diff --git a/.uncrustify.cfg b/.uncrustify.cfg
new file mode 100644
index 0000000..ac9173e
--- /dev/null
+++ b/.uncrustify.cfg
@@ -0,0 +1,254 @@
+# Configuration options for Uncrustify specifying the Mbed TLS code style.
+#
+# Note: The code style represented by this file has not yet been introduced
+# to Mbed TLS.
+#
+# Copyright The Mbed TLS Contributors
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+# Line length options
+
+# Wrap lines at 100 characters
+code_width = 100
+
+# Allow splitting long for statements between the condition statements
+ls_for_split_full = true
+
+# Allow splitting function calls between arguments
+ls_func_split_full = true
+
+input_tab_size = 4
+
+# Spaces-only indentation
+indent_with_tabs = 0
+
+indent_columns = 4
+
+# Indent 'case' 1 level from 'switch'
+indent_switch_case = indent_columns
+
+# Line-up strings broken by '\'
+indent_align_string = true
+
+# Braces on the same line (Egyptian-style braces)
+nl_enum_brace = remove
+nl_union_brace = remove
+nl_struct_brace = remove
+nl_do_brace = remove
+nl_if_brace = remove
+nl_for_brace = remove
+nl_else_brace = remove
+nl_while_brace = remove
+nl_switch_brace = remove
+
+# Braces on same line as keywords that follow them - 'else' and the 'while' in 'do {} while ()';
+nl_brace_else = remove
+nl_brace_while = remove
+# Space before else on the same line
+sp_brace_else = add
+# If else is on the same line as '{', force exactly 1 space between them
+sp_else_brace = force
+
+# Functions are the exception and have braces on the next line
+nl_fcall_brace = add
+nl_fdef_brace = add
+
+# Force exactly one space between ')' and '{' in statements
+sp_sparen_brace = force
+
+# At least 1 space around assignment
+sp_assign = add
+
+# Remove spaces around the preprocessor '##' token-concatenate
+sp_pp_concat = ignore
+
+# At least 1 space around '||' and '&&'
+sp_bool = add
+
+# But no space after the '!' operator
+sp_not = remove
+
+# No space after the bitwise-not '~' operator
+sp_inv = remove
+
+# No space after the addressof '&' operator
+sp_addr = remove
+
+# No space around the member '.' and '->' operators
+sp_member = remove
+
+# No space after the dereference '*' operator
+sp_deref = remove
+
+# No space after a unary negation '-'
+sp_sign = remove
+
+# No space between the '++'/'--' operator and its operand
+sp_incdec = remove
+
+# At least 1 space around comparison operators
+sp_compare = add
+
+# Remove spaces inside all kinds of parentheses:
+
+# Remove spaces inside parentheses
+sp_inside_paren = remove
+
+# No spaces inside statement parentheses
+sp_inside_sparen = remove
+
+# No spaces inside cast parentheses '( char )x' -> '(char)x'
+sp_inside_paren_cast = remove
+
+# No spaces inside function parentheses
+sp_inside_fparen = remove
+# (The case where the function has no parameters/arguments)
+sp_inside_fparens = remove
+
+# No spaces inside the first parentheses in a function type
+sp_inside_tparen = remove
+
+# (Uncrustify >= 0.74.0) No spaces inside parens in for statements
+sp_inside_for = remove
+
+# Remove spaces between nested parentheses '( (' -> '(('
+sp_paren_paren = remove
+# (Uncrustify >= 0.74.0)
+sp_sparen_paren = remove
+
+# Remove spaces between ')' and adjacent '('
+sp_cparen_oparen = remove
+
+# (Uncrustify >= 0.73.0) space between 'do' and '{'
+sp_do_brace_open = force
+
+# (Uncrustify >= 0.73.0) space between '}' and 'while'
+sp_brace_close_while = force
+
+# At least 1 space before a '*' pointer star
+sp_before_ptr_star = add
+
+# Remove spaces between pointer stars
+sp_between_ptr_star = remove
+
