a new gcrypt keypair.
 static int key_create(struct gpg_store *gpg) {
 	int r;
 	const char *p;
 	const char *sexp_quick = "(genkey(ecc(flags eddsa)(curve Ed25519)))";
 	gcry_sexp_t in;
 	gcry_error_t e;
 
 	// Set up parameters for key creation.
 	e = gcry_sexp_new(&in, (const void*)sexp_quick, strlen(sexp_quick), 0);
 	if (e) {
 		p = gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_KEYFAIL, (char*)p);
 	}
 
 	// Generate a new key with the given parameters.
 	e = gcry_pk_genkey(&gpg->k, in);
 	if (e) {
 		gcry_sexp_release(in);
 		p = gcry_strerror(e);
 		return debug_logerr(LLOG_ERROR, ERR_KEYFAIL, (char*)p);
 	}
 	gcry_sexp_release(in);
 
 	// Apply the public part of the key to the underlying key structure.
 	r = key_apply_public(gpg);
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_KEYFAIL, "private create apply public");
 	}
 
 	return ERR_OK;
 }
 
 static LQStore *key_store_get() {
 	return gpg_key_store;
 }
 
 /**
  * \todo consistent endianness for key length in persistent storage (fwrite)
  * \todo doc must have enough in path for path + fingerprint hex
  * \todo check capacity in buffer for both ciphertext, nonce and mac.
  */
 static int key_create_store(struct gpg_store *gpg, const char *passphrase, size_t passphrase_len) {
 	char *p;
 	int r;
 	int kl;
 	char v[LQ_CRYPTO_BUFLEN];
 	int l;
 	size_t c;
 	size_t m;
 	LQStore *store;
 	LQPubKey *pubk;
 	char nonce[CHACHA20_NONCE_LENGTH_BYTES];
 	char buf_key[LQ_STORE_KEY_MAX];
 	char buf_val[LQ_STORE_VAL_MAX];
 	char ciphertext[LQ_CRYPTO_BUFLEN];
 	char passphrase_hash[LQ_DIGEST_LEN];
 	char mac[POLY1305_MAC_LEN];
 
 	// Initialize to assist debugging.
 	lq_zero(buf_key, LQ_STORE_KEY_MAX);
 	lq_zero(buf_val, LQ_STORE_VAL_MAX);
 
 	// Create the private key and corresponding public key.
 	r = key_create(gpg);
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_KEYFAIL, "key create");
 	}
 	
 	// Export the S-expression to a text buffer for saving, canonical formatting
 	kl = gcry_sexp_sprint(gpg->k, GCRYSEXP_FMT_CANON, NULL, 0);
 	m = (size_t)kl + 1;
 	p = (char*)v + sizeof(int);
 	c = 0;
 	kl = gcry_sexp_sprint(gpg->k, GCRYSEXP_FMT_CANON, p, LQ_CRYPTO_BUFLEN - m);
 	m -= (size_t)(kl + 1);
 	c += kl;
 	lq_cpy(v, &c, sizeof(int));
 
 	// Pad the contents up to the blocksize boundary
 	m = c;
 	c = get_padsize(m, LQ_CRYPTO_BLOCKSIZE);
 
 	// Hash the encryption key to the expected length.
 	r = calculate_digest_algo(passphrase, passphrase_len, passphrase_hash, gpg_passphrase_digest);
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_DIGEST, "passphrase hash");
 	}
 
 	// Encrypt the payload with the passphrase and nonce.
 	gcry_create_nonce(nonce, CHACHA20_NONCE_LENGTH_BYTES);
 	r = encryptb(ciphertext, c, v, m+sizeof(int), passphrase_hash, nonce);
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_KEY_LOCK, "encrypt private key");
 	}
 
 	c += CHACHA20_NONCE_LENGTH_BYTES;
 	r = create_mac(mac, passphrase_hash + CHACHA20_KEY_LENGTH_BYTES, v, m+sizeof(int));
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, "mac generation fail");
 		return r;
 	}
 	lq_cpy(ciphertext + c, mac, POLY1305_MAC_LEN);
 
