验证由 Windows Crypto API 创建的 Java 签名

Question

I have signature created by Crypto API

if(!CryptCreateHash(hProv, CALG_MD5, 0, 0, &Hash))
    return;         
if(!CryptHashData(Hash, Buff,count, 0))
    return;     
if(CryptSignHash(Hash,AT_SIGNATURE,NULL,0,Buff,&count))
...

I want to verify the signature in Java.

C++ generates a key length of 148 bytes, I need a java 162. I generate it using http://www.jensign.com/JavaScience/MSKeytoJKey/ . To check out 162 generated 148 coincide.

Then I try to verify the signature

Signature dsa   = Signature.getInstance("MD5WithRSA");
dsa.initVerify(rsapublickey);
dsa.update(Text);
Sign = dsa.verify(TextSign);

You guessed it, the value of Sign is false. What have I missed and is this really going anywhere?

Answer 1

The native cryptography API uses little-endian byte order while the .NET Framework and JAVA uses big-endian byte order. If you are verifying a signature generated by using Crypto API, you must swap the order of signature bytes before calling function to verify the signature in Java.