+# No space after a pointer star
+sp_after_ptr_star = remove
+
+# But allow a space in the case of e.g. char * const x;
+sp_after_ptr_star_qualifier = ignore
+
+# Remove space after star in a function return type
+sp_after_ptr_star_func = remove
+
+# At least 1 space after a type in variable definition etc
+sp_after_type = add
+
+# Force exactly 1 space between a statement keyword (e.g. 'if') and an opening parenthesis
+sp_before_sparen = force
+
+# Remove a space before a ';'
+sp_before_semi = remove
+# (Uncrustify >= 0.73.0) Remove space before a semi in a non-empty for
+sp_before_semi_for = remove
+# (Uncrustify >= 0.73.0) Remove space in empty first statement of a for
+sp_before_semi_for_empty = remove
+# (Uncrustify >= 0.74.0) Remove space in empty middle statement of a for
+sp_between_semi_for_empty = remove
+
+# Add a space after a ';' (unless a comment follows)
+sp_after_semi = add
+# (Uncrustify >= 0.73.0) Add a space after a semi in non-empty for statements
+sp_after_semi_for = add
+# (Uncrustify >= 0.73.0) No space after final semi in empty for statements
+sp_after_semi_for_empty = remove
+
+# Remove spaces on the inside of square brackets '[]'
+sp_inside_square = remove
+
+# Must have at least 1 space after a comma
+sp_after_comma = add
+
+# Must not have a space before a comma
+sp_before_comma = remove
+
+# No space before the ':' in a case statement
+sp_before_case_colon = remove
+
+# No space after a cast - '(char) x' -> '(char)x'
+sp_after_cast = remove
+
+# No space between 'sizeof' and '('
+sp_sizeof_paren = remove
+
+# At least 1 space inside '{ }'
+sp_inside_braces = add
+
+# At least 1 space inside '{ }' in an enum
+sp_inside_braces_enum = add
+
+# At least 1 space inside '{ }' in a struct
+sp_inside_braces_struct = add
+
+# At least 1 space between a function return type and the function name
+sp_type_func = add
+
+# No space between a function name and its arguments/parameters
+sp_func_proto_paren = remove
+sp_func_def_paren = remove
+sp_func_call_paren = remove
+
+# No space between '__attribute__' and '('
+sp_attribute_paren = remove
+
+# No space between 'defined' and '(' in preprocessor conditions
+sp_defined_paren = remove
+
+# At least 1 space between a macro's name and its definition
+sp_macro = add
+sp_macro_func = add
+
+# Force exactly 1 space between a '}' and the name of a typedef if on the same line
+sp_brace_typedef = force
+
+# At least 1 space before a '\' line continuation
+sp_before_nl_cont = add
+
+# At least 1 space around '?' and ':' in ternary statements
+sp_cond_colon = add
+sp_cond_question = add
+
+# Space between #else/#endif and comment afterwards
+sp_endif_cmt = add
+
+# Remove newlines at the start of a file
+nl_start_of_file = remove
+
+# At least 1 newline at the end of a file
+nl_end_of_file = add
+nl_end_of_file_min = 1
+
+# Add braces in single-line statements
+mod_full_brace_do = add
+mod_full_brace_for = add
+mod_full_brace_if = add
+mod_full_brace_while = add
+
+# Remove parentheses from return statements
+mod_paren_on_return = remove
+
+# Disable removal of leading spaces in a multi-line comment if the first and
+# last lines are the same length
+cmt_multi_check_last = false
diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index 7ae1ff9..f1b00f2 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -28,6 +28,7 @@
 #ifndef MBEDTLS_CHECK_CONFIG_H
 #define MBEDTLS_CHECK_CONFIG_H
 
+/* *INDENT-OFF* */
 /*
  * We assume CHAR_BIT is 8 in many places. In practice, this is true on our
  * target platforms, so not an issue, but let's just be extra sure.