 	// Export the key (fingerprint) and value (ciphertext) to put in the store.
 	// (We don't need the inner private key pointer anymore, so we re-use it.)
 	pubk = lq_publickey_new(gpg->public_key);
 	if (pubk == NULL) {
 		return debug_logerr(LLOG_ERROR, ERR_KEYFAIL, "publickey");
 	}
 	gpg = (struct gpg_store*)pubk->impl;
 	lq_cpy(buf_key, gpg->fingerprint, LQ_FP_LEN);
 	lq_cpy(buf_val, nonce, CHACHA20_NONCE_LENGTH_BYTES);
 	lq_cpy(buf_val + CHACHA20_NONCE_LENGTH_BYTES, ciphertext, c);
 	lq_cpy(buf_val + CHACHA20_NONCE_LENGTH_BYTES + c, mac, POLY1305_MAC_LEN);
 	lq_publickey_free(pubk);
 
 	// Retrieve the store.
 	store = key_store_get();
 	if (store == NULL) {
 		return debug_logerr(LLOG_ERROR, ERR_KEYFILE, "create store");
 	}
 
 	// Write the ciphertext to the store.	
 	l = c + POLY1305_MAC_LEN;
 	c = LQ_FP_LEN;
 	r = store->put(LQ_CONTENT_KEY, store, buf_key, &c, buf_val, l);
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_KEYFILE, "put key in store");
 	}
 
 	// Check if a main key already exists in the store.
 	// If not, set this one as main.
 	*buf_key = gpg_default_store_key;
 	c = LQ_STORE_VAL_MAX; 
 	r = store->get(LQ_CONTENT_KEY, store, buf_key, 1, buf_val, &c);
 	if (r) {
 		if (r != ERR_NOENT) {
 			debug(LLOG_ERROR, "crypto.gcrypt", "no default");
 			return debug_logerr(LLOG_ERROR, ERR_KEYFILE, "default key");
 		}
 		c = 1;
 		r = store->put(LQ_CONTENT_KEY, store, buf_key, &c, buf_val, l);
 		if (r) {
 			debug(LLOG_ERROR, "crypto.gcrypt", "fail put default");
 			return debug_logerr(LLOG_ERROR, ERR_KEYFILE, "write default key");
 		}
 	}
 
 	return ERR_OK;
 }
 
 /// Create a new keypair, encrypted with given passphrase.
 static LQPrivKey* privatekey_alloc(const char *passphrase, size_t passphrase_len) {
 	int r;
 	LQPrivKey *o;
 	struct gpg_store *gpg;
 
 	// Allocate private key structures.
 	o = lq_alloc(sizeof(LQPrivKey));
 	if (o == NULL) {
 		return NULL;
 	}
 	gpg = lq_alloc(sizeof(struct gpg_store));
 	if (gpg == NULL) {
 		lq_free(o);
 		return NULL;
 	}
 
 	// Create the underlying private key.
 	r = key_create_store(gpg, passphrase, passphrase_len);
 	if (r) {
 		lq_free(gpg);
 		lq_free(o);
 		return NULL;
 	}
 
 	// Populate the internal key structure.
 	o->impl = (void*)gpg;
 	o->key_typ = GPG_KEY_TYP;
 	o->key_state = LQ_KEY_INIT;
 
 	// No cleanup = caller must free it.
 	debug_x(LLOG_INFO, "gpg", "created new private key", 1, MORGEL_TYP_BIN, LQ_FP_LEN, "fingerprint", gpg->fingerprint);
 
 	return o;
 }
 
 
 /// Implements the interface to create a new private key.
 LQPrivKey* lq_privatekey_new(const char *passphrase, size_t passphrase_len) {
 	int r;
 	LQPrivKey *o;
 	if (passphrase == NULL) {
 		return NULL;
 	}
 
 	o = privatekey_alloc(passphrase, passphrase_len);
 	if (o == NULL) {
 		return NULL;
 	}
 	r = lq_privatekey_lock(o, passphrase, passphrase_len);
 	if (r) {
 		return NULL;
 	}
 	return o;
 }
 
 /// Parse data from buffer as S-expression text representing a key.
 static int key_from_data(gcry_sexp_t *key, const char *indata, size_t indata_len) {
 	gcry_error_t e;
 
 	e = gcry_sexp_new(key, indata, indata_len, 0);
 	if (e != GPG_ERR_NO_ERROR) {
 		return debug_logerr(LLOG_ERROR, ERR_COMPAT, "not key data");
 	}
 	return ERR_OK;
 }
 
 static int check_ciphertext(const char *buf, size_t buf_len) {
 	return buf_len % (LQ_CRYPTO_BLOCKSIZE + CHACHA20_NONCE_LENGTH_BYTES + POLY1305_MAC_LEN);
 }
 
