add note that detached sig has checksum, not original data

1 files changed, 3 insertions, 1 deletions

diff --git a/sq-guide.md b/sq-guide.md
index eb652e8..3a641b6 100644
--- a/sq-guide.md
+++ b/sq-guide.md
@@ -623,7 +623,9 @@ sq sign --detached --signer-key key.pgp -o foo-sig.pgp foo.md
 
 Note the `--detached` option. The signature, but none of the original
 data, is written to `foo-sig.pgp`. The detached signature is small,
-and its size does not depend on the size of the signed data.
+and its size does not depend on the size of the signed data. That's
+because the detached signature contains the _cryptographic checksum_
+of the original data.
 
 ## Verifying a signature