diff --git a/tests/common.sh b/tests/common.sh
new file mode 100755
index 0000000000..82fdb85081
--- /dev/null
+++ b/tests/common.sh
@@ -0,0 +1,39 @@
+#!/bin/bash
+
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Determine script directory.
+if [[ $0 == '/'* ]]; 
+then
+  SCRIPT_DIR="`dirname $0`"
+elif [[ $0 == './'* ]];
+then
+  SCRIPT_DIR="`pwd`"
+else
+  SCRIPT_DIR="`pwd`"/"`dirname $0`"
+fi
+
+UTIL_DIR=`dirname ${SCRIPT_DIR}`/utils
+TEST_DIR=${SCRIPT_DIR}
+TESTKEY_DIR=${SCRIPT_DIR}/testkeys
+TESTCASE_DIR=${SCRIPT_DIR}/testcases
+
+# Color output encodings.
+COL_RED='\E[31;1m'
+COL_GREEN='\E[32;1m'
+COL_YELLOW='\E[33;1m'
+COL_BLUE='\E[34;1m'
+COL_STOP='\E[0;m'
+
+hash_algos=( sha1 sha256 sha512 )
+key_lengths=( 1024 2048 4096 8192 ) 
+
+function check_test_keys {
+  if [ ! -d ${TESTKEY_DIR} ]
+  then
+    echo "You must run gen_test_keys.sh to generate test keys first."
+    exit 1
+  fi
+}
diff --git a/tests/gen_fuzz_test_cases.sh b/tests/gen_fuzz_test_cases.sh
index fc97f4b1ae..7f75a31151 100755
--- a/tests/gen_fuzz_test_cases.sh
+++ b/tests/gen_fuzz_test_cases.sh
@@ -6,14 +6,13 @@
 
 # Generate test cases for use for the RSA verify benchmark.
 
-TESTCASE_DIR=fuzz_testcases
-TESTKEY_DIR=testkeys
-UTIL_DIR=../utils/
-TEST_FILE=test_file 
-TEST_FILE_SIZE=1000000
+# Load common constants and variables.
+. "$(dirname "$0")/common.sh"
 
-hash_algos=( sha1 sha256 sha512 )
-key_lengths=( 1024 2048 4096 8192 ) 
+# Use a different directory for fuzzing test cases.
+TESTCASE_DIR=${SCRIPT_DIR}/fuzz_testcases
+TEST_FILE=${TESTCASE_DIR}/testfile
+TEST_FILE_SIZE=500000
 
 # Generate public key signatures and digest on an input file for 
 # various combinations of message digest algorithms and RSA key sizes.
@@ -47,22 +46,11 @@ function generate_fuzzing_images {
 }
 
 function pre_work {
-  # Generate a file with random bytes for signature tests.
+  # Generate a file to serve as random bytes for firmware/kernel contents.
   echo "Generating test file..."
-  dd if=/dev/urandom of=${TESTCASE_DIR}/${TEST_FILE} bs=${TEST_FILE_SIZE} \
-    count=1
+  dd if=/dev/urandom of=${TEST_FILE} bs=${TEST_FILE_SIZE} count=1
 }
-
-if [ ! -d ${TESTKEY_DIR} ]
-then
-  echo "You must run gen_test_keys.sh to generate test keys first."
-  exit 1
-fi
-
-if [ ! -d ${TESTCASE_DIR} ]
-then
-  mkdir ${TESTCASE_DIR}
-fi
-
+mkdir -p ${TESTCASE_DIR}
 pre_work
-generate_fuzzing_images ${TESTCASE_DIR}/$TEST_FILE
+check_test_keys
+generate_fuzzing_images ${TEST_FILE}
diff --git a/tests/gen_test_cases.sh b/tests/gen_test_cases.sh
index b15921d61e..bad7e334d4 100755
--- a/tests/gen_test_cases.sh
+++ b/tests/gen_test_cases.sh
@@ -6,49 +6,39 @@
 
 # Generate test cases for use for the RSA verify benchmark.
 
-KEY_DIR=testkeys
-TESTCASE_DIR=testcases
-UTIL_DIR=../utils/
-TEST_FILE=test_file 
+# Load common constants and variables.
+. "$(dirname "$0")/common.sh"
+
+TEST_FILE=${TESTCASE_DIR}/test_file
 TEST_FILE_SIZE=1000000
 
