From 626a8d8d3df8880991684d6d1a06b82f6685b51a Mon Sep 17 00:00:00 2001 From: vnugent Date: Sun, 28 Jan 2024 19:23:18 -0500 Subject: initial commit --- src/noscrypt.c | 865 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 865 insertions(+) create mode 100644 src/noscrypt.c (limited to 'src/noscrypt.c') diff --git a/src/noscrypt.c b/src/noscrypt.c new file mode 100644 index 0000000..6ef273f --- /dev/null +++ b/src/noscrypt.c @@ -0,0 +1,865 @@ +/* +* Copyright (c) 2024 Vaughn Nugent +* +* Library: noscrypt +* Package: noscrypt +* File: noscrypt.c +* +* noscrypt is free software: you can redistribute it and/or modify +* it under the terms of the GNU General Public License as published +* by the Free Software Foundation, either version 2 of the License, +* or (at your option) any later version. +* +* noscrypt is distributed in the hope that it will be useful, +* but WITHOUT ANY WARRANTY; without even the implied warranty of +* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +* General Public License for more details. +* +* You should have received a copy of the GNU General Public License +* along with noscrypt. If not, see http://www.gnu.org/licenses/. +*/ + +#include "noscrypt.h" + +#include +#include + +//Setup mbedtls +#include +#include +#include +#include +#include + +#define CHACHA_NONCE_SIZE 12 //Size of 12 is set by the cipher spec +#define CHACHA_KEY_SIZE 32 +#define HMAC_KEY_SIZE 32 + +/* +* Local macro for secure zero buffer fill +*/ +#define ZERO_FILL(x, size) mbedtls_platform_zeroize(x, size) + +//Include string for memmove +#include +#define MEMMOV(dst, src, size) memmove(dst, src, size) + +struct nc_expand_keys { + uint8_t chacha_key[CHACHA_KEY_SIZE]; + uint8_t chacha_nonce[CHACHA_NONCE_SIZE]; + uint8_t hamc_key[HMAC_KEY_SIZE]; +}; + +struct shared_secret { + uint8_t value[NC_SHARED_SEC_SIZE]; +}; + +struct conversation_key { + uint8_t value[NC_CONV_KEY_SIZE]; +}; + +struct message_key { + uint8_t value[NC_MESSAGE_KEY_SIZE]; +}; + +/* +* Internal helper functions to do common structure conversions +*/ + +static inline int _convertToXonly(const NCContext* ctx, const NCPublicKey* compressedPubKey, secp256k1_xonly_pubkey* xonly) +{ + DEBUG_ASSERT2(ctx != NULL, "Expected valid context") + DEBUG_ASSERT2(compressedPubKey != NULL, "Expected a valid public 32byte key structure") + DEBUG_ASSERT2(xonly != NULL, "Expected valid X-only secp256k1 public key structure ") + + //Parse the public key into the x-only structure + return secp256k1_xonly_pubkey_parse(ctx->secpCtx, xonly, compressedPubKey->key); +} + +static int _convertToPubKey(const NCContext* ctx, const NCPublicKey* compressedPubKey, secp256k1_pubkey* pubKey) +{ + int result; + uint8_t compressed[NC_PUBKEY_SIZE + 1]; + + DEBUG_ASSERT2(ctx != NULL, "Expected valid context") + DEBUG_ASSERT2(compressedPubKey != NULL, "Expected a valid public 32byte key structure") + DEBUG_ASSERT2(pubKey != NULL, "Expected valid secp256k1 public key structure") + + //Set the first byte to 0x02 to indicate a compressed public key + compressed[0] = BIP340_PUBKEY_HEADER_BYTE; + + //Copy the compressed public key data into a new buffer (offset by 1 to store the header byte) + MEMMOV((compressed + 1), compressedPubKey->key, NC_PUBKEY_SIZE); + + result = secp256k1_ec_pubkey_parse(ctx->secpCtx, pubKey, compressed, sizeof(compressed)); + + //zero everything + ZERO_FILL(compressed, sizeof(compressed)); + + return result; +} + +static inline int _convertFromXonly(const NCContext* ctx, const secp256k1_xonly_pubkey* xonly, NCPublicKey* compressedPubKey) +{ + DEBUG_ASSERT2(ctx != NULL, "Expected valid context") + DEBUG_ASSERT2(xonly != NULL, "Expected valid X-only secp256k1 public key structure.") + DEBUG_ASSERT2(compressedPubKey != NULL, "Expected a valid public 32byte pubkey structure") + + return secp256k1_xonly_pubkey_serialize(ctx->secpCtx, compressedPubKey->key, xonly); +} + +/* +* IMPL NOTES: +* This callback function will be invoked by the ecdh function to hash the shared point. +* +* For nostr, this operation is defined in the new NIP-44 spec here: +* https://github.com/nostr-protocol/nips/blob/master/44.md#encryption +* +* The x coordinate of the shared point is copied directly into the output buffer. No hashing is +* performed here. The y coordinate is not used, and for this implementation, there is no data +* pointer. +*/ +static int _edhHashFuncInternal( + unsigned char* output, + const uint8_t* x32, + const uint8_t* y32, + void* data +) +{ + ((void)y32); //unused for nostr + ((void)data); + + DEBUG_ASSERT2(output != NULL, "Expected valid output buffer") + DEBUG_ASSERT2(x32 != NULL, "Expected a valid public 32byte x-coodinate buffer") + + //Copy the x coordinate of the shared point into the output buffer + MEMMOV(output, x32, 32); + + return 32; //Return the number of bytes written to the output buffer +} + +static NCResult _computeSharedSecret( + const NCContext* ctx, + const NCSecretKey* sk, + const NCPublicKey* otherPk, + struct shared_secret* sharedPoint +) +{ + int result; + secp256k1_pubkey pubKey; + + DEBUG_ASSERT(ctx != NULL) + DEBUG_ASSERT(sk != NULL) + DEBUG_ASSERT(otherPk != NULL) + DEBUG_ASSERT(sharedPoint != NULL) + + //Recover pubkey from compressed public key data + if (_convertToPubKey(ctx, otherPk, &pubKey) != 1) + { + return E_INVALID_ARG; + } + + /* + * Compute the shared point using the ecdh function. + * + * The above callback is invoked to "compute" the hash (it + * copies the x coord) and it does not use the data pointer + * so it is set to NULL. + */ + result = secp256k1_ecdh( + ctx->secpCtx, + (uint8_t*)sharedPoint, + &pubKey, + sk->key, + &_edhHashFuncInternal, + NULL + ); + + //Clean up sensitive data + ZERO_FILL(&pubKey, sizeof(secp256k1_pubkey)); + + return (NCResult)result; +} + +static inline const mbedtls_md_info_t* _getSha256MdInfo(void) +{ + const mbedtls_md_info_t* info; + //Get sha256 md info for hdkf operations + info = mbedtls_md_info_from_type(MBEDTLS_MD_SHA256); + DEBUG_ASSERT2(info != NULL, "Expected SHA256 md info struct to be valid") + return info; +} + + +static inline NCResult _computeConversationKey( + const NCContext* ctx, + const mbedtls_md_info_t* mdInfo, + const struct shared_secret* sharedSecret, + struct conversation_key* ck +) +{ + //Validate internal args + DEBUG_ASSERT2(ctx != NULL, "Expected valid context") + DEBUG_ASSERT2(sharedSecret != NULL, "Expected a valid shared-point") + DEBUG_ASSERT2(mdInfo != NULL, "Expected valid md context") + DEBUG_ASSERT2(ck != NULL, "Expected a valid conversation key") + + //Derive the