143 lines
4.1 KiB
C++
143 lines
4.1 KiB
C++
#include "encryption_helper.h"
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#include <QTextStream>
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#include <QVariantMap>
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#include <QDebug>
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#include "openssl/evp.h"
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int gcm_encrypt(const char *plaintext, int plaintext_len,
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const char *key, const char *iv, int iv_len,
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char *ciphertext)
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{
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return gcm_encrypt((uchar*)plaintext, plaintext_len,
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(uchar*)key, (uchar*)iv, iv_len,
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(uchar*)ciphertext);
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}
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int gcm_decrypt(const char *ciphertext, int ciphertext_len,
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const char *key,
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const char *iv, int iv_len,
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char *plaintext)
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{
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return gcm_decrypt((uchar*)ciphertext, ciphertext_len,
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(uchar*)key, (uchar*)iv, iv_len,
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(uchar*)plaintext);
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}
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void handleErrors() {
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qDebug() << "handleErrors";
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}
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int generate_key_and_iv(unsigned char *iv, unsigned char *key) {
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// unsigned char key[32];
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// unsigned char iv[16];
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// EVP_BytesToKey(EVP_aes_256_gcm(), EVP_md5(),
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// NULL,
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// key_file_buf, key_size, 1, // const unsigned char *data, int datal, int count,
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// key, iv);
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return 0;
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}
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int gcm_encrypt(const unsigned char *plaintext, int plaintext_len,
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const unsigned char *key,
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const unsigned char *iv, int iv_len,
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unsigned char *ciphertext)
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{
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EVP_CIPHER_CTX *ctx;
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int len;
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int ciphertext_len;
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/* Create and initialise the context */
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if(!(ctx = EVP_CIPHER_CTX_new()))
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handleErrors();
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/* Initialise the encryption operation. */
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if(1 != EVP_EncryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL))
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handleErrors();
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/*
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* Set IV length if default 12 bytes (96 bits) is not appropriate
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*/
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if(1 != EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, iv_len, NULL))
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handleErrors();
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/* Initialise key and IV */
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if(1 != EVP_EncryptInit_ex(ctx, NULL, NULL, key, iv))
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handleErrors();
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/*
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* Provide the message to be encrypted, and obtain the encrypted output.
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* EVP_EncryptUpdate can be called multiple times if necessary
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*/
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if(1 != EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len))
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handleErrors();
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ciphertext_len = len;
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/*
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* Finalise the encryption. Normally ciphertext bytes may be written at
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* this stage, but this does not occur in GCM mode
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*/
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if(1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, &len))
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handleErrors();
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ciphertext_len += len;
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/* Clean up */
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EVP_CIPHER_CTX_free(ctx);
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return ciphertext_len;
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}
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int gcm_decrypt(const unsigned char *ciphertext, int ciphertext_len,
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const unsigned char *key,
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const unsigned char *iv, int iv_len,
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unsigned char *plaintext)
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{
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EVP_CIPHER_CTX *ctx;
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int len;
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int plaintext_len;
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int ret;
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/* Create and initialise the context */
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if(!(ctx = EVP_CIPHER_CTX_new()))
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handleErrors();
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/* Initialise the decryption operation. */
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if(!EVP_DecryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL))
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handleErrors();
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/* Set IV length. Not necessary if this is 12 bytes (96 bits) */
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if(!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_IVLEN, iv_len, NULL))
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handleErrors();
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/* Initialise key and IV */
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if(!EVP_DecryptInit_ex(ctx, NULL, NULL, key, iv))
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handleErrors();
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/*
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* Provide the message to be decrypted, and obtain the plaintext output.
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* EVP_DecryptUpdate can be called multiple times if necessary
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*/
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if(!EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, ciphertext_len))
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handleErrors();
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plaintext_len = len;
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/*
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* Finalise the decryption. A positive return value indicates success,
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* anything else is a failure - the plaintext is not trustworthy.
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*/
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ret = EVP_DecryptFinal_ex(ctx, plaintext + len, &len);
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/* Clean up */
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EVP_CIPHER_CTX_free(ctx);
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if(ret > 0) {
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/* Success */
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plaintext_len += len;
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return plaintext_len;
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} else {
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/* Verify failed */
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return -1;
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}
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}
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