Edited ch04.asciidoc with Atlas code editor

ch04.asciidoc

@@ -115,7 +115,7 @@ Elliptic curve multiplication is a type of function that cryptographers call a "
 [[elliptic_curve]]
 ==== Elliptic Curve Cryptography Explained
 
-((("keys and addresses", "overview of", "elliptic curve cryptography")))((("elliptic curve cryptography")))Elliptic curve cryptography is a type of asymmetric or public-key cryptography based on the discrete logarithm problem as expressed by addition and multiplication on the points of an elliptic curve. 
+((("keys and addresses", "overview of", "elliptic curve cryptography")))((("elliptic curve cryptography", id="eliptic04")))Elliptic curve cryptography is a type of asymmetric or public-key cryptography based on the discrete logarithm problem as expressed by addition and multiplication on the points of an elliptic curve. 
 
 <<ecc-curve>> is an example of an elliptic curve, similar to that used by bitcoin.
 
@@ -189,7 +189,7 @@ If P~1~ is the "point at infinity," then the sum P~1~ + P~2~ = P~2~. Similary, i
 
 It turns out that pass:[+] is associative, which means that (A pass:[+] B) pass:[+] C = A pass:[+] (B pass:[+] C). That means we can write A pass:[+] B pass:[+] C without parentheses without any ambiguity. 
 
-Now that we have defined addition, we can define multiplication in the standard way that extends addition. For a point P on the elliptic curve, if k is a whole number, then kP = P + P + P + ... + P (k times). Note that k is sometimes confusingly called an "exponent" in this case. 
+Now that we have defined addition, we can define multiplication in the standard way that extends addition. For a point P on the elliptic curve, if k is a whole number, then kP = P + P + P + ... + P (k times). Note that k is sometimes confusingly called an "exponent" in this case.((("", startref="eliptic04"))) 
 
 [[public_key_derivation]]
 ==== Generating a Public Key