-hash_algos=( sha1 sha256 sha512 )
-key_lengths=( 1024 2048 4096 8192 ) 
-
-# Generate public key signatures and digest on an input file for 
-# various combinations of message digest algorithms and RSA key sizes.
+# Generate public key signatures on an input file for various combinations
+# of message digest algorithms and RSA key sizes.
 function generate_test_signatures {
+  echo "Generating test signatures..."
   algorithmcounter=0
   for keylen in ${key_lengths[@]}
   do
     for hashalgo in ${hash_algos[@]}
     do
-      openssl dgst -${hashalgo} -binary -out $1.${hashalgo}.digest $1
-      ${UTIL_DIR}/signature_digest $algorithmcounter $1 | openssl rsautl -sign \
-        -pkcs -inkey ${KEY_DIR}/key_rsa${keylen}.pem \
-        > $1.rsa${keylen}_${hashalgo}.sig
+      openssl dgst -${hashalgo} -binary ${TEST_FILE} > \
+        ${TEST_FILE}.${hashalgo}.digest
+      ${UTIL_DIR}/signature_digest_utility $algorithmcounter  \
+        ${TEST_FILE} | openssl rsautl \
+        -sign -pkcs -inkey ${TESTKEY_DIR}/key_rsa${keylen}.pem \
+        > ${TEST_FILE}.rsa${keylen}_${hashalgo}.sig
       let algorithmcounter=algorithmcounter+1
     done
   done
 }
 
-function pre_work {
-  # Generate a file with random bytes for signature tests.
+# Generate a file with random bytes for signature tests.
+function generate_test_file {
   echo "Generating test file..."
-  dd if=/dev/urandom of=${TESTCASE_DIR}/${TEST_FILE} bs=${TEST_FILE_SIZE} count=1
+  dd if=/dev/urandom of=${TEST_FILE} bs=${TEST_FILE_SIZE} count=1
 }
 
-if [ ! -d "$KEY_DIR" ]
-then
-  echo "You must run gen_test_cases.sh to generate test keys first."
-  exit 1
-fi
-
-if [ ! -d "$TESTCASE_DIR" ]
-then
-  mkdir  "$TESTCASE_DIR"
-fi
-
-pre_work
-echo "Generating test signatures..."
-generate_test_signatures ${TESTCASE_DIR}/$TEST_FILE
+mkdir -p ${TESTCASE_DIR}
+check_test_keys
+generate_test_file
+generate_test_signatures
diff --git a/tests/gen_test_keys.sh b/tests/gen_test_keys.sh
index 2a8fe83e68..bb39fb281f 100755
--- a/tests/gen_test_keys.sh
+++ b/tests/gen_test_keys.sh
@@ -3,30 +3,25 @@
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
-
+#
 # Generate test keys for use by the tests.
 
-KEY_DIR=testkeys
-key_lengths=( 1024 2048 4096 8192 ) 
-UTIL_DIR=../utils/
+# Load common constants and variables.
+. "$(dirname "$0")/common.sh"
 
 # Generate RSA test keys of various lengths. 
 function generate_keys {
   for i in ${key_lengths[@]}
   do
-    openssl genrsa -F4 -out ${KEY_DIR}/key_rsa$i.pem $i
+    openssl genrsa -F4 -out ${TESTKEY_DIR}/key_rsa$i.pem $i
     # Generate self-signed certificate from key.
-    openssl req -batch -new -x509 -key ${KEY_DIR}/key_rsa$i.pem \
-      -out ${KEY_DIR}/key_rsa$i.crt
+    openssl req -batch -new -x509 -key ${TESTKEY_DIR}/key_rsa$i.pem \
+      -out ${TESTKEY_DIR}/key_rsa$i.crt
     # Generate pre-processed key for use by RSA signature verification code.
-    ${UTIL_DIR}/dumpRSAPublicKey ${KEY_DIR}/key_rsa$i.crt \
-      > ${KEY_DIR}/key_rsa$i.keyb
+    ${UTIL_DIR}/dumpRSAPublicKey ${TESTKEY_DIR}/key_rsa$i.crt \
+      > ${TESTKEY_DIR}/key_rsa$i.keyb
   done
 }
 