@@ -955,4 +956,5 @@
  */
 typedef int mbedtls_iso_c_forbids_empty_translation_units;
 
+/* *INDENT-ON* */
 #endif /* MBEDTLS_CHECK_CONFIG_H */
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 0563c0b..8efccce 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -1363,10 +1363,6 @@
 #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
     for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
         for( i = 0; ciphersuites[i] != 0; i++ )
-#else
-    for( i = 0; ciphersuites[i] != 0; i++ )
-        for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
-#endif
         {
             if( p[0] != 0 ||
                 MBEDTLS_GET_UINT16_BE(p, 1) != ciphersuites[i] )
@@ -1381,6 +1377,24 @@
             if( ciphersuite_info != NULL )
                 goto have_ciphersuite_v2;
         }
+#else
+    for( i = 0; ciphersuites[i] != 0; i++ )
+        for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
+        {
+            if( p[0] != 0 ||
+                MBEDTLS_GET_UINT16_BE(p, 1) != ciphersuites[i] )
+                continue;
+
+            got_common_suite = 1;
+
+            if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
+                                               &ciphersuite_info ) ) != 0 )
+                return( ret );
+
+            if( ciphersuite_info != NULL )
+                goto have_ciphersuite_v2;
+        }
+#endif
 
     if( got_common_suite )
     {
@@ -2233,10 +2247,6 @@
 #if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
     for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
         for( i = 0; ciphersuites[i] != 0; i++ )
-#else
-    for( i = 0; ciphersuites[i] != 0; i++ )
-        for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
-#endif
         {
             if( MBEDTLS_GET_UINT16_BE(p, 0) != ciphersuites[i] )
                 continue;
@@ -2250,6 +2260,23 @@
             if( ciphersuite_info != NULL )
                 goto have_ciphersuite;
         }
+#else
+    for( i = 0; ciphersuites[i] != 0; i++ )
+        for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
+        {
+            if( MBEDTLS_GET_UINT16_BE(p, 0) != ciphersuites[i] )
+                continue;
+
+            got_common_suite = 1;
+
+            if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
+                                               &ciphersuite_info ) ) != 0 )
+                return( ret );
+
+            if( ciphersuite_info != NULL )
+                goto have_ciphersuite;
+        }
+#endif
 
     if( got_common_suite )
     {
diff --git a/programs/psa/key_ladder_demo.c b/programs/psa/key_ladder_demo.c
index 5d64349..bc1cd12 100644
--- a/programs/psa/key_ladder_demo.c
+++ b/programs/psa/key_ladder_demo.c
@@ -704,4 +704,6 @@
     usage( );
     return( EXIT_FAILURE );
 }
-#endif /* MBEDTLS_SHA256_C && MBEDTLS_MD_C && MBEDTLS_AES_C && MBEDTLS_CCM_C && MBEDTLS_PSA_CRYPTO_C && MBEDTLS_FS_IO */
+#endif /* MBEDTLS_SHA256_C && MBEDTLS_MD_C &&
+          MBEDTLS_AES_C && MBEDTLS_CCM_C &&
+          MBEDTLS_PSA_CRYPTO_C && MBEDTLS_FS_IO */
diff --git a/scripts/code_style.py b/scripts/code_style.py
new file mode 100755
index 0000000..68cd556
--- /dev/null
+++ b/scripts/code_style.py
@@ -0,0 +1,158 @@
+#!/usr/bin/env python3
+"""Check or fix the code style by running Uncrustify.
+
+Note: The code style enforced by this script is not yet introduced to
+Mbed TLS. At present this script will only be used to prepare for a future
+change of code style.
+"""
+# Copyright The Mbed TLS Contributors
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import argparse
+import io
+import os
+import subprocess
+import sys
+from typing import List
+
+UNCRUSTIFY_SUPPORTED_VERSION = "0.75.1"
+CONFIG_FILE = ".uncrustify.cfg"
+UNCRUSTIFY_EXE = "uncrustify"
+UNCRUSTIFY_ARGS = ["-c", CONFIG_FILE]
+STDOUT_UTF8 = io.TextIOWrapper(sys.stdout.buffer, encoding='utf-8')
+STDERR_UTF8 = io.TextIOWrapper(sys.stderr.buffer, encoding='utf-8')
+
+def print_err(*args):
+    print("Error: ", *args, file=STDERR_UTF8)
+
+def get_src_files() -> List[str]:
+    """
+    Use git ls-files to get a list of the source files
+    """
+    git_ls_files_cmd = ["git", "ls-files",
+                        "*.[hc]",
+                        "tests/suites/*.function",
+                        "scripts/data_files/*.fmt"]
+
+    result = subprocess.run(git_ls_files_cmd, stdout=subprocess.PIPE, \
+            stderr=STDERR_UTF8, check=False)
+
+    if result.returncode != 0:
+        print_err("git ls-files returned: " + str(result.returncode))
+        return []
+    else:
+        src_files = str(result.stdout, "utf-8").split()
+        # Don't correct style for files in 3rdparty/
+        src_files = list(filter( \
+                lambda filename: not filename.startswith("3rdparty/"), \
+                src_files))
+        return src_files
+
+def get_uncrustify_version() -> str:
+    """
+    Get the version string from Uncrustify
+    """
+    result = subprocess.run([UNCRUSTIFY_EXE, "--version"], \
+            stdout=subprocess.PIPE, stderr=subprocess.PIPE, check=False)
+    if result.returncode != 0:
+        print_err("Could not get Uncrustify version:", str(result.stderr, "utf-8"))
+        return ""
+    else:
+        return str(result.stdout, "utf-8")
+
+def check_style_is_correct(src_file_list: List[str]) -> bool:
+    """
+    Check the code style and output a diff for each file whose style is
+    incorrect.
