First, that's not a "digital signature", it's a MAC. It's the secret-suffix SHA1 MAC, to be precise.
Second, the secret-suffix SHA1 MAC isn't secure. Its insecurity is the reason we have HMAC.
This seems to me to be the kind of thing you'd want to get right if the whole value proposition of your solution was "verifying URLs with cryptography".
Comments
First, that's not a "digital signature", it's a MAC. It's the secret-suffix SHA1 MAC, to be precise.
Second, the secret-suffix SHA1 MAC isn't secure. Its insecurity is the reason we have HMAC.
This seems to me to be the kind of thing you'd want to get right if the whole value proposition of your solution was "verifying URLs with cryptography".