diff --git a/scripts/imgtool/main.py b/scripts/imgtool/main.py
new file mode 100755
index 0000000..1917a97
--- /dev/null
+++ b/scripts/imgtool/main.py
@@ -0,0 +1,201 @@
+#! /usr/bin/env python3
+#
+# Copyright 2017 Linaro Limited
+#
+# 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 click
+import getpass
+import imgtool.keys as keys
+from imgtool import image
+from imgtool.version import decode_version
+
+
+def gen_rsa2048(keyfile, passwd):
+    keys.RSA2048.generate().export_private(path=keyfile, passwd=passwd)
+
+
+def gen_ecdsa_p256(keyfile, passwd):
+    keys.ECDSA256P1.generate().export_private(keyfile, passwd=passwd)
+
+
+def gen_ecdsa_p224(keyfile, passwd):
+    print("TODO: p-224 not yet implemented")
+
+
+valid_langs = ['c', 'rust']
+keygens = {
+    'rsa-2048':   gen_rsa2048,
+    'ecdsa-p256': gen_ecdsa_p256,
+    'ecdsa-p224': gen_ecdsa_p224,
+}
+
+
+def load_key(keyfile):
+    # TODO: better handling of invalid pass-phrase
+    key = keys.load(keyfile)
+    if key is not None:
+        return key
+    passwd = getpass.getpass("Enter key passphrase: ").encode('utf-8')
+    return keys.load(keyfile, passwd)
+
+
+def get_password():
+    while True:
+        passwd = getpass.getpass("Enter key passphrase: ")
+        passwd2 = getpass.getpass("Reenter passphrase: ")
+        if passwd == passwd2:
+            break
+        print("Passwords do not match, try again")
+
+    # Password must be bytes, always use UTF-8 for consistent
+    # encoding.
+    return passwd.encode('utf-8')
+
+
+@click.option('-p', '--password', is_flag=True,
+              help='Prompt for password to protect key')
+@click.option('-t', '--type', metavar='type', required=True,
+              type=click.Choice(keygens.keys()))
+@click.option('-k', '--key', metavar='filename', required=True)
+@click.command(help='Generate pub/private keypair')
+def keygen(type, key, password):
+    password = get_password() if password else None
+    keygens[type](key, password)
+
+
+@click.option('-l', '--lang', metavar='lang', default=valid_langs[0],
+              type=click.Choice(valid_langs))
+@click.option('-k', '--key', metavar='filename', required=True)
+@click.command(help='Get public key from keypair')
+def getpub(key, lang):
+    key = load_key(key)
+    if key is None:
+        print("Invalid passphrase")
+    elif lang == 'c':
+        key.emit_c()
+    elif lang == 'rust':
+        key.emit_rust()
+    else:
+        raise ValueError("BUG: should never get here!")
+
+
+def validate_version(ctx, param, value):
+    try:
+        decode_version(value)
+        return value
+    except ValueError as e:
+        raise click.BadParameter("{}".format(e))
+
+
+def validate_header_size(ctx, param, value):
+    min_hdr_size = image.IMAGE_HEADER_SIZE
+    if value < min_hdr_size:
+        raise click.BadParameter(
+            "Minimum value for -H/--header-size is {}".format(min_hdr_size))
+    return value
+
+
+class BasedIntParamType(click.ParamType):
+    name = 'integer'
+
+    def convert(self, value, param, ctx):
+        try:
+            if value[:2].lower() == '0x':
+                return int(value[2:], 16)
+            elif value[:1] == '0':
+                return int(value, 8)
+            return int(value, 10)
+        except ValueError:
+            self.fail('%s is not a valid integer' % value, param, ctx)
+
+
+@click.argument('outfile')
+@click.argument('infile')
+@click.option('-E', '--encrypt', metavar='filename',
+              help='Encrypt image using the provided public key')
+@click.option('-e', '--endian', type=click.Choice(['little', 'big']),
+              default='little', help="Select little or big endian")
+@click.option('--overwrite-only', default=False, is_flag=True,
+              help='Use overwrite-only instead of swap upgrades')
+@click.option('-M', '--max-sectors', type=int,
+              help='When padding allow for this amount of sectors (defaults to 128)')
+@click.option('--pad', default=False, is_flag=True,
+              help='Pad image to --slot-size bytes, adding trailer magic')
+@click.option('-S', '--slot-size', type=BasedIntParamType(), required=True,
+              help='Size of the slot where the image will be written')
+@click.option('--pad-header', default=False, is_flag=True,
+              help='Add --header-size zeroed bytes at the beginning of the image')
+@click.option('-H', '--header-size', callback=validate_header_size,
+              type=BasedIntParamType(), required=True)
+@click.option('-v', '--version', callback=validate_version,  required=True)
+@click.option('--align', type=click.Choice(['1', '2', '4', '8']),
+              required=True)
+@click.option('-k', '--key', metavar='filename')
+@click.command(help='Create a signed or unsigned image')
+def sign(key, align, version, header_size, pad_header, slot_size, pad,
+         max_sectors, overwrite_only, endian, encrypt, infile, outfile):
+    img = image.Image.load(infile, version=decode_version(version),
+                           header_size=header_size, pad_header=pad_header,
+                           pad=pad, align=int(align), slot_size=slot_size,
+                           max_sectors=max_sectors,
+                           overwrite_only=overwrite_only,
+                           endian=endian)
+    key = load_key(key) if key else None
+    enckey = load_key(encrypt) if encrypt else None
+    if enckey:
+        if not isinstance(enckey, (keys.RSA2048, keys.RSA2048Public)):
+            raise Exception("Encryption only available with RSA")
+        if key and not isinstance(key, (keys.RSA2048, keys.RSA2048Public)):
+            raise Exception("Encryption with sign only available with RSA")
+    img.create(key, enckey)
+
+    if pad:
+        img.pad_to(slot_size)
+
+    img.save(outfile)
+
+
+class AliasesGroup(click.Group):
+
+    _aliases = {
+        "create": "sign",
+    }
+
+    def list_commands(self, ctx):
+        cmds = [k for k in self.commands]
+        aliases = [k for k in self._aliases]
+        return sorted(cmds + aliases)
+
+    def get_command(self, ctx, cmd_name):
+        rv = click.Group.get_command(self, ctx, cmd_name)
+        if rv is not None:
+            return rv
+        if cmd_name in self._aliases:
+            return click.Group.get_command(self, ctx, self._aliases[cmd_name])
+        return None
+
+
+@click.command(cls=AliasesGroup,
+               context_settings=dict(help_option_names=['-h', '--help']))
+def imgtool():
+    pass
+
+
+imgtool.add_command(keygen)
+imgtool.add_command(getpub)
+imgtool.add_command(sign)
+
+
+if __name__ == '__main__':
+    imgtool()