diff --git a/README.md b/README.md
index 44f2ad3..3b0dc2e 100644
--- a/README.md
+++ b/README.md
@@ -38,7 +38,7 @@ The ["I am starting from scratch" quick-start guide](<2.2. I am starting from sc
         2. [Reusable root modules](<docs/3.1.2. Reusable root modules.md>)
         3. [Jinja templating for Terraform](<docs/3.1.3. Jinja templating for Terraform.md>)
         4. [Jinja templating for variables](<docs/3.1.4. Jinja templating for variables.md>)
-        5. [Remote lookup functions](<docs/3.1.5. Remote lookup functions.md>)
+        5. [Custom Jinja functions](<docs/3.1.5. Custom Jinja functions.md>)
         6. [Inline secret encryption](<docs/3.1.6. Inline secret encryption.md>)
         7. [Automatic variable initialization](<docs/3.1.7. Automatic variable initialization.md>)
     2. Features you can build with Stacks
diff --git a/docs/3.1.5. Remote lookup functions.md b/docs/3.1.5. Custom Jinja functions.md
similarity index 63%
rename from docs/3.1.5. Remote lookup functions.md
rename to docs/3.1.5. Custom Jinja functions.md
index 4c28811..464220d 100644
--- a/docs/3.1.5. Remote lookup functions.md	
+++ b/docs/3.1.5. Custom Jinja functions.md	
@@ -1,9 +1,9 @@
-# Remote lookup functions
+# Custom Jinja functions
 
 With Jinja you get to inject your own custom functions to be used in templating, so of course we do.
 
-## The `variable` lookup function
-With the `variable` lookup function you can fetch any variable value off any other layer in your repository.
+## The `variable` function
+With the `variable` function you can fetch any variable value off any other layer in your repository.
 ### Example 1: fetching a `vpc_id` variable from the same layer in a different stack
 ```hcl
 # stacks/ec2/stack.tfvars.jinja:
@@ -20,18 +20,26 @@ vpc_id = "{{ variable("vpc_id", stack="vpc", environment="production") }}"
 vpc_id = "{{ variable("vpc_id", stack="vpc", environment="development", subenvironment="us-east-1", instance="foo") }}"  # stack/environment/subenvironment/instance all default to the caller's
 ```
 
-## The `output` lookup function
-With the `output` lookup function you can fetch any output value off the state of any other layer in your repository.
+## The `output` function
+With the `output` function you can fetch any output value off the state of any other layer in your repository.
 ### Example 1: fetching a `vpc_id` output from the same layer in a different stack
 ```hcl
 # stacks/ec2/stack.tfvars.jinja:
 vpc_id = "{{ output("vpc_id", stack="vpc") }}"
 ```
 
-## The `resource` lookup function
-With the `resource` lookup function you can fetch any resource attributes off the state of any other layer in your repository.
+## The `resource` function
+With the `resource` function you can fetch any resource attributes off the state of any other layer in your repository.
 ### Example 1: fetching a `aws_vpc.main` resource from the same layer in a different stack
 ```hcl
 # stacks/ec2/stack.tfvars.jinja:
 vpc_id = "{{ resource("aws_vpc.main", stack="vpc")["id"] }}"
 ```
+
+## The `md5`, `sha1`, `sha256` and `sha512` functions
+With these functions you can generate the MD5, SHA-1, SHA-256 and SHA-512 checksums respectively of a given string.
+### Example
+```hcl
+# stacks/ec2/stacks.tfvars.jinja
+foo_md5 = "{{ md5("foo") }}"
+```