Key Import Overview and Algorithm Specifications
You can import an externally generated key (for example, a key generated after key agreement or generated by a server) into HUKS for management. Once a key is imported into HUKS, the plaintext can be accessed only in a secure environment in its lifecycle. This ensures that no one can obtain the plaintext of the key.
A key can be imported in plaintext or in encrypted (wrapped) mode.
Plaintext Import
Importing a key in plaintext may expose the plaintext to a non-secure environment. This import mode applies to lightweight devices or security-insensitive services.
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Plaintext import is recommended to import the public key of an asymmetric key pair.
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It is not recommended to import symmetric keys or asymmetric key pairs.
Encrypted Import
In this mode, the key to be imported is encrypted (wrapped) and then imported to HUKS through an end-to-end encrypted transmission channel established between the service and HUKS. This mode applies to security-sensitive services due to higher security than plaintext import. However, it involves more complex key material and operations.
- Encrypted import is recommended to import symmetric keys or asymmetric key pairs.
The following figure illustrates the development sequence of encrypted import.
To import an encrypted key, you need to use the HUKS APIs to generate a key pair (used to encrypt the key to be imported), export the public key, import the encrypted key, and delete the key pair.
The public key material exported is encapsulated in X.509 format. The encrypted key material to be imported must be encapsulated in LengthData< /sub>-Data format.
Key Material Format for Encrypted Import
Content | Length |
---|---|
Service public key Caller_Pk length (LCaller_Pk) | 4 bytes |
Service public key Caller_Pk | LCaller_Pk bytes |
Shared_Key AAD2 length (LAAD2) | 4 bytes |
Shared_Key AAD2 | LAAD2 bytes |
Shared_Key Nonce2 length (LNonce2) | 4 bytes |
Shared_Key Nonce2 | LNonce2 bytes |
Shared_Key AEAD2 length (LAEAD2) | 4 bytes |
Shared_Key AEAD2 | LAEAD2 bytes |
Caller_Kek_enc length (LCaller_Kek_enc) | 4 bytes |
Caller_Kek ciphertext Caller_Kek_enc | LCaller_Kek_enc bytes |
Caller_Kek AAD3 length (LAAD3) | 4 bytes |
Caller_Kek AAD3 | LAAD3 bytes |
Caller_Kek Nonce3 length (LNonce3) | 4 bytes |
Caller_Kek Nonce3 | LNonce3 bytes |
Caller_Kek AEAD3 length (LAEAD3) | 4 bytes |
Caller_Kek AEAD3 | LAEAD3 bytes |
To_Import_Key_size length (LTo_Import_Key_size) | 4 bytes |
Key plaintext material length To_Import_Key_size | LTo_Import_Key_size bytes |
To_Import_Key_enc length (LTo_Import_Key_enc) | 4 bytes |
To_Import_Key ciphertext To_Import_Key_enc | LTo_Import_Key_enc bytes |
Supported Algorithms
The following table lists the supported key import specifications.
The key management service specifications include mandatory specifications and optional specifications. Mandatory specifications are algorithm specifications that must be supported. Optional specifications can be used based on actual situation. Before using the optional specifications, refer to the documents provided by the vendor to ensure that the specifications are supported.
You are advised to use mandatory specifications in your development for compatibility purposes.
Algorithm | Supported Key Length (Bit) | API Level | Mandatory |
---|---|---|---|
AES | 128, 192, 256 | 8+ | Yes |
RSA | 512, 768, 1024 | 8+ | No |
RSA | 2048, 3072, 4096 | 8+ | Yes |
HMAC | An integer multiple of 8, ranging from 8 to 1024 (inclusive) | 8+ | Yes |
ECC | 224 | 8+ | No |
ECC | 256, 384, 521 | 8+ | Yes |
ED25519 | 256 | 8+ | Yes |
X25519 | 256 | 8+ | Yes |
DSA | An integer multiple of 8, ranging from 512 to 1024 (inclusive) | 8+ | No |
DH | 2048 | 8+ | Yes |
DH | 3072, 4096 | 8+ | No |
SM2 | 256 | 9+ | Yes |
SM4 | 128 | 9+ | Yes |