encryption key (returns 0 on success so it can be cast to an NCResult) + return (NCResult)mbedtls_hkdf_extract( + mdInfo, + Nip44ConstantSalt, + sizeof(Nip44ConstantSalt), + (uint8_t*)sharedSecret, //Shared secret is the input key + NC_SHARED_SEC_SIZE, + (uint8_t*)ck //Output produces a conversation key + ); +} + + +/* +* Explode the hkdf into the chacha key, chacha nonce, and hmac key. +*/ +static inline void _expandKeysFromHkdf(const struct message_key* hkdf, struct nc_expand_keys* keys) +{ + uint8_t* hkdfBytes; + + DEBUG_ASSERT2(hkdf != NULL, "Expected valid hkdf") + + hkdfBytes = (uint8_t*)hkdf; + + //Copy segments of the hkdf into the keys struct + MEMMOV( + keys->chacha_key, + hkdfBytes, + CHACHA_KEY_SIZE + ); + + MEMMOV( + keys->chacha_nonce, + (hkdfBytes + CHACHA_KEY_SIZE), + CHACHA_NONCE_SIZE + ); + + MEMMOV( + keys->hamc_key, + (hkdfBytes + CHACHA_KEY_SIZE + CHACHA_NONCE_SIZE), + HMAC_KEY_SIZE + ); +} + +static int _chachaEncipher(const struct nc_expand_keys* keys, NCCryptoData* args) +{ + int result; + mbedtls_chacha20_context chachaCtx; + + DEBUG_ASSERT2(keys != NULL, "Expected valid keys") + DEBUG_ASSERT2(args != NULL, "Expected valid encryption args") + DEBUG_ASSERT2(sizeof(keys->chacha_nonce) == 12, "Chacha nonce must be 12 exactly bytes in length") + + //Init the chacha context + mbedtls_chacha20_init(&chachaCtx); + + //Set the key and nonce + result = mbedtls_chacha20_setkey(&chachaCtx, keys->chacha_key); + DEBUG_ASSERT2(result == 0, "Expected chacha setkey to return 0") + + result = mbedtls_chacha20_starts(&chachaCtx, keys->chacha_nonce, 0); + DEBUG_ASSERT2(result == 0, "Expected chacha starts to return 0") + + //Encrypt the plaintext + result = mbedtls_chacha20_update(&chachaCtx, args->dataSize, args->inputData, args->outputData); + DEBUG_ASSERT2(result == 0, "Expected chacha update to return 0") + + //Clean up the chacha context + mbedtls_chacha20_free(&chachaCtx); + + return result; +} + +static inline NCResult _getMessageKey( + const mbedtls_md_info_t* mdInfo, + const struct conversation_key* converstationKey, + const uint8_t* nonce, + size_t nonceSize, + struct message_key* messageKey +) +{ + DEBUG_ASSERT2(mdInfo != NULL, "Expected valid md context") + DEBUG_ASSERT2(nonce != NULL, "Expected valid nonce buffer") + DEBUG_ASSERT2(converstationKey != NULL, "Expected valid conversation key") + DEBUG_ASSERT2(messageKey != NULL, "Expected valid message key buffer") + + //Another HKDF to derive the message key with nonce + return (NCResult)mbedtls_hkdf_expand( + mdInfo, + (uint8_t*)converstationKey, //Conversation key is the input key + NC_CONV_KEY_SIZE, + nonce, + nonceSize, + (uint8_t*)messageKey, //Output produces a message key + NC_MESSAGE_KEY_SIZE + ); +} + +static inline NCResult _encryptEx( + const NCContext* ctx, + const mbedtls_md_info_t* mdINfo, + const struct conversation_key* ck, + NCCryptoData* args +) +{ + NCResult result; + struct message_key messageKey; + struct nc_expand_keys cipherKeys; + + DEBUG_ASSERT2(ctx != NULL, "Expected valid context") + DEBUG_ASSERT2(ck != NULL, "Expected valid conversation key") + DEBUG_ASSERT2(args != NULL, "Expected valid encryption args") + + //Failure, bail out + if ((result = _getMessageKey(mdINfo, ck, args->nonce, NC_ENCRYPTION_NONCE_SIZE, &messageKey)) != NC_SUCCESS) + { + goto