QByteArray QAES::decrypt(QByteArray cyphertext, QByteArray key, QByteArray iv){ ERR_clear_error(); // 检查密钥合法性(只能是16、24、32字节) Q_ASSERT(key.size() == 32 ); Q_ASSERT(iv.size() == 16);

QByteArray plaintext; QScopedPointer ctx(EVP_CIPHER_CTX_new());

if (!EVP_DecryptInit_ex(ctx.data(), EVP_aes_256_cbc(), NULL, (unsigned char *)key.data(), (unsigned char *)iv.data())) { plaintext.clear(); return plaintext; } if (!EVP_CIPHER_CTX_set_padding(ctx.data(), EVP_PADDING_PKCS7)) { plaintext.clear(); return plaintext; } int outlen = 0; plaintext.resize(cyphertext.size()); if (!EVP_DecryptUpdate(ctx.data(), (unsigned char *)plaintext.data(), &outlen, (unsigned char *)cyphertext.data(), cyphertext.size())) { plaintext.clear(); return plaintext; } int tmplen = 0; if (!EVP_DecryptFinal_ex(ctx.data(), (unsigned char *)plaintext.data() + outlen, &tmplen)) { plaintext.clear(); return plaintext; } return plaintext.left(outlen + tmplen);}

QByteArray QAES::encrypt(QByteArray plaintext, QByteArray key, QByteArray iv){ ERR_clear_error(); // 检查密钥合法性(只能是16、24、32字节) Q_ASSERT(key.size() == 32 ); Q_ASSERT(iv.size() == 16);

QByteArray cyphertext; QScopedPointer ctx(EVP_CIPHER_CTX_new());

if (!EVP_EncryptInit_ex(ctx.data(), EVP_aes_256_cbc(), NULL, (unsigned char*)key.data(), (unsigned char*)iv.data())) { cyphertext.clear(); return cyphertext; } if (!EVP_CIPHER_CTX_set_padding(ctx.data(), EVP_PADDING_PKCS7)) { cyphertext.clear(); return cyphertext; } int outlen = 0; cyphertext.resize(plaintext.size() + 16); if (!EVP_EncryptUpdate(ctx.data(), (unsigned char *)cyphertext.data(), &outlen, (const unsigned char *)plaintext.data(), plaintext.size())) { cyphertext.clear(); return cyphertext; } int tmplen = 0; if (!EVP_EncryptFinal_ex(ctx.data(), (unsigned char *)cyphertext.data() + outlen, &tmplen)) { cyphertext.clear(); return cyphertext; }

return cyphertext.left(outlen + tmplen);}

QString QAES::GetLastError(){ unsigned long lastError = ERR_peek_last_error(); if (lastError == 0) { return ""; } char errorString[256]; ERR_error_string_n(lastError, errorString, sizeof(errorString)); return errorString;}