 /// Load a private key from the store's crypto partition.
 static int key_from_store(struct gpg_store *gpg, const char *passphrase, size_t passphrase_len) {
 	char *nonce;
 	char *p;
 	int r;
 	LQStore *store;
 	char inkey[LQ_FP_LEN];
 	size_t inkey_len;
 	char out[LQ_CRYPTO_BUFLEN];
 	char in[LQ_CRYPTO_BUFLEN];
 	size_t in_len;
 	size_t out_len;
 	char passphrase_hash[LQ_DIGEST_LEN];
 
 	// Instantiate the store.
 	store = key_store_get();
 
 	// If a valid fingerprint is found in the gpg structure,
 	// retrieve the key matching that fingerprint.
 	// Otherwise, retrieve the main key.
 	// Or fail if none of them can be found.
 	inkey_len = LQ_FP_LEN;
 	in_len = LQ_CRYPTO_BUFLEN;
 	if (lq_cmp(gpg->fingerprint, gpg_fingerprint_zero, LQ_FP_LEN)) {
 		lq_cpy(inkey, gpg->fingerprint, LQ_FP_LEN);	
 	} else {
 		*inkey = gpg_default_store_key;
 		inkey_len = 1;
 	}
 	r = store->get(LQ_CONTENT_KEY, store, inkey, inkey_len, in, &in_len);
 	if (r) {
 		return ERR_NOENT;
 	}
 
 	r = check_ciphertext(in, in_len);
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_CIPHER, "incorrect ciphertext");
 	}
 
 	// Hash the encryption key to the expected length.
 	r = calculate_digest_algo(passphrase, passphrase_len, passphrase_hash, gpg_passphrase_digest);
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_DIGEST, "passphrase hash");
 	}
 
 	// Decrypt the private key data from the store
 	// with the provided passphrase and the extracted nonce.
 	nonce = in;
 	p = (char*)in + CHACHA20_NONCE_LENGTH_BYTES;
 	in_len -= CHACHA20_NONCE_LENGTH_BYTES;
 	r = decryptb(out, p, in_len - POLY1305_MAC_LEN, passphrase_hash, nonce);
 	if (r) {
 		return ERR_KEY_UNLOCK;
 	}
 
 	r = verify_mac(p + in_len - POLY1305_MAC_LEN, passphrase_hash + CHACHA20_KEY_LENGTH_BYTES, out, in_len - POLY1305_MAC_LEN);
 	if (r) {
 		return ERR_KEY_UNLOCK;
 	}
 
 	// Attempt to parse and instantiate the key from the decrypted data.
 	out_len = (size_t)(*((int*)out));
 	p = (char*)(out+sizeof(int));
 	r = key_from_data(&gpg->k, p, out_len);
 	if (r) {
 		return ERR_KEYFAIL;
 	}
 
 	return ERR_OK;
 }
 
 static int gpg_key_load(struct gpg_store *gpg, const char *passphrase, size_t passphrase_len, enum gpg_find_mode_e mode, const void *criteria) {
 	int r;
 
 	switch(mode) {
 		case GPG_FIND_MAIN:
 			r = key_from_store(gpg, passphrase, passphrase_len);
 			if (r) {
 				return debug_logerr(LLOG_WARNING, ERR_KEYFILE, "default key not found");
 			}
 			break;
 		case GPG_FIND_ORCREATE:
 			r = key_from_store(gpg, passphrase, passphrase_len);
 			if (r == ERR_OK) {
 				break;
 			}
 			if (r != ERR_NOENT) {
 				debug(LLOG_INFO, "gpg", "default decrypt failed");
 				break;
 			}
 			// if no key could be loaded, attempt to create one.
 			if (!lq_cmp(gpg_fingerprint_zero, gpg->fingerprint, LQ_FP_LEN)) {
 				debug(LLOG_DEBUG, "gpg", "default private key not found, attempting create new");
 				r = key_create_store(gpg, passphrase, passphrase_len);
 				if (r) {
 					return debug_logerr(LLOG_WARNING, ERR_KEYFILE, "create key when no default found");
 				}
 			}
 			break;
 		case GPG_FIND_FINGERPRINT:
 			r = key_from_store(gpg, passphrase, passphrase_len);
 			if (r) {
 				return debug_logerr(LLOG_WARNING, ERR_KEYFILE, "fingerprint key not found");
 			}
 			break;
 		default:
 			return debug_logerr(LLOG_WARNING, ERR_FAIL, NULL);
 	}
 
