A key is required to generate a digital signature. You must prepare the MD5 key or the RSA/RSA2 private and public key pair to generate and verify a digital signature. After generating the keys, you need to exchange keys with Alipay.

For more information, see:

• Digital signature
• Key pair generation and validation

RSA Key Generation with OpenSSL

OpenSSL installation

Linux (Ubuntu)

sudo apt-get install openssl

Windows

The developer can download the Windows version of OpenSSL from the official OpenSSL site.

RSA key pair generation

Linux

$ openssl

OpenSSL> genrsa -out rsa_private_key.pem 1024 ##generating private key

OpenSSL> pkcs8 -topk8 -inform PEM -in rsa_private_key.pem -outform PEM -nocrypt ##transform private key into PKCS8 format

OpenSSL> rsa -in rsa_private_key.pem -pubout -out rsa_public_key.pem ##Generate public key

OpenSSL> exit

Windows operates in cmd window

C:\Users\Hammer>cd C:\OpenSSL-Win32\bin ##enter OpenSSL directory

C:\OpenSSL-Win32\bin>openssl.exe ##enter OpenSSL

OpenSSL> genrsa -out rsa_private_key.pem 1024  ##generating private key

OpenSSL> pkcs8 -topk8 -inform PEM -in rsa_private_key.pem -outform PEM -nocrypt ##transform private key into PKCS8 format

OpenSSL> rsa -in rsa_private_key.pem -pubout -out rsa_public_key.pem ##Generate public key

OpenSSL> exit

Note:

Java developers need to remove the header, footer, <CR>, and space from the pkcs8 private key output in the console. As for .NET and PHP developers, the pkcs8 operation is not needed.

After completing the steps above, the user can see two files under the current folder (C:\OpenSSL-Win32\bin for Windows): rsaprivatekey.pem (private key) and rsapublickey.pem (public key). The merchant should keep the private key and exchange the public key with Alipay for signature verification. The following are examples of how to use the key pair.

Standard private key file (PHP, .NET)

-----BEGIN RSA PRIVATE KEY-----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

-----END RSA PRIVATE KEY-----

Standard private key file in PKCS8 format (Java)

-----BEGIN PRIVATE KEY-----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

-----END PRIVATE KEY-----

Public key file

-----BEGIN PUBLIC KEY-----MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDQWiDVZ7XYxa4CQsZoB3n7bfxLDkeGKjyQPt2FUtm4TWX9OYrd523iw6UUqnQ+Evfw88JgRnhyXadp+vnPKP7unormYQAfsM/CxzrfMoVdtwSiGtIJB4pfyRXjA+KL8nIa2hdQy5nLfgPVGZN4WidfUY/QpkddCVXnZ4bAUaQjXQIDAQAB

-----END PUBLIC KEY-----

Upload the public key

Contact Alipay technical support at overseas_support@service.alibaba.com to upload the public key. Sign with the matching private key in the key pair.