Library: file encryption/decryption support #163
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an4tur0r
commented
Nov 11, 2022
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| const char* enc_filepath = strcat((char*)path, ENCRYPTION_EXT); | ||
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| if(file_stream_open(stream_from, path, FSAM_READ, FSOM_OPEN_EXISTING) && |
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Unit test hangs here, I suspect something with Storage* instance.
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Fasjeit
reviewed
Jan 14, 2023
| // create new random initialization vector | ||
| uint8_t iv[ENCRYPTION_IV_SIZE]; | ||
| srand(DWT->CYCCNT); | ||
| furi_hal_random_fill_buf(iv, ENCRYPTION_IV_SIZE); |
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IV is generated here using srand PRNG + CYCCNT (i.e. cycle counter) as seed,
- Only 32 bits of "entropy" for CYCCNT link
- Predicted (CYCCNT is just incrementing counter), making predicted IV attacks possible (like complete plaintext recovery for low entropy plaintexts) as the resulted encryption is no longer CPA secure
- srand is not a secure PRG (even with better seed as it has only 31 bit inner state)
Original flipper firmware already implemented much better random generation using sts32 hardware random generator. See furi_hal_random.c rand() function which can be used instead of srand.
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Any updates to this? |
baretta881
approved these changes
Jun 13, 2023
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What's new
This PR adds functions to encrypt and decrypt file content using AES algorithm.
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