Cleanup; + } + + //Expand the keys from the hkdf so we can use them in the cipher + _expandKeysFromHkdf(&messageKey, &cipherKeys); + + //CHACHA20 + result = _chachaEncipher(&cipherKeys, args); + +Cleanup: + //Clean up sensitive data + ZERO_FILL(&messageKey, sizeof(messageKey)); + + return result; +} + +static inline NCResult _decryptEx( + const NCContext* ctx, + const mbedtls_md_info_t* mdInfo, + const struct conversation_key* ck, + NCCryptoData* args +) +{ + NCResult result; + struct message_key messageKey; + struct nc_expand_keys cipherKeys; + + //Assume message key buffer is the same size as the expanded key struct + DEBUG_ASSERT2(sizeof(messageKey) == sizeof(cipherKeys), "Message key size and expanded key sizes do not match") + + DEBUG_ASSERT2(ctx != NULL, "Expected valid context") + DEBUG_ASSERT2(ck != NULL, "Expected valid conversation key") + DEBUG_ASSERT2(args != NULL, "Expected valid encryption args") + DEBUG_ASSERT2(mdInfo != NULL, "Expected valid md info struct") + + //Failure to get message keys, bail out + if ((result = _getMessageKey(mdInfo, ck, args->nonce, NC_ENCRYPTION_NONCE_SIZE, &messageKey)) != NC_SUCCESS) + { + goto Cleanup; + } + + //Expand the keys from the hkdf so we can use them in the cipher + _expandKeysFromHkdf(&messageKey, &cipherKeys); + + //CHACHA20 + result = _chachaEncipher(&cipherKeys, args); + +Cleanup: + //Clean up sensitive data + ZERO_FILL(&messageKey, sizeof(messageKey)); + + return result; +} + +/* +* Compute the sha256 digest of the data. This function should always return 0 +* on success. +*/ +static inline int _computeSha256Digest(const uint8_t* data, size_t length, uint8_t digest[32]) +{ + int result; + mbedtls_sha256_context sha256; + + DEBUG_ASSERT2(data != NULL, "Expected valid data buffer") + DEBUG_ASSERT2(digest != NULL, "Expected valid digest buffer") + + //Init the sha256 context + mbedtls_sha256_init(&sha256); + + //starting context should never fail + result = mbedtls_sha256_starts(&sha256, 0); + DEBUG_ASSERT2(result == 0, "Expected sha256 starts to return 0") + + //may fail if the data is invalid + if ((result = mbedtls_sha256_update(&sha256, data, length)) != 0) + { + goto Cleanup; + } + + //Finishing context should never fail + result = mbedtls_sha256_finish(&sha256, digest); + +Cleanup: + //Always free the context + mbedtls_sha256_free(&sha256); + + return result; +} + +/* +* EXTERNAL API FUNCTIONS +*/ +NC_EXPORT uint32_t NC_CC NCGetContextStructSize(void) +{ + return sizeof(NCContext); +} + +NC_EXPORT NCResult NC_CC NCInitContext( + NCContext* ctx, + const uint8_t entropy[32] +) +{ + CHECK_NULL_PTR(ctx) + CHECK_NULL_PTR(entropy) + + ctx->secpCtx = secp256k1_context_create(SECP256K1_CONTEXT_NONE); + + //Randomize once on init + return secp256k1_context_randomize(ctx->secpCtx, entropy) ? NC_SUCCESS : E_INVALID_ARG; +} + +NC_EXPORT NCResult NC_CC NCReInitContext( + NCContext* ctx, + const uint8_t entropy[32] +) +{ + CHECK_NULL_PTR(ctx) + CHECK_INVALID_ARG(ctx->secpCtx) + CHECK_INVALID_ARG(entropy) + + //Only randomize again + return secp256k1_context_randomize(ctx->secpCtx, entropy) ? NC_SUCCESS : E_INVALID_ARG; +} + +NC_EXPORT NCResult NC_CC NCDestroyContext(NCContext* ctx) +{ + CHECK_NULL_ARG(ctx, 0); + CHECK_INVALID_ARG(ctx->secpCtx); + + //Destroy