RSA SHA256 signing in iOS and verification on Java

Question

1. I generated an RSA key pair with SecKeyGeneratePair. The key size in bits is 2048.

   NSDictionary *privateAttributes = @{(NSString *)kSecAttrIsPermanent:          
   
   
           

Answer 1

Digital signature API for iOS and Java is different but the result is the same.

iOS SecKeyRawSign with kSecPaddingPKCS1SHA256 uses a SHA256 digest, but in Java Signature.sign requires the raw data and it makes digest+pkcs1. Use

instance.update(rawString.toString().getBytes("UTF-8"));