diff --git a/README.md b/README.md
index 39c79735..f5dc360c 100644
--- a/README.md
+++ b/README.md
@@ -96,7 +96,7 @@ If you invoke an AppImage built with a recent version of AppImageKit with one of
 - `--appimage-mount` mounts the embedded filesystem image and prints the mount point, then waits until it is killed. This is useful if you would like to inspect the contents of an AppImage without executing the contained payload application
 - `--appimage-version` prints the version of AppImageKit, then exits. This is useful if you would like to file issues
 - `--appimage-updateinformation` prints the update information embedded into the AppImage, then exits. This is useful for debugging binary delta updates
-- `--appimage-signature` prints the digital signature embedded into the AppImage, then exits. This is useful for debugging binary delta updates. If you would like to validate the embedded signature, you should use the `validate` command line tool that is part of AppImageKit
+- `--appimage-signature` prints the digital signature embedded into the AppImage, then exits. This is useful for debugging binary delta updates. If you would like to validate the embedded signature, you should use the `validate` command line tool that is part of AppImageUpdate and can be downloaded [here](https://github.com/AppImageCommunity/AppImageUpdate/releases).
 
 ### Special directories
 
diff --git a/src/validate.c b/src/validate.c
deleted file mode 100644
index 7e8ce30c..00000000
--- a/src/validate.c
+++ /dev/null
@@ -1,204 +0,0 @@
-#include <glib.h>
-#include <glib/gprintf.h>
-#include <stdio.h>
-#include <string.h>
-#include <errno.h>
-#include <openssl/sha.h>
-#include <stdlib.h>
-#include <sys/stat.h>
-#include <linux/limits.h>
-#include <unistd.h>
-#include <libgen.h>
-#include <fcntl.h>
-#include <sys/mman.h>
-
-#include "appimage/appimage.h"
-#include "appimage/appimage_shared.h"
-#include "light_elf.h"
-
-typedef unsigned char byte;      
-
-char segment_name[] = ".sha256_sig";
-char segment_key_name[] = ".sig_key";
-
-int sha256_file(char *path, char outputBuffer[65], int skip_offset, int skip_length)
-{
-    FILE *file = fopen(path, "rb");
-    if(!file) return(1);
-    byte hash[SHA256_DIGEST_LENGTH];
-    SHA256_CTX sha256;
-    SHA256_Init(&sha256);
-    const int bufSize = 1024*1024;
-    byte *buffer = malloc(bufSize);
-    int bytesRead = 0;
-    if(!buffer) {
-        fclose(file);
-        return ENOMEM;
-    }
-
-    int totalBytesRead = 0;
-    if(skip_offset <= bufSize){
-        bytesRead = fread(buffer, 1, skip_offset, file);
-        totalBytesRead += bytesRead;
-        // printf("totalBytesRead: %i\n", totalBytesRead);
-        // printf("bytesRead: %i\n", bytesRead);
-        SHA256_Update(&sha256, buffer, bytesRead);
-    } else {
-        int stillToRead = skip_offset-bytesRead;
-        // printf("Initial stillToRead: %i\n", stillToRead);
-        int readThisTime;
-
-        if(stillToRead>bufSize){
-            readThisTime = bufSize;
-        } else {
-            readThisTime = stillToRead;
-        }
-        while((bytesRead = fread(buffer, 1, readThisTime, file)))
-        {
-            totalBytesRead += bytesRead;
-            // printf("totalBytesRead: %i\n", totalBytesRead);
-            // printf("readThisTime: %i\n", readThisTime);
-            // printf("bytesRead: %i\n", bytesRead);
-            SHA256_Update(&sha256, buffer, bytesRead);
-            stillToRead = skip_offset-totalBytesRead;
-            // printf("stillToRead: %i\n", stillToRead);
-
-            if(stillToRead>bufSize){
-                readThisTime = bufSize;
-            } else {
-                readThisTime = stillToRead;
-            }
-        }
-    }
-
-    fseek(file, skip_offset+skip_length, SEEK_SET);
-    
-    /* Instead of the skipped area, calculate the sha256 of the same amount if 0x00s */
-    int i = 0;
-    for(i = 0; i < skip_length; i++) {
-        SHA256_Update(&sha256, "\0", 1);
-        totalBytesRead += 1;
-    }
-        
-    while((bytesRead = fread(buffer, 1, bufSize, file)))
-    {