secp256k1 context + secp256k1_context_destroy(ctx->secpCtx); + + //Wipe the context + ZERO_FILL(ctx, sizeof(NCContext)); + + return NC_SUCCESS; +} + +//KEY Functions +NC_EXPORT NCResult NC_CC NCGetPublicKey( + const NCContext* ctx, + const NCSecretKey* sk, + NCPublicKey* pk +) +{ + int result; + secp256k1_keypair keyPair; + secp256k1_xonly_pubkey xonly; + + CHECK_NULL_ARG(ctx, 0) + CHECK_NULL_ARG(sk, 1) + CHECK_NULL_ARG(pk, 2) + CHECK_INVALID_ARG(ctx->secpCtx) + + if (secp256k1_keypair_create(ctx->secpCtx, &keyPair, sk->key) != 1) + { + return E_INVALID_ARG; + } + + //Generate the x-only public key, docs say this should always return 1 + result = secp256k1_keypair_xonly_pub(ctx->secpCtx, &xonly, NULL, &keyPair); + DEBUG_ASSERT2(result == 1, "Expected x-only kepair to ALWAYS return 1") + + //Convert to compressed pubkey + result = _convertFromXonly(ctx, &xonly, pk); + DEBUG_ASSERT2(result == 1, "Expected x-only pubkey serialize to return 1") + + //Clean out keypair + ZERO_FILL(&keyPair, sizeof(secp256k1_keypair)); + ZERO_FILL(&xonly, sizeof(secp256k1_xonly_pubkey)); + + return NC_SUCCESS; +} + +NC_EXPORT NCResult NC_CC NCValidateSecretKey( + const NCContext* ctx, + const NCSecretKey* sk +) +{ + CHECK_NULL_PTR(ctx) + CHECK_NULL_PTR(sk) + CHECK_INVALID_ARG(ctx->secpCtx) + + //Validate the secret key + return secp256k1_ec_seckey_verify(ctx->secpCtx, sk->key) ? NC_SUCCESS : E_INVALID_ARG; +} + +//Ecdsa Functions + +NC_EXPORT NCResult NC_CC NCSignDigest( + const NCContext* ctx, + const NCSecretKey* sk, + const uint8_t random32[32], + const uint8_t digest32[32], + uint8_t sig64[64] +) +{ + int result; + secp256k1_keypair keyPair; + secp256k1_xonly_pubkey xonly; + + //Validate arguments + CHECK_NULL_ARG(ctx, 0) + CHECK_NULL_ARG(sk, 1) + CHECK_NULL_ARG(random32, 2) + CHECK_NULL_ARG(digest32, 3) + CHECK_NULL_ARG(sig64, 4) + CHECK_INVALID_ARG(ctx->secpCtx) + + //Generate the keypair + if (secp256k1_keypair_create(ctx->secpCtx, &keyPair, sk->key) != 1) + { + return E_INVALID_ARG; + } + + //Sign the digest + result = secp256k1_schnorrsig_sign32(ctx->secpCtx, sig64, digest32, &keyPair, random32); + DEBUG_ASSERT2(result == 1, "Expected schnorr signature to return 1"); + + //x-only public key from keypair so the signature can be verified + result = secp256k1_keypair_xonly_pub(ctx->secpCtx, &xonly, NULL, &keyPair); + DEBUG_ASSERT2(result == 1, "Expected x-only public key to ALWAYS return 1"); + + //Verify the signature is valid + result = secp256k1_schnorrsig_verify(ctx->secpCtx, sig64, digest32, 32, &xonly); + + //cleanup any sensitive data + ZERO_FILL(&keyPair, sizeof(secp256k1_keypair)); + ZERO_FILL(&xonly, sizeof(secp256k1_xonly_pubkey)); + + return result == 1 ? NC_SUCCESS : E_INVALID_ARG; +} + +NC_EXPORT NCResult NC_CC NCSignData( + const NCContext* ctx, + const NCSecretKey* sk, + const uint8_t random32[32], + const uint8_t* data, + size_t dataSize, + uint8_t sig64[64] +) +{ + uint8_t digest[32]; + + CHECK_NULL_ARG(data, 2) + //CHECK_ARG_RANGE(dataSize, 1, UINT32_MAX, 3) + + //Compute sha256 of the data before signing + if(_computeSha256Digest(data, dataSize, digest) != 0) + { + return E_INVALID_ARG; + } + + //Sign the freshly computed digest + return NCSignDigest(ctx, sk, random32, digest, sig64); +} + +NC_EXPORT