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diff --git a/unit04_public_key/lab/gpg/hello.txt b/unit04_public_key/lab/gpg/hello.txt
index e965047..1cbf8c7 100644
--- a/unit04_public_key/lab/gpg/hello.txt
+++ b/unit04_public_key/lab/gpg/hello.txt
@@ -1 +1,5 @@
-Hello
+Hello.
+
+Thanks for the message.
+
+-- Bill
diff --git a/unit04_public_key/lab/gpg/hello.txt.asc b/unit04_public_key/lab/gpg/hello.txt.asc
index 1acded8..f83ce60 100644
--- a/unit04_public_key/lab/gpg/hello.txt.asc
+++ b/unit04_public_key/lab/gpg/hello.txt.asc
@@ -1,14 +1,15 @@
 -----BEGIN PGP MESSAGE-----
 
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+=tlFI
 -----END PGP MESSAGE-----
diff --git a/unit04_public_key/lab/gpg/msg01.txt b/unit04_public_key/lab/gpg/msg01.txt
new file mode 100644
index 0000000..ee6d530
--- /dev/null
+++ b/unit04_public_key/lab/gpg/msg01.txt
@@ -0,0 +1,20 @@
+-----BEGIN PGP MESSAGE-----
+
+
+
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+=HKvb
+-----END PGP MESSAGE-----
diff --git a/unit04_public_key/lab/gpg/pub01.key b/unit04_public_key/lab/gpg/pub01.key
new file mode 100644
index 0000000..ec9142d
--- /dev/null
+++ b/unit04_public_key/lab/gpg/pub01.key
@@ -0,0 +1,43 @@
+-----BEGIN PGP PUBLIC KEY BLOCK-----
+
+
+
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+=OP+1
+-----END PGP PUBLIC KEY BLOCK-----
diff --git a/unit04_public_key/lab/gpg/student.asc b/unit04_public_key/lab/gpg/student.asc
new file mode 100644
index 0000000..e976e5e
--- /dev/null
+++ b/unit04_public_key/lab/gpg/student.asc
@@ -0,0 +1,23 @@
+-----BEGIN PGP MESSAGE-----
+
+
+
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+-----END PGP MESSAGE-----
diff --git a/unit05_key_exchange/.DS_Store b/unit05_key_exchange/.DS_Store
index 9666d24..003e392 100644
Binary files a/unit05_key_exchange/.DS_Store and b/unit05_key_exchange/.DS_Store differ
diff --git a/unit05_key_exchange/lab/new_lab05.docx b/unit05_key_exchange/lab/new_lab05.docx
index 16d2ca5..4ccc51e 100644
Binary files a/unit05_key_exchange/lab/new_lab05.docx and b/unit05_key_exchange/lab/new_lab05.docx differ
diff --git a/unit05_key_exchange/lecture/unit05_key_exchange.pptx b/unit05_key_exchange/lecture/unit05_key_exchange.pptx
index d885256..f6eaf35 100644
Binary files a/unit05_key_exchange/lecture/unit05_key_exchange.pptx and b/unit05_key_exchange/lecture/unit05_key_exchange.pptx differ
diff --git a/z_sim_hash/ssdeep b/z_sim_hash/ssdeep
new file mode 100644
index 0000000..e689bdb
--- /dev/null
+++ b/z_sim_hash/ssdeep
@@ -0,0 +1,4 @@
+import ssdeep
+hash1 = ssdeep.hash('Also called fuzzy hashes, Ctph can match inputs that have homologies.')
+'3:AXGBicFlgVNhBGcL6wCrFQEv:AXGHsNhxLsr2C'
+>>> hash2 = ssdeep.hash('Also called fuzzy hashes, CTPH can match inputs that have homologies.')