-if [ ! -d "$KEY_DIR" ]
-then
-  mkdir  "$KEY_DIR"
-fi
-
+mkdir -p ${TESTKEY_DIR}
 generate_keys
diff --git a/tests/run_image_verification_tests.sh b/tests/run_image_verification_tests.sh
index 19feae2378..3eba26ee06 100755
--- a/tests/run_image_verification_tests.sh
+++ b/tests/run_image_verification_tests.sh
@@ -6,17 +6,10 @@
 
 # Run verified boot firmware and kernel verification tests. 
 
-return_code=0
-hash_algos=( sha1 sha256 sha512 )
-key_lengths=( 1024 2048 4096 8192 ) 
-TEST_FILE=test_file 
-TEST_FILE_SIZE=1000000
+# Load common constants and variables.
+. "$(dirname "$0")/common.sh"
 
-COL_RED='\E[31;1m'
-COL_GREEN='\E[32;1m'
-COL_YELLOW='\E[33;1m'
-COL_BLUE='\E[34;1m'
-COL_STOP='\E[0;m'
+return_code=0
 
 function test_firmware_verification {
   algorithmcounter=0
@@ -26,10 +19,10 @@ function test_firmware_verification {
     do
       echo -e "For Root key ${COL_YELLOW}RSA-$keylen/$hashalgo${COL_STOP}:"
       cd ${UTIL_DIR} && ${TEST_DIR}/firmware_image_tests $algorithmcounter \
-        ${TEST_DIR}/testkeys/key_rsa8192.pem \
-        ${TEST_DIR}/testkeys/key_rsa8192.keyb \
-        ${TEST_DIR}/testkeys/key_rsa${keylen}.pem \
-        ${TEST_DIR}/testkeys/key_rsa${keylen}.keyb
+        ${TESTKEY_DIR}/key_rsa8192.pem \
+        ${TESTKEY_DIR}/key_rsa8192.keyb \
+        ${TESTKEY_DIR}/key_rsa${keylen}.pem \
+        ${TESTKEY_DIR}/key_rsa${keylen}.keyb
       if [ $? -ne 0 ]
       then
         return_code=255
@@ -59,10 +52,10 @@ and ${COL_YELLOW}Kernel signing algorithm RSA-${kernel_keylen}/\
 ${kernel_hashalgo}${COL_STOP}"
           cd ${UTIL_DIR} && ${TEST_DIR}/kernel_image_tests \
             $firmware_algorithmcounter $kernel_algorithmcounter \
-            ${TEST_DIR}/testkeys/key_rsa${firmware_keylen}.pem \
-            ${TEST_DIR}/testkeys/key_rsa${firmware_keylen}.keyb \
-            ${TEST_DIR}/testkeys/key_rsa${kernel_keylen}.pem \
-            ${TEST_DIR}/testkeys/key_rsa${kernel_keylen}.keyb
+            ${TESTKEY_DIR}/key_rsa${firmware_keylen}.pem \
+            ${TESTKEY_DIR}/key_rsa${firmware_keylen}.keyb \
+            ${TESTKEY_DIR}/key_rsa${kernel_keylen}.pem \
+            ${TESTKEY_DIR}/key_rsa${kernel_keylen}.keyb
           if [ $? -ne 0 ]
           then
             return_code=255
@@ -75,20 +68,7 @@ ${kernel_hashalgo}${COL_STOP}"
   done
 }
 
-# Determine script directory.
-if [[ $0 == '/'* ]]; 
-then
-  SCRIPT_DIR="`dirname $0`"
-elif [[ $0 == './'* ]];
-then
-  SCRIPT_DIR="`pwd`"
-else
-  SCRIPT_DIR="`pwd`"/"`dirname $0`"
-fi
-UTIL_DIR=`dirname ${SCRIPT_DIR}`/utils
-KEY_DIR=${SCRIPT_DIR}/testkeys
-TEST_DIR=${SCRIPT_DIR}/
-
+check_test_keys
 echo
 echo "Testing high-level firmware image verification..."
 test_firmware_verification
diff --git a/tests/run_rsa_tests.sh b/tests/run_rsa_tests.sh
index 2439c329f8..a296d13c6a 100755
--- a/tests/run_rsa_tests.sh
+++ b/tests/run_rsa_tests.sh
@@ -3,36 +3,14 @@
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
-
+#
 # Run tests for RSA Signature verification.
 
