# Can I get successful signature verification with just altering message and signature?

Assuming I can modify a message and also modify the verification signature, and I also have the public-key but not the private-key. Can I create a message that can be verified with a signature that I can create and get a successful verification operation ?

I'm using the RSACryptoServiceProvider.VerifyHash method, we calculate rgbHash = sha1(message)

RSACryptoServiceProvider.VerifyHash(
byte[] rgbHash,
string str, //we used SHA1
byte[] rgbSignature
)


Is there any possiblity to make a successful verification with just modifying message and signature, and without modifying public-key ?