 	r = key_apply_public(gpg);
 	if (r) {
 		return debug_logerr(LLOG_ERROR, ERR_KEYFAIL, "apply public key");
 	}
 	debug_x(LLOG_INFO, "gpg", "loaded private key", 1, MORGEL_TYP_BIN, LQ_FP_LEN, "fingerprint", gpg->fingerprint);
 	
 	return ERR_OK;
 }
 
 
 /// Implements the interface to load a private key from storage.
 LQPrivKey* lq_privatekey_load(const char *passphrase, size_t passphrase_len, const char *fingerprint) {
 	LQPrivKey *pk;
 	enum gpg_find_mode_e m;
 	struct gpg_store *gpg;
 	int r;
 	
 	pk = lq_alloc(sizeof(LQPrivKey));
 	if (pk == NULL) {
 		debug_logerr(LLOG_ERROR, ERR_KEYFAIL, "allocate object");
 		return NULL;
 	}
 	pk->impl = (struct gpg_store*)lq_alloc(sizeof(struct gpg_store));
 	if (pk->impl == NULL) {
 		lq_free(pk);
 		debug_logerr(LLOG_ERROR, ERR_KEYFAIL, "allocate internal structure");
 		return NULL;
 	}
 	lq_zero(pk->impl, sizeof(struct gpg_store));
 	gpg = (struct gpg_store*)pk->impl;
 	m = default_mode;
 	if (fingerprint != NULL) {
 		lq_cpy(gpg->fingerprint, fingerprint, LQ_FP_LEN);
 		m = GPG_FIND_FINGERPRINT;
 	}
 	r = gpg_key_load(gpg, passphrase, passphrase_len, m, NULL);
 	if (r) {
 		lq_free(pk->impl);
 		lq_free(pk);
 		debug_logerr(LLOG_ERROR, ERR_KEYFAIL, "key load fail");
 		return NULL;	
 	}
 	pk->key_typ = GPG_KEY_TYP;
 	pk->key_state = LQ_KEY_INIT;
 
 	return pk;
 }
 
 size_t lq_publickey_bytes(LQPubKey *pubk, char **out) {
 	struct gpg_store *gpg;
 
 	gpg = (struct gpg_store*)pubk->impl;
 	*out = gpg->public_key;
 	return LQ_PUBKEY_LEN;
 }
 
 int lq_privatekey_lock(LQPrivKey *pk, const char *passphrase, size_t passphrase_len) {
 	if (pk == NULL) {
 		return ERR_INIT;
 	}
 	if ((pk->key_state & LQ_KEY_LOCK) > 0) {
 		return ERR_NOOP;
 	}
 	pk->key_state |= LQ_KEY_LOCK;
 	return ERR_OK;
 }
 
 int lq_privatekey_unlock(LQPrivKey *pk, const char *passphrase, size_t passphrase_len) {
 	char b;
 
 	if (pk == NULL) {
 		return ERR_INIT;
 	}
 	if ((pk->key_state & LQ_KEY_LOCK) == 0) {
 		return ERR_NOOP;
 	}
 	b = LQ_KEY_LOCK;
 	pk->key_state &= ~b;
 	return ERR_OK;
 }
 
 // SIGNATURE SECTION
 //
 //int sign_with(struct gpg_store *gpg, char *data, size_t data_len, const char *passphrase, const char *fingerprint) {
 //	int r;
 //	size_t c;
 //	gcry_sexp_t pnt;
 //	gcry_sexp_t msg;
 //	gcry_sexp_t sig;
 //	gcry_error_t e;
 //	char *p;
 //
 //
 //	if (fingerprint == NULL) {
 //		r = gpg_key_load(gpg, passphrase, KEE_GPG_FIND_MAIN, NULL);
 //	} else {
 //		r = gpg_key_load(gpg, passphrase, KEE_GPG_FIND_FINGERPRINT, fingerprint);
 //	}
 //	if (r) {
 //		return 1;
 //	}
 //		 
 //	c = 0;
 //	e = gcry_sexp_build(&msg, &c, "(data(flags eddsa)(hash-algo sha512)(value %b))", 64, gpg->last_data);
 //	if (e != GPG_ERR_NO_ERROR) {
 //		return 1;
 //	}
 //}
 