+# Load common constants and variables.
+. "$(dirname "$0")/common.sh"
+
 return_code=0
-hash_algos=( sha1 sha256 sha512 )
-key_lengths=( 1024 2048 4096 8192 ) 
-TEST_FILE=test_file 
-TEST_FILE_SIZE=1000000
-
-COL_RED='\E[31;1m'
-COL_GREEN='\E[32;1m'
-COL_YELLOW='\E[33;1m'
-COL_BLUE='\E[34;1m'
-COL_STOP='\E[0;m'
-
-# Generate public key signatures on an input file for various combinations
-# of message digest algorithms and RSA key sizes.
-function generate_signatures {
-  algorithmcounter=0
-  for keylen in ${key_lengths[@]}
-  do
-    for hashalgo in ${hash_algos[@]}
-    do
-      ${UTIL_DIR}/signature_digest_utility $algorithmcounter $1 | openssl \
-        rsautl -sign -pkcs -inkey ${KEY_DIR}/key_rsa${keylen}.pem \
-        > $1.rsa${keylen}\_${hashalgo}.sig
-      let algorithmcounter=algorithmcounter+1
-    done
-  done
-}
+TEST_FILE=${TESTCASE_DIR}/test_file
 
 function test_signatures {
   algorithmcounter=0
@@ -42,8 +20,9 @@ function test_signatures {
     do
       echo -e "For ${COL_YELLOW}RSA-$keylen and $hashalgo${COL_STOP}:"
       ${UTIL_DIR}/verify_data $algorithmcounter \
-        ${KEY_DIR}/key_rsa${keylen}.keyb \
-        ${TEST_FILE}.rsa${keylen}_${hashalgo}.sig ${TEST_FILE}
+        ${TESTKEY_DIR}/key_rsa${keylen}.keyb \
+        ${TEST_FILE}.rsa${keylen}_${hashalgo}.sig \
+        ${TEST_FILE}
       if [ $? -ne 0 ]
       then  
         return_code=255
@@ -52,45 +31,12 @@ function test_signatures {
     done
   done
   echo -e "Peforming ${COL_YELLOW}PKCS #1 v1.5 Padding Tests${COL_STOP}..."
-  ${TEST_DIR}/rsa_padding_test ${TEST_DIR}/testkeys/rsa_padding_test_pubkey.keyb
+  ${TEST_DIR}/rsa_padding_test ${TESTKEY_DIR}/rsa_padding_test_pubkey.keyb
 }
 
-function pre_work {
-  # Generate a file with random bytes for signature tests.
-  echo "Generating test file..."
-  dd if=/dev/urandom of=${TEST_FILE} bs=${TEST_FILE_SIZE} count=1
-  echo "Generating signatures..."
-  generate_signatures $TEST_FILE
-}
-
-function cleanup {
-  rm ${SCRIPT_DIR}/${TEST_FILE} ${SCRIPT_DIR}/${TEST_FILE}.*.sig
-}
-
-# Determine script directory.
-if [[ $0 == '/'* ]]; 
-then
-  SCRIPT_DIR="`dirname $0`"
-elif [[ $0 == './'* ]];
-then
-  SCRIPT_DIR="`pwd`"
-else
-  SCRIPT_DIR="`pwd`"/"`dirname $0`"
-fi
-UTIL_DIR=`dirname ${SCRIPT_DIR}`/utils
-KEY_DIR=${SCRIPT_DIR}/testkeys
-TEST_DIR=${SCRIPT_DIR}/
-
-echo "Generating test cases..."
-pre_work
-
-echo
+check_test_keys
 echo "Testing signature verification..."
 test_signatures
 
-echo
-echo "Cleaning up..."
-cleanup
-
 exit $return_code