NCResult NC_CC NCVerifyDigest( + const NCContext* ctx, + const NCPublicKey* pk, + const uint8_t digest32[32], + const uint8_t sig64[64] +) +{ + int result; + secp256k1_xonly_pubkey xonly; + + DEBUG_ASSERT(&xonly != NULL) + + CHECK_NULL_ARG(ctx, 0) + CHECK_NULL_ARG(sig64, 1) + CHECK_NULL_ARG(digest32, 2) + CHECK_NULL_ARG(pk, 3) + CHECK_INVALID_ARG(ctx->secpCtx) + + //recover the x-only key from a compressed public key + if(_convertToXonly(ctx, pk, &xonly) != 1) + { + return E_INVALID_ARG; + } + + //Verify the signature + result = secp256k1_schnorrsig_verify(ctx->secpCtx, sig64, digest32, 32, &xonly); + + //cleanup any sensitive data + ZERO_FILL(&xonly, sizeof(secp256k1_xonly_pubkey)); + + return result == 1 ? NC_SUCCESS : E_INVALID_ARG; +} + +NC_EXPORT NCResult NC_CC NCVerifyData( + const NCContext* ctx, + const NCPublicKey* pk, + const uint8_t* data, + const size_t dataSize, + uint8_t sig64[64] +) +{ + uint8_t digest[32]; + + CHECK_NULL_ARG(data, 2) + //CHECK_ARG_RANGE(dataSize, 1, UINT32_MAX, 3) + + //Compute sha256 of the data before verifying + if (_computeSha256Digest(data, dataSize, digest) != 0) + { + return E_INVALID_ARG; + } + + //Verify the freshly computed digest + return NCVerifyDigest(ctx, pk, digest, sig64); +} + +//ECDH Functions +NC_EXPORT NCResult NC_CC NCGetSharedSecret( + const NCContext* ctx, + const NCSecretKey* sk, + const NCPublicKey* otherPk, + uint8_t sharedPoint[NC_SHARED_SEC_SIZE] +) +{ + CHECK_NULL_ARG(ctx, 0) + CHECK_NULL_ARG(sk, 1) + CHECK_NULL_ARG(otherPk, 2) + CHECK_NULL_ARG(sharedPoint, 3) + CHECK_INVALID_ARG(ctx->secpCtx) + + return _computeSharedSecret( + ctx, + sk, + otherPk, + (struct shared_secret*)sharedPoint + ); +} + +NC_EXPORT NCResult NC_CC NCGetConversationKeyEx( + const NCContext* ctx, + const uint8_t sharedPoint[NC_SHARED_SEC_SIZE], + uint8_t conversationKey[NC_CONV_KEY_SIZE] +) +{ + CHECK_NULL_ARG(ctx, 0) + CHECK_NULL_ARG(sharedPoint, 1) + CHECK_NULL_ARG(conversationKey, 2) + CHECK_INVALID_ARG(ctx->secpCtx) + + //Cast the shared point to the shared secret type + return _computeConversationKey( + ctx, + _getSha256MdInfo(), + (struct shared_secret*)sharedPoint, + (struct conversation_key*)conversationKey + ); +} + +NC_EXPORT NCResult NC_CC NCGetConversationKey( + const NCContext* ctx, + const NCSecretKey* sk, + const NCPublicKey* pk, + uint8_t conversationKey[NC_CONV_KEY_SIZE] +) +{ + NCResult result; + struct shared_secret sharedSecret; + const mbedtls_md_info_t* mdInfo; + + CHECK_NULL_ARG(ctx, 0) + CHECK_NULL_ARG(sk, 1) + CHECK_NULL_ARG(pk, 2) + CHECK_NULL_ARG(conversationKey, 3) + CHECK_INVALID_ARG(ctx->secpCtx) + + mdInfo = _getSha256MdInfo(); + + //Compute the shared point + if ((result = _computeSharedSecret(ctx, sk, pk, &sharedSecret)) != NC_SUCCESS) + { + goto Cleanup; + } + + result = _computeConversationKey( + ctx, + mdInfo, + &sharedSecret, + (struct conversation_key*)conversationKey + ); + +Cleanup: + //Clean up sensitive data + ZERO_FILL(&sharedSecret, sizeof(sharedSecret)); + + return result; +} + +NC_EXPORT NCResult NC_CC NCEncryptEx( + const NCContext* ctx, + const uint8_t conversationKey[NC_CONV_KEY_SIZE], + NCCryptoData* args +) +{ + CHECK_NULL_ARG(ctx, 0) + CHECK_NULL_ARG(conversationKey, 1) + CHECK_NULL_ARG(args, 2) + + //Validate the