Encryption process

sensitive_data field data:

{
	"merchant_order_id": "20231204204337871860ET82009",
	"merchant_user_key": "2312312addsadsaasdsadsadadcdsacadsas",
	"country_code": "GBR",
	"currency_code": "GBP",
	"tuition": 130,
	"merchant_service_fee": 130,
	"order_tuition": 0,
	"name_ch": "\u6d4b\u8bd5\u6d4b\u8bd5\u6d4b\u8bd5",
	"student_id_number": "130633199302285495",
	"student_address": "\u7684\u6492\u6240\u591a\u591a\u6492\u5927\u6240\u5927",
	"apartment_name": "\u5b9e\u65bd\u5927\u5931\u8d25222\u8fc7\u8d1f\u8377222\u4e3a",
	"student_email": "162455379cds7@qq.com",
	"student_mobile": "19935437csd743",
	"wechat_number": "199354377csd43",
	"city_name_en": "Belfast",
	"city_name_ch": "\u4f26\u6566",
	"school_name": "University of London",
	"fee_type_list": [{
		"fee_type": 7,
		"fee_type_desc": "\u623f\u79df"
	}],
	"notify_url": "xxxxxxx",
	"back_jump_url": ""
}

1.Sensitive_ If data has no value, it is an empty string and does not need to be encrypted. If there is a value, it needs to be encrypted. The following are the encryption rules

1.1.Convert sensitive_data to json format data, use aes-128-cbc for symmetric encryption, generate aes key KeyStr (random value generation 16-bit byte), offset IVStr (using KeyStr) as two parameters, encrypt the data using these two parameters to generate ciphertext Cipher, convert Cipher to base64 encoding, and fill CipherBase64 into sensitive_data.
1.2Use the public key (the public key of ET) to perform RSA (PKCS V1.5 OEAP) encryption with SHA256 on keystr to obtain Cipher_keystr
1.3Cipher_keystr is converted to base64 encoding to obtain base64_keystr, and finally the base64_keystr is filled into aeskey
Filled data:
{
"serial_number": "20231204204337871860ET82009",
"merchant_number": "ET82009",
"sub_merchant_number": "ET82009S001",
"server_type": "add_special_rent_order",
"callback_process": 1,
"version": "2.0.0",
"data": "{}",
"return_info": "",
"extend_info": "",
"sensitive_data": "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",
"aeskey": "iWRwvJXElKlehwz5Bvc2+GryrYISJdJhSMG1N697K9/3nikzRxGC85I6i14Kh6hCvrwlPPHV1o1Qy6s4ugzgConYef78meMRbWX3j/JgDB1ZZS5XxkyB2Vt+kFCqNV85dslL2j+rknEC+OcqW9fGjYs7GG19fQ0wynQ0gl7guXU="}

2.Signature

Concatenate String

Sort all fields (except sign) alphabetically (a-z) by field name

Join key-value pairs using & separator

Example：

aeskey=iWRwvJXElKle...&callback_process=1&data={}&extend_info=&merchant_number=ET82009&return_info=&sensitive_data=gWyCgwZU...&serial_number=20231204204337871860ET82009&server_type=add_special_rent_order&sub_merchant_number=ET82009S001&version=2.0.0

Calculate Signature

Convert the string to bytes (UTF-8 encoding)

Calculate SHA1 digest to get a 40-character hexadecimal string

Calculate the SHA1 digest of the string to be signed

Sign the digest obtained in the previous step using the merchant's private key

Signature algorithm: SHA256withRSA (PKCS#1 v1.5 padding)

Note: No need to calculate SHA256 hash again

Convert the signature result to Base64 encoding

Python Signature Example：

Interface encryption and signing steps

Encryption process#

1.Sensitive_ If data has no value, it is an empty string and does not need to be encrypted. If there is a value, it needs to be encrypted. The following are the encryption rules#

2.Signature#

Encryption process

1.Sensitive_ If data has no value, it is an empty string and does not need to be encrypted. If there is a value, it needs to be encrypted. The following are the encryption rules

2.Signature