Update prerequisites-41d8559.md Fix typos

docs/prerequisites-41d8559.md

@@ -171,7 +171,7 @@ Set `sp.signature_private_key` and `sp.signature_private_key_password` if you se
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-Add `exchange_key` to sign tokens, or remove line. Provide a random key with an even character length \(minimum length: 32\) of alphanumeric characters \(A-Z, a-z, 0-9\). The system generates a randome key f the key is not provided.
+Add `exchange_key` to sign tokens, or remove line. Provide a random key with an even character length \(minimum length: 32\) of alphanumeric characters \(A-Z, a-z, 0-9\). The system generates a random key if the key is not specified.
 
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