context + CHECK_INVALID_ARG(ctx->secpCtx) + + //Validte ciphertext/plaintext + CHECK_INVALID_ARG(args->inputData) + CHECK_INVALID_ARG(args->outputData) + CHECK_ARG_RANGE(args->dataSize, NIP44_MIN_ENC_MESSAGE_SIZE, NIP44_MAX_ENC_MESSAGE_SIZE, 3) + + return _encryptEx( + ctx, + _getSha256MdInfo(), + (struct conversation_key*)conversationKey, + args + ); +} + +NC_EXPORT NCResult NC_CC NCEncrypt( + const NCContext* ctx, + const NCSecretKey* sk, + const NCPublicKey* pk, + NCCryptoData* args +) +{ + NCResult result; + const mbedtls_md_info_t* mdInfo; + struct shared_secret sharedSecret; + struct conversation_key ck; + + CHECK_NULL_ARG(ctx, 0) + CHECK_NULL_ARG(sk, 1) + CHECK_NULL_ARG(pk, 2) + CHECK_NULL_ARG(args, 3) + + //Validate the context + CHECK_INVALID_ARG(ctx->secpCtx) + + //Validate input/output data + CHECK_INVALID_ARG(args->inputData) + CHECK_INVALID_ARG(args->outputData) + CHECK_ARG_RANGE(args->dataSize, NIP44_MIN_ENC_MESSAGE_SIZE, NIP44_MAX_ENC_MESSAGE_SIZE, 3) + + mdInfo = _getSha256MdInfo(); + + //Compute the shared point + if ((result = _computeSharedSecret(ctx, sk, pk, &sharedSecret)) != NC_SUCCESS) + { + goto Cleanup; + } + + //Compute the conversation key from secret and pubkic keys + if ((result = _computeConversationKey(ctx, mdInfo, &sharedSecret, &ck)) != NC_SUCCESS) + { + goto Cleanup; + } + + result = _encryptEx(ctx, mdInfo, &ck, args); + +Cleanup: + //Clean up sensitive data + ZERO_FILL(&sharedSecret, sizeof(sharedSecret)); + ZERO_FILL(&ck, sizeof(ck)); + + return result; +} + + +NC_EXPORT NCResult NC_CC NCDecryptEx( + const NCContext* ctx, + const uint8_t conversationKey[NC_CONV_KEY_SIZE], + NCCryptoData* args +) +{ + CHECK_NULL_ARG(ctx, 0) + CHECK_NULL_ARG(conversationKey, 1) + CHECK_NULL_ARG(args, 2) + + //Validate the context + CHECK_INVALID_ARG(ctx->secpCtx) + + //Validte ciphertext/plaintext + CHECK_INVALID_ARG(args->inputData) + CHECK_INVALID_ARG(args->outputData) + CHECK_ARG_RANGE(args->dataSize, NIP44_MIN_DEC_MESSAGE_SIZE, NIP44_MAX_DEC_MESSAGE_SIZE, 3) + + return _decryptEx( + ctx, + _getSha256MdInfo(), + (struct conversation_key*)conversationKey, + args + ); +} + + +NC_EXPORT NCResult NC_CC NCDecrypt( + const NCContext* ctx, + const NCSecretKey* sk, + const NCPublicKey* pk, + NCCryptoData* args +) +{ + NCResult result; + struct shared_secret sharedSecret; + struct conversation_key conversationKey; + const mbedtls_md_info_t* mdInfo; + + CHECK_NULL_ARG(ctx, 0) + CHECK_NULL_ARG(sk, 1) + CHECK_NULL_ARG(pk, 2) + CHECK_NULL_ARG(args, 3) + + //Validate the context + CHECK_INVALID_ARG(ctx->secpCtx) + + //Validte ciphertext/plaintext + CHECK_INVALID_ARG(args->inputData) + CHECK_INVALID_ARG(args->outputData) + CHECK_ARG_RANGE(args->dataSize, NIP44_MIN_DEC_MESSAGE_SIZE, NIP44_MAX_DEC_MESSAGE_SIZE, 3) + + mdInfo = _getSha256MdInfo(); + + if ((result = _computeSharedSecret(ctx, sk, pk, &sharedSecret)) != NC_SUCCESS) + { + goto Cleanup; + } + + if ((result = _computeConversationKey(ctx, mdInfo, &sharedSecret, &conversationKey)) != NC_SUCCESS) + { + goto Cleanup; + } + + result = _decryptEx(ctx, mdInfo, &conversationKey, args); + +Cleanup: + //Clean up sensitive data + ZERO_FILL(&sharedSecret, sizeof(sharedSecret)); + ZERO_FILL(&conversationKey, sizeof(conversationKey)); + + return result; +} + -- cgit