 static int sign(struct gpg_store *gpg, const char *data, size_t data_len, const char *salt) {
 	int r;
 	size_t c;
 	char *p;
 	gcry_sexp_t pnt;
 	gcry_sexp_t msg;
 	gcry_sexp_t sig;
 	gcry_error_t e;
 
 	lq_zero(&e, sizeof(gcry_error_t));
 	r = calculate_digest_algo(data, data_len, gpg->last_data, GCRY_MD_SHA512);
 	if (r) {
 		return 1;
 	}
 
 	c = 0;
 	e = gcry_sexp_build(&msg, &c, "(data(flags eddsa)(hash-algo sha512)(value %b))", 64, gpg->last_data);
 	if (e != GPG_ERR_NO_ERROR) {
 		return 1;
 	}
 
 	e = gcry_pk_sign(&sig, msg, gpg->k);
 	if (e != GPG_ERR_NO_ERROR) {
 		gcry_sexp_release(msg);
 		return 1;
 	}
 
 	// retrieve r and write it
 	pnt = NULL;
 	pnt = gcry_sexp_find_token(sig, "r", 1);
 	if (pnt == NULL) {
 		gcry_sexp_release(sig);
 		gcry_sexp_release(msg);
 		return ERR_FAIL;
 	}
 	c = LQ_POINT_LEN;
 	p = (char*)gcry_sexp_nth_data(pnt, 1, &c);
 	if (p == NULL) {
 		gcry_sexp_release(pnt);
 		gcry_sexp_release(sig);
 		gcry_sexp_release(msg);
 		return ERR_SIGVALID;
 	}
 	lq_cpy(gpg->last_signature, p, c);
 
 	// retrieve s and write it
 	gcry_sexp_release(pnt);
 	pnt = NULL;
 	pnt = gcry_sexp_find_token(sig, "s", 1);
 	if (pnt == NULL) {
 		gcry_sexp_release(sig);
 		gcry_sexp_release(msg);
 		return ERR_FAIL;
 	}
 	c = LQ_POINT_LEN;
 	p = (char*)gcry_sexp_nth_data(pnt, 1, &c);
 	if (p == NULL) {
 		gcry_sexp_release(pnt);
 		gcry_sexp_release(sig);
 		gcry_sexp_release(msg);
 		return ERR_SIGVALID;
 	}
 	lq_cpy(gpg->last_signature + LQ_POINT_LEN, p, c);
 	gcry_sexp_release(pnt);
 	gcry_sexp_release(sig);
 	gcry_sexp_release(msg);
 
 	return ERR_OK;
 }
 
 LQSig* lq_privatekey_sign(LQPrivKey *pk, const char *data, size_t data_len, const char *salt) {
 	int r;
 	struct gpg_store *gpg;
 	LQSig *sig;
 
 	if ((pk->key_state & LQ_KEY_LOCK) > 0) {
 		debug_logerr(LLOG_INFO, ERR_KEY_LOCK, "key locked");
 		return NULL;
 	}
 
 	gpg = (struct gpg_store*)pk->impl;
 
 	r = sign(gpg, data, data_len, salt);
 	if (r != ERR_OK) {
 		return NULL;
 	}
 
 	sig = lq_alloc(sizeof(LQSig));
 	sig->pubkey = lq_publickey_from_privatekey(pk);
 	if (sig->pubkey == NULL) {
 		lq_signature_free(sig);
 		return NULL;
 	}
 	sig->impl = lq_alloc(LQ_SIGN_LEN);
 	lq_cpy(sig->impl, gpg->last_signature, LQ_SIGN_LEN);
 	return sig;
 }
 
