diff --git a/checksums.R b/checksums.R
new file mode 100644
index 0000000..c424c88
--- /dev/null
+++ b/checksums.R
@@ -0,0 +1,94 @@
+# From Stata
+
+# if $redownload == 1 {
+#    copy "https://datahub.io/core/country-codes/r/country-codes.csv" "data/raw/country-codes.csv", replace
+#    // create checksum of file
+#    // Aug 2023 version: 2295658388
+#    global countrycksum 2295658388
+#    checksum "data/raw/country-codes.csv", save
+#    assert $countrycksum == r(checksum)
+#    // This will fail if the files are not identical
+#    // Provide a verbose message if we get past this point
+#    disp in green "Country codes file downloaded successfully"
+# } 
+
+library(dplyr)
+library(openssl)
+library(tools)
+
+# Function to calculate SHA256 hash of a file
+calculate_sha256 <- function(filepath) {
+  tryCatch({
+    hash <- sha256(file(filepath))
+    # Convert the raw vector to a single hexadecimal string
+    as.character(hash, sep = "")
+  }, error = function(e) {
+    NA_character_
+  })
+}
+
+# Function to verify checksum
+verify_checksum <- function(filepath, expected_hash) {
+  calculated_hash <- calculate_sha256(filepath)
+  if (is.na(calculated_hash)) {
+    return(FALSE)
+  }
+  return(calculated_hash == expected_hash)
+}
+
+# Flags
+
+reprocess <- TRUE
+generate  <- TRUE
+
+# filepaths - generalized - this could be in an externally sourced file treated as confidential
+
+data.path <- "data/"
+data.path.external <- file.path(data.path,"external")
+data.path.registry <- file.path(data.path,"registry")
+data.path.metadata <- file.path(data.path,"metadata")
+
+
+if ( generate ) {
+    metadata <- read.csv(file.path(data.path.metadata,"consistency.csv"))
+    # Add SHA256 hash column
+    metadata <- metadata %>%
+        rowwise() %>%
+        mutate(sha256sum = calculate_sha256(file.path(get(path), filename)),
+        asofdate=date()) %>%
+        select(filename,path,sha256sum,asofdate)
+    # Write the updated metadata back to a CSV file
+    write.csv(metadata, file.path(data.path.metadata,"consistency.csv"), 
+              row.names = FALSE)
+}
+
+# check the checksums before proceeding
+
+# Verify all checksums in the metadata
+metadata <- read.csv(file.path(data.path.metadata,"consistency.csv"))
+metadata <- metadata %>%
+  rowwise() %>%
+  mutate(checksum_verified =
+           verify_checksum(file.path(get(paste0("data.path.",path)), filename), sha256sum)
+           )
+
+# Display results
+message("Verification results for files")
+print(metadata %>% select(filename, sha256sum, checksum_verified))
+
+# Count of verified and failed checksums
+summary <- metadata %>%
+  ungroup() %>%
+  summarise(
+    total_files = n(),
+    verified = sum(checksum_verified),
+    failed = sum(!checksum_verified)
+  )
+print(summary)
+
+if ( reprocess ) {
+    # Do stuff here 
+}
+
+
+
diff --git a/data/metadata/consistency.csv b/data/metadata/consistency.csv
index 1e59e37..0a2a8d2 100644
--- a/data/metadata/consistency.csv
+++ b/data/metadata/consistency.csv
@@ -1,8 +1,8 @@
-filename,path,checksum,date
-anes_timeseries_2020_stata_20220210_hill_roberts_subset.csv,external,,2024-09-11
-China2021Data.csv,external,,2024-09-11
-LucidPlotText.csv,external,,2024-09-11
-LucidWideFile.csv,external,,2024-09-11
-Pre2020Surveys_Pooled.csv,external,,2024-09-11
-trials.Rds,registry,,2024-09-11
-consistency.csv,metadata,,2024-09-11
+"filename","path","sha256sum","asofdate"
+"anes_timeseries_2020_stata_20220210_hill_roberts_subset.csv","external","75d050817b922b02b444b58c279f5d770f01376321d894c80b76364063248b63","Fri Sep 13 07:53:19 2024"
+"China2021Data.csv","external","2ce75c757229ddb631cadccc9c4063537de313d3a754fed13f93054656261bba","Fri Sep 13 07:53:19 2024"
+"LucidPlotText.csv","external","992daee8392ebeee510290a7b5895d53028c358b892a9d7c10a6391b5d979194","Fri Sep 13 07:53:19 2024"
+"LucidWideFile.csv","external","767eb7b05fc1910603780680476cf32fee845728b4c7346e9f0ada6ed0c84f04","Fri Sep 13 07:53:19 2024"
+"Pre2020Surveys_Pooled.csv","external","17b6cc33b8bdc3938aab5b59de0dc4fa2b724d1ad997060385466d0899dae82e","Fri Sep 13 07:53:19 2024"
+"trials.Rds","registry","07e0a48dc2bb5896fd89540915f431eb6e1b36b374c848c1edfbabee8d5e6ad7","Fri Sep 13 07:53:19 2024"
+"consistency.csv","metadata","2732f4a0fa6a580fc601266ed34e76d6b276a256a09e95232022b7b53f4a9025","Fri Sep 13 07:53:19 2024"