Symmetric Key Generation Specifications

Note:

Currently in the beta phase.

This section describes the algorithms currently supported by the system and their corresponding specifications.

Developers can generate corresponding keys by using string parameters to carry key specifications. The supported string parameters for each algorithm will be introduced in the specific algorithm specifications.

AES

AES (Advanced Encryption Standard), the most common symmetric encryption algorithm.

Basic features:

• Block cipher algorithm with a block length of 128 bits.
• Key lengths of 128 bits, 192 bits, or 256 bits.
• Compared to 3DES, it offers higher security and faster processing speed.

Currently supports generating AES keys using string parameters. The specific "string parameter" is formed by concatenating the "symmetric key algorithm" and "key length," used to specify the key specification when creating a symmetric key generator.

Symmetric Key Algorithm	Key Length (bit)	String Parameter	API Version
AES	128	AES128	12+
AES	192	AES192	12+
AES	256	AES256	12+

3DES

3DES (Triple Data Encryption Algorithm), also known as 3DESede or TripleDES.

Basic features:

• Uses three 64-bit keys to perform triple encryption on data, equivalent to applying the DES (Data Encryption Standard) encryption algorithm three times to each data block.
• Compared to DES, 3DES has longer key lengths and higher security but slower processing speed than DES.

Currently supports generating 3DES keys using string parameters. The specific "string parameter" is formed by concatenating the "symmetric key algorithm" and "key length," used to specify the key specification when creating a symmetric key generator.

Symmetric Key Algorithm	Key Length (bit)	String Parameter	API Version
3DES	192	3DES192	12+

SM4

SM4, the SM4 block cipher algorithm.

Basic features:

• Block cipher algorithm with a block length of 128 bits.
• Key length of 128 bits. The key length can be increased through key expansion.
• Both the encryption algorithm and key expansion algorithm use a 32-round nonlinear iterative structure. The algorithm structures for data decryption and data encryption are the same, except that the order of round keys is reversed—the decryption round keys are the inverse of the encryption round keys.

Currently supports generating SM4 keys using string parameters. The specific "string parameter" is formed by concatenating the "symmetric key algorithm" and "key length" with the connector "_," used to specify the key specification when creating a symmetric key generator.

Symmetric Key Algorithm	Key Length (bit)	String Parameter	API Version
SM4	128	SM4_128	12+

HMAC

HMAC (Hash-based Message Authentication Code), a hash-based message authentication code algorithm that requires a symmetric key as input.

Basic features of HMAC:

• The symmetric key used can be of any length:
  • If the key length exceeds the HMAC block length, the result of a one-way hash of the key is used as the new key.
  • If the key length is less than the HMAC block length, it is padded with zeros at the end to form the new key, ensuring the final key length matches the HMAC block length.
• The recommended key length is the output length of the digest algorithm.

Currently supports generating symmetric keys for HMAC using string parameters:

• When the HMAC key length matches the output length of the digest algorithm, the specific "string parameter" is formed by concatenating the "message authentication code algorithm" and "digest algorithm" with the connector "|," used to specify the key specification when creating a symmetric key generator.
• When the HMAC key length falls outside the output length range of the above digest algorithms, the symmetric key generator can be created using the string parameter "HMAC," and the key can be generated based on the binary data of the HMAC key.

Message Authentication Code Algorithm	Digest Algorithm	Key Length (bit)	String Parameter	API Version
HMAC	SHA1	160	HMAC|SHA1	12+
HMAC	SHA224	224	HMAC|SHA224	12+
HMAC	SHA256	256	HMAC|SHA256	12+
HMAC	SHA384	384	HMAC|SHA384	12+
HMAC	SHA512	512	HMAC|SHA512	12+
HMAC	SM3	256	HMAC|SM3	12+
HMAC	-	[1, 32768]	HMAC	12+