Encrypted Hilink Uimage Firmware Header Apr 2026

Example decrypted header (hexdump):

Check for HiLink markers:

| Offset | Size | Field | Example Value | |--------|------|---------------|-------------------| | 0x00 | 4 | ih_magic | 0x27051956 | | 0x04 | 4 | ih_hcrc | Checksum | | 0x08 | 4 | ih_time | Timestamp | | 0x0C | 4 | ih_size | Data size | | 0x10 | 4 | ih_load | Load address | | 0x14 | 4 | ih_ep | Entry point | | 0x18 | 4 | ih_dcrc | Data checksum | | 0x1C | 1 | ih_os | OS type | | 0x1D | 1 | ih_arch | Architecture | | 0x1E | 1 | ih_type | Image type | | 0x1F | 1 | ih_comp | Compression | | 0x20 | 16 | ih_name | Image name |

If you’ve ever run binwalk on a HiLink firmware update (e.g., from an E3372, B310, or AR series router) and seen only high entropy data with no recognizable UImage magic ( 0x27051956 ), you’ve likely encountered this encrypted header. encrypted hilink uimage firmware header

cipher = AES.new(key, AES.MODE_CBC, iv) dec_header = cipher.decrypt(enc_header)

This article explains what it is, how it works, and practical methods to decrypt and analyze it. A normal, unencrypted UImage header (64 bytes) looks like this:

strings u-boot.bin | grep -i "aes" Look for key arrays in rodata section. hexdump -C firmware

hexdump -C firmware.bin | head -n 20 Look for strings like "HUAWEI" , "HiLink" , or "UPDATE" at offset > 0x1000 (they often appear after the encrypted header). Method A – Static key (older devices) Search U-Boot binary (extracted via JTAG or from a decrypted image):

If the magic appears, you have the correct key. The rest of the firmware may be encrypted in blocks. Many HiLink images encrypt only the header + first block. The remaining data may be plain or compressed. After decryption, run:

magic = struct.unpack(">I", dec_header[0:4])[0] if magic == 0x27051956: print("Decryption successful") with open("dec_header.bin", "wb") as out: out.write(dec_header) The encrypted HiLink UImage header is a modest but effective speed bump against casual analysis. For a determined reverse engineer, it adds a few hours of work—identifying the key source, decrypting, and repacking. However, modern per-device keys and additional signature checks make widespread third-party firmware creation impractical. Many HiLink images encrypt only the header + first block

binwalk -E firmware.bin If the first 1 MB shows high entropy (>0.98) with no known signatures, suspect encryption.

with open("firmware.bin", "rb") as f: enc_header = f.read(4096)