+    """
+    style_correct = True
+    for src_file in src_file_list:
+        uncrustify_cmd = [UNCRUSTIFY_EXE] + UNCRUSTIFY_ARGS + [src_file]
+        subprocess.run(uncrustify_cmd, stdout=subprocess.PIPE, \
+                stderr=subprocess.PIPE, check=False)
+
+        # Uncrustify makes changes to the code and places the result in a new
+        # file with the extension ".uncrustify". To get the changes (if any)
+        # simply diff the 2 files.
+        diff_cmd = ["diff", "-u", src_file, src_file + ".uncrustify"]
+        result = subprocess.run(diff_cmd, stdout=subprocess.PIPE, \
+                stderr=STDERR_UTF8, check=False)
+        if len(result.stdout) > 0:
+            print(src_file + " - Incorrect code style.", file=STDOUT_UTF8)
+            print("File changed - diff:", file=STDOUT_UTF8)
+            print(str(result.stdout, "utf-8"), file=STDOUT_UTF8)
+            style_correct = False
+        else:
+            print(src_file + " - OK.", file=STDOUT_UTF8)
+
+        # Tidy up artifact
+        os.remove(src_file + ".uncrustify")
+
+    return style_correct
+
+def fix_style_single_pass(src_file_list: List[str]) -> None:
+    """
+    Run Uncrustify once over the source files.
+    """
+    code_change_args = UNCRUSTIFY_ARGS + ["--no-backup"]
+    for src_file in src_file_list:
+        uncrustify_cmd = [UNCRUSTIFY_EXE] + code_change_args + [src_file]
+        subprocess.run(uncrustify_cmd, check=False, stdout=STDOUT_UTF8, \
+                stderr=STDERR_UTF8)
+
+def fix_style(src_file_list: List[str]) -> int:
+    """
+    Fix the code style. This takes 2 passes of Uncrustify.
+    """
+    fix_style_single_pass(src_file_list)
+    fix_style_single_pass(src_file_list)
+
+    # Guard against future changes that cause the codebase to require
+    # more passes.
+    if not check_style_is_correct(src_file_list):
+        print("Code style still incorrect after second run of Uncrustify.")
+        return 1
+    else:
+        return 0
+
+def main() -> int:
+    """
+    Main with command line arguments.
+    """
+    uncrustify_version = get_uncrustify_version().strip()
+    if UNCRUSTIFY_SUPPORTED_VERSION not in uncrustify_version:
+        print("Warning: Using unsupported Uncrustify version '" \
+                + uncrustify_version + "' (Note: The only supported version" \
+                "is " + UNCRUSTIFY_SUPPORTED_VERSION + ")", file=STDOUT_UTF8)
+
+    src_files = get_src_files()
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-f', '--fix', action='store_true', \
+            help='modify source files to fix the code style')
+
+    args = parser.parse_args()
+
+    if args.fix:
+        # Fix mode
+        return fix_style(src_files)
+    else:
+        # Check mode
+        if check_style_is_correct(src_files):
+            return 0
+        else:
+            return 1
+
+if __name__ == '__main__':
+    sys.exit(main())
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 3426cf1..992e3b3 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -3353,6 +3353,26 @@
     [ "$ver_major" -eq 3 ] && [ "$ver_minor" -ge 10 ]
 }
 
+component_test_corrected_code_style () {
+    ./scripts/code_style.py --fix
+
+    msg "build: make, default config (out-of-box), corrected code style"
+    make
+
+    msg "test: main suites make, default config (out-of-box), corrected code style"
+    make test
+
+    # Clean up code-style corrections
+    git checkout -- .
+}
+
+support_test_corrected_code_style() {
+    case $(uncrustify --version) in
+        *0.75.1*) true;;
+        *) false;;
+    esac
+}
+
 component_check_python_files () {
     msg "Lint: Python scripts"
     tests/scripts/check-python-files.sh