 LQSig* lq_signature_from_bytes(const char *sig_data, size_t sig_len, LQPubKey *pubkey) {
 	size_t r;
 	LQSig *sig;
 	char *pubkey_out;
 
 	if (!lq_cmp(sig_data, zeros, LQ_SIGN_LEN)) {
 		return NULL;
 	}
 
 	sig = lq_alloc(sizeof(LQSig));
 	lq_zero(sig, sizeof(LQSig));
 	sig->impl = lq_alloc(LQ_SIGN_LEN);
 	lq_cpy(sig->impl, sig_data, LQ_SIGN_LEN);
 
 	if (pubkey != NULL) {
 		r = lq_publickey_bytes(pubkey, &pubkey_out);
 		if (!r) {
 			return NULL;
 		}
 		sig->pubkey = lq_publickey_new(pubkey_out);
 	}
 	return sig;
 }
 
 size_t lq_signature_bytes(LQSig *sig, char **out) {
 	*out = sig->impl;
 	return LQ_SIGN_LEN;
 }
 
 int lq_signature_verify(LQSig *sig, const char *data, size_t data_len) {
 	const char *p;
 	int r;
 	size_t c;
 	gcry_mpi_t sig_r;
 	gcry_mpi_t sig_s;
 	gcry_error_t e;
 	gcry_sexp_t sigx;
 	gcry_sexp_t msgx;
 	gcry_sexp_t pubkey;
 	struct gpg_store *gpg;
 	char digest[LQ_DIGEST_LEN];
 
 	if (sig->pubkey == NULL) {
 		return ERR_NOENT;
 	}
 
 	gpg = (struct gpg_store*)sig->pubkey->impl;
 	c = 0;
 	e = gcry_sexp_build(&pubkey, &c, "(key-data(public-key(ecc(curve Ed25519)(q %b))))", LQ_PUBKEY_LEN, gpg->public_key);
 	if (e != GPG_ERR_NO_ERROR) {
 		return ERR_KEYFAIL;
 	}
 
 	c = 0;
 	e = gcry_mpi_scan(&sig_r, GCRYMPI_FMT_STD, sig->impl, LQ_POINT_LEN, &c);
 	if (e != GPG_ERR_NO_ERROR) {
 		p = gcry_strerror(e);
 		gcry_sexp_release(pubkey);
 		return debug_logerr(LLOG_INFO, ERR_KEYFAIL, (char*)p);
 	}
 	if (c != 32) {
 		p = gcry_strerror(e);
 		gcry_mpi_release(sig_r);
 		gcry_sexp_release(pubkey);
 		return debug_logerr(LLOG_INFO, ERR_KEYFAIL, (char*)p);
 	}
 
 	c = 0;
 	e = gcry_mpi_scan(&sig_s, GCRYMPI_FMT_STD, sig->impl + LQ_POINT_LEN, LQ_POINT_LEN, &c);
 	if (e != GPG_ERR_NO_ERROR) {
 		p = gcry_strerror(e);
 		gcry_mpi_release(sig_r);
 		gcry_sexp_release(pubkey);
 		return debug_logerr(LLOG_INFO, ERR_KEYFAIL, (char*)p);
 	}
 	if (c != 32) {
 		p = gcry_strerror(e);
 		gcry_mpi_release(sig_s);
 		gcry_mpi_release(sig_r);
 		gcry_sexp_release(pubkey);
 		return debug_logerr(LLOG_INFO, ERR_KEYFAIL, (char*)p);
 	}
 
 	c = 0;
 	e = gcry_sexp_build(&sigx, &c, "(sig-val(eddsa(r %m)(s %m)))", sig_r, sig_s);
 	if (e != GPG_ERR_NO_ERROR) {
 		p = gcry_strerror(e);
 		gcry_mpi_release(sig_s);
 		gcry_mpi_release(sig_r);
 		gcry_sexp_release(pubkey);
 		return debug_logerr(LLOG_INFO, ERR_SIGFAIL, (char*)p);
 	}
 	gcry_mpi_release(sig_s);
 	gcry_mpi_release(sig_r);
 
 	r = calculate_digest_algo(data, data_len, digest, GCRY_MD_SHA512);
 	if (r) {
 		p = gcry_strerror(e);
 		gcry_sexp_release(sigx);
 		gcry_sexp_release(pubkey);
 		return debug_logerr(LLOG_INFO, ERR_DIGEST, (char*)p);
 	}
 
 	c = 0;
 	e = gcry_sexp_build(&msgx, &c, "(data(flags eddsa)(hash-algo sha512)(value %b))", LQ_DIGEST_LEN, digest);
 	if (e != GPG_ERR_NO_ERROR) {
 		p = gcry_strerror(e);
 		gcry_sexp_release(sigx);
 		gcry_sexp_release(pubkey);
 		return debug_logerr(LLOG_INFO, ERR_DIGEST, (char*)p);
 	}
 
