diff --git a/archive.py b/archive.py
new file mode 100644
index 0000000..7f2bd68
--- /dev/null
+++ b/archive.py
@@ -0,0 +1,137 @@
+from datetime import datetime
+from email.message import Message
+import hashlib
+import os
+import shutil
+import subprocess
+import tempfile
+
+from test import MailTest
+
+
+def find(cnt):
+    data, login = cnt
+    def found(data):
+        mime = data.get_content_type()
+        if mime == "application/octet-stream":
+            mime = _guess_mime(data.get_payload(decode=True))
+        if mime == "application/x-xz":
+            fname = data.get_filename(login + ".tar.xz")
+        elif mime == "application/x-bzip" or mime == "application/x-bzip2":
+            fname = data.get_filename(login + ".tar.bz2")
+        elif mime == "application/x-gzip" or mime == "application/gzip":
+            fname = data.get_filename(login + ".tar.gz")
+        elif mime == "application/zip":
+            fname = data.get_filename(login + ".zip")
+        elif mime == "application/rar":
+            fname = data.get_filename(login + ".rar")
+        elif mime == "application/x-tar" or mime == "application/tar":
+            fname = data.get_filename(login + ".tar")
+        else:
+            fname = None
+        return data.get_payload(decode=True), fname
+
+    if isinstance(data, Message):
+        if not data.is_multipart():
+            data, fname = found(data)
+            yield MailTest("Tarball found: %s." % fname, -1)
+        else:
+            for part in data.walk():
+                data, fname = found(part)
+                if fname is not None:
+                    yield MailTest("Tarball found: %s." % fname, -1)
+                    break
+    yield (data, login)
+
+
+def hash_archive(cnt, dest=None):
+    data, login = cnt
+    sha = hashlib.sha1(data.encode() if isinstance(data, str) else data).hexdigest()
+    yield MailTest("Your tarball SHA-1 is %s." % sha, -1)
+    if dest is not None and os.path.exists(os.path.join(dest, login + "." + sha)):
+        yield MailTest("You have already uploaded this tarball.", 1)
+        yield False
+    else:
+        yield (data, sha, login)
+
+
+def _guess_mime(data):
+    with subprocess.Popen(["file",
+                           "--brief",
+                           "--mime-type",
+                           "-"], env={"LANG": 'C'}, stdin=subprocess.PIPE, stdout=subprocess.PIPE) as p:
+        p.stdin.write(data.encode() if isinstance(data, str) else data)
+        p.stdin.close()
+        p.wait()
+        if p.returncode == 0:
+            return p.stdout.read().decode().strip()
+
+
+def guess_mime(cnt):
+    data, sha, login = cnt
+
+    mime = _guess_mime(data)
+    if mime is not None:
+        yield MailTest("Guessed content-type of your submission: %s." % mime,
+                       0 if mime.find("application/x-") == 0 else 2)
+    else:
+        mime = "application/x-tar"
+        yield MailTest("Unable to guess content-type of your submission. Assuming: %s." % mime)
+
+    yield data, mime, sha, login
+
+
+def extract(cnt, dest=None):
+    data, type, sha, login = cnt
+
+    if dest is not None:
+        odest = dest
+        os.makedirs(odest, exist_ok=True)
+        ldest = os.path.join(dest, login)
+        dest = os.path.join(dest, login + "." + sha)
+        if os.path.exists(dest):
+            yield MailTest("You have already uploaded this tarball.", 1)
+            return
+        last_dest = os.readlink(ldest) if os.path.exists(ldest) else None
+
+    try:
+        with tempfile.TemporaryDirectory() as temp:
+            with subprocess.Popen(["tar", "--no-same-owner", "--no-same-permissions",
+                                   ("-xvC" + temp) if dest is not None else "-t",
+                                   "-z" if type == "application/x-gzip" else "",
+                                   "-J" if type == "application/x-xz" else "",
+                                   "-j" if type in ["application/x-bzip", "application/x-bzip2"] else "",
+                                   "-"], env={"LANG": 'C'}, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE) as p:
+                p.stdin.write(data.encode() if isinstance(data, str) else data)
+                p.stdin.close()