-        totalBytesRead += bytesRead;
-        // printf("totalBytesRead: %i\n", totalBytesRead);
-        // printf("bytesRead: %i\n", bytesRead);
-        SHA256_Update(&sha256, buffer, bytesRead);
-    }
-    SHA256_Final(hash, &sha256);
-
-    // fprintf(stderr, "totalBytesRead: %i\n", totalBytesRead);
-    
-    for(i = 0; i < SHA256_DIGEST_LENGTH; i++)
-    {
-        sprintf(outputBuffer + (i * 2), "%02x", hash[i]);
-    }
-    outputBuffer[64] = 0;
-
-    fclose(file);
-    
-    return 0;
-}
-
-int main(int argc,char **argv)	{
-    if(argc < 2){
-        fprintf(stderr, "Usage: %s Signed.AppImage\n", argv[0]);
-        exit(1);
-    }
-
-    char *filename = argv[1]; 
-
-    unsigned long skip_offset_sig = 0;
-    unsigned long skip_length_sig = 0;
-
-    unsigned long skip_offset_key = 0;
-    unsigned long skip_length_key = 0;
-  
-    if (!appimage_get_elf_section_offset_and_length(filename, ".sha256_sig", &skip_offset_sig, &skip_length_sig)) {
-        fprintf(stderr, "Failed to read .sha256_sig section");
-        exit(1);
-    }
-    if (!appimage_get_elf_section_offset_and_length(filename, ".sig_key", &skip_offset_key, &skip_length_key)) {
-        skip_length_key = 0;
-        skip_offset_key = 0;
-    }
-
-    if(skip_length_sig > 0) {
-        fprintf(stderr, "Skipping ELF section %s with offset %lu, length %lu\n", segment_name, skip_offset_sig, skip_length_sig);
-    } else {
-        fprintf(stderr, "ELF section %s not found, is the file signed?\n", segment_name);
-        exit(1);
-    }
-    if(skip_length_key > 0) {
-        fprintf(stderr, "Skipping ELF section %s with offset %lu, length %lu\n", segment_key_name, skip_offset_key, skip_length_key);
-    } else {
-        fprintf(stderr, "ELF section %s not found, assuming older AppImage Standard\n", segment_key_name);
-    }
-    if(skip_offset_sig + skip_length_sig != skip_offset_key && skip_length_key != 0) {
-        fprintf(stderr, "validate only works when .sha256_sig and .sig_key are contiguous in the ELF header\n");
-        exit(0);
-    }
-    int skip_offset = skip_offset_sig;
-    int skip_length = skip_length_sig + skip_length_key;
-    
-    char *digestfile;
-    digestfile = g_strconcat("/tmp/", basename(g_strconcat(filename, ".digest", NULL)), NULL);
-    char *signaturefile;
-    signaturefile = g_strconcat("/tmp/", basename(g_strconcat(filename, ".sig", NULL)), NULL);
-
-    uint8_t *data = malloc(skip_length_sig);
-    unsigned long k;
-    FILE* fd = fopen(filename, "r");
-    fseek(fd, skip_offset_sig, SEEK_SET);
-    fread(data, skip_length_sig, sizeof(uint8_t), fd);
-    fclose(fd);
-    FILE *fpdst2 = fopen(signaturefile, "w");
-    if (fpdst2 == NULL) {
-        fprintf(stderr, "Not able to open the signature file for writing, aborting");
-        exit(1);
-    }
-    for (k = 0; k < skip_length_sig; k++) {
-        fprintf(fpdst2, "%c", data[k]);
-    }   
-    fclose(fpdst2);
-    free(data);
-    
-    struct stat st;
-    stat(filename, &st);
-    int size = st.st_size;
-    if(size < skip_offset+skip_length){
-        fprintf(stderr, "offset+length cannot be less than the file size\n");
-        exit(1);
-    }
-
-    static char buffer[65];
-    sha256_file(filename, buffer, skip_offset, skip_length);
-    printf("%s\n", buffer);
-    
-
-    FILE *f = fopen(digestfile, "w");
-    if (f == NULL){
-        printf("Error opening digestfile\n");
-        exit(1);
-    }
-    fprintf(f, "%s", buffer);
-    fclose(f);
-    if (! g_file_test(digestfile, G_FILE_TEST_IS_REGULAR)) {
-        printf("Error writing digestfile\n");
-        exit(1);        
-    }
-    
-    char command[1024];
-    gchar *gpg2_path = g_find_program_in_path ("gpg2");
-    sprintf (command, "%s --verify %s %s", gpg2_path, signaturefile, digestfile);
-    fprintf (stderr, "%s\n", command);
-    FILE *fp = popen(command, "r");
-    if (fp == NULL)
-        fprintf(stderr, "gpg2 command did not succeed");
-    int exitcode = WEXITSTATUS(pclose(fp));
-    unlink(digestfile);
-    unlink(signaturefile);
-    return exitcode;
-}