 	e = gcry_pk_verify(sigx, msgx, pubkey);
 	if (e != GPG_ERR_NO_ERROR) {
 		p = gcry_strerror(e);
 		gcry_sexp_release(msgx);
 		gcry_sexp_release(sigx);
 		gcry_sexp_release(pubkey);
 		return debug_logerr(LLOG_INFO, ERR_SIGVALID, (char*)p);
 	}
 
 	gcry_sexp_release(msgx);
 	gcry_sexp_release(sigx);
 	gcry_sexp_release(pubkey);
 
 	return ERR_OK;
 }
 
 void lq_privatekey_free(LQPrivKey *pk) {
 	struct gpg_store *gpg;
 
 	gpg = (struct gpg_store*)pk->impl;
 	gcry_sexp_release(gpg->k);
 	lq_free(pk->impl);
 	lq_free(pk);
 }
 
 void lq_publickey_free(LQPubKey *pubk) {
 	struct gpg_store *gpg;
 
 	gpg = (struct gpg_store*)pubk->impl;
 	gcry_sexp_release(gpg->k);
 	lq_free(pubk->impl);
 	lq_free(pubk);
 }
 
 void lq_signature_free(LQSig *sig) {
 	if (sig->pubkey != NULL) {
 		lq_publickey_free(sig->pubkey);
 	}
 	if (sig->impl != NULL) {
 		lq_free(sig->impl);
 	}
 	lq_free(sig);
 }
 
 LQPubKey* lq_publickey_from_privatekey(LQPrivKey *pk) {
 	struct gpg_store *gpg;
 	LQPubKey *pubk;
 
 	gpg = (struct gpg_store*)pk->impl;
 	pubk = lq_publickey_new(gpg->public_key);
 
 	return pubk;
 }
 
 LQPubKey* lq_publickey_new(const char *full) {
 	const char *p;
 	const char *r;
 	gcry_error_t e;
 	size_t c;
 	LQPubKey *pubk;
 	struct gpg_store *gpg;
 
 	gpg = lq_alloc(sizeof(struct gpg_store));
 	lq_zero(gpg, sizeof(struct gpg_store));
 	lq_cpy(gpg->public_key, full, LQ_PUBKEY_LEN);
 
 	pubk = lq_alloc(sizeof(LQPubKey));
 	lq_zero(pubk, sizeof(LQPubKey));
 
 	c = 0;
 	e = gcry_sexp_build(&gpg->k, &c, "(key-data(public-key(ecc(curve Ed25519)(q %b))))", LQ_PUBKEY_LEN, full);
 	if (e != GPG_ERR_NO_ERROR) {
 		p = gcry_strerror(e);
 		debug_logerr(LLOG_DEBUG, ERR_KEYFAIL, (char*)p);
 		return NULL;
 	}
 
 	r = (char*)gcry_pk_get_keygrip(gpg->k, (unsigned char*)gpg->fingerprint);
 	if (r == NULL) {
 		debug_logerr(LLOG_ERROR, ERR_KEYFAIL, "fingerprint fail");
 		return NULL;
 	}
 
 	pubk->impl = (void*)gpg;
 	pubk->key_typ = GPG_KEY_TYP;
 	pubk->pk = NULL;
 
 	return pubk;
 }
 
 int lq_publickey_match(LQPubKey *left, LQPubKey *right) {
 	struct gpg_store *lstore;
 	struct gpg_store *rstore;
 
 	if (left == NULL) {
 		return ERR_NONSENSE;
 	}
 	if (right == NULL) {
 		return ERR_NONSENSE;
 	}
 	lstore = (struct gpg_store*)left->impl;
 	rstore = (struct gpg_store*)right->impl;
 
 	if (lq_cmp(lstore->fingerprint, rstore->fingerprint, LQ_PUBKEY_LEN)) {
 		return ERR_FAIL;
 	}
 
 	return ERR_OK;
 }
 
 size_t lq_publickey_fingerprint(LQPubKey* pubk, char **out) {
 	struct gpg_store *gpg;
 
 	gpg = (struct gpg_store*)pubk->impl;
 	*out = gpg->fingerprint;
 	return LQ_FP_LEN;
 }
 
 void lq_crypto_free() {
 	//lq_store_free((void*)gpg_key_store);
 	gpg_key_store->free(gpg_key_store);
 	gpg_key_store = NULL;
 	gpg_version = NULL;
 }
 
 #endif