diff --git a/book/source/04-certificates.md b/book/source/04-certificates.md
index 6b4f746..806e492 100644
--- a/book/source/04-certificates.md
+++ b/book/source/04-certificates.md
@@ -67,7 +67,7 @@ Each OpenPGP component key possesses an *OpenPGP fingerprint*. This fingerprint
 
 ```{figure} diag/Fingerprint.png
 
-Every OpenPGP component key is identifiable by a unique fingerprint.
+Every OpenPGP component key is identifiable by a  fingerprint. Although it's technically possible for different keys to share a fingerprint, cryptographic mechanisms make it exceedingly difficult, if not practically impossible with current technology, to find keys that share a fingerprint.
 ```
 
 The fingerprint of our example OpenPGP component key is `C0A5 8384 A438 E5A1 4F73 7124 26A4 D45D  BAEE F4A3 9E6B 30B0 9D55 13F9 78AC CA94`[^keyid].