+                p.wait()
+                err = p.stdout.read().decode()
+                err += p.stderr.read().decode()
+                if p.returncode == 0:
+                    if dest is not None:
+                        nsub = len([x for x in os.listdir(odest) if x.find(os.path.basename(ldest) + ".") == 0]) + 1
+                        if nsub > 1:
+                            yield MailTest("This is your %i%s submission. Last submission on: %s" % (nsub, "st" if nsub == 0 else ("nd" if nsub == 1 else ("rd" if nsub == 3 else "th")), datetime.fromtimestamp(int(os.lstat(ldest).st_mtime))), -1)
+                        else:
+                            yield MailTest("This is your %i%s submission." % (nsub, "st" if nsub == 1 else ("nd" if nsub == 2 else ("rd" if nsub == 3 else "th"))), -1)
+                        if dest != ldest:
+                            if os.path.lexists(ldest):
+                                os.remove(ldest)
+                            os.symlink(os.path.basename(dest), ldest)
+                        if len(os.listdir(temp)) == 1:
+                            shutil.move(os.path.join(temp, os.listdir(temp)[0]), dest)
+                        else:
+                            shutil.move(temp, dest)
+                    yield MailTest("Archive successfully extracted.", details=err)
+                    yield dest
+                else:
+                    yield MailTest("An error occured during archive extraction:", 1, details=err)
+
+                if not os.path.exists(temp):
+                    os.makedirs(temp)
+    except PermissionError:
+        if os.path.lexists(ldest):
+            os.remove(ldest)
+        if last_dest is not None:
+            os.symlink(last_dest, ldest)
+        yield MailTest("Your archive's content has crazy permissions. Please fix it.", 1)
diff --git a/check.py b/check.py
new file mode 100755
index 0000000..fb21b2c
--- /dev/null
+++ b/check.py
@@ -0,0 +1,229 @@
+#!/usr/bin/env python3
+
+from datetime import datetime
+import email
+import os
+import sys
+import stat
+import subprocess
+
+GNUPG_DIRECTORY = "~/.gnupg-checker"
+SOFT_MAX_SUBMISSION = None
+HARD_MAX_SUBMISSION = None
+FROM = "Automatic VIRLI Mail Checker <virli@nemunai.re>"
+SEND_TO_REALUSER = False
+BETA = False
+ALTERNATE_RESOLUTIONS = False
+
+
+import archive
+import envelope
+import late
+import login
+import signature
+from test import MailTest
+
+def signcheck(data):
+    yield MailTest("Those tests are limited to signature checking. THIS IS NOT THE SUBMISSION INTERFACE.", 2)
+    yield data
+
+
+def gen_checks(submissions_dir, check_content=False):
+    if HARD_MAX_SUBMISSION is not None and check_content:
+        yield (late.check, [HARD_MAX_SUBMISSION, SOFT_MAX_SUBMISSION])
+    else:
+        yield signcheck
+    yield (envelope.check, [GNUPG_DIRECTORY, BETA])
+    yield (signature.check, [GNUPG_DIRECTORY])
+    yield (login.check, ["/home/nemunaire/workspace/check_mail/SRS2017.csv"])
+    if check_content:
+        yield archive.find
+        yield ( archive.hash_archive, [submissions_dir] )
+        yield archive.guess_mime
+        yield ( archive.extract, [submissions_dir] )
+
+
+def respondmail(to, subject, ref, checks):
+    from email.message import EmailMessage
+
+    if not isinstance(checks, list):
+        checks = [c for c in checks]
+
+    # Show only the first message if there is one ACCEPT
+    if len(checks) > 1 and not (ALTERNATE_RESOLUTIONS and BETA):
+        maxitem = checks[0]
+        for item in checks:
+            lvl, tests, final_decision = item
+            if maxitem[0] < lvl:
+                maxitem = item
+            if final_decision == "ACCEPT" or final_decision == "SKIP":
+                return respondmail(to, subject, ref, [(lvl, tests, final_decision)])
+        # Display the most upper error
+        if not ALTERNATE_RESOLUTIONS:
+            return respondmail(to, subject, ref, [maxitem])
+
+    msg = EmailMessage()
+    msg["X-loop"] = "virli"
+    msg["From"] = FROM
+    msg["To"] = to
+    if ref is not None:
+        msg["References"] = ref
+        msg["In-Reply-To"] = ref
+    msg["Subject"] = ("Re: " if not subject.lower().find("re: ") >= 0 else "") + subject
+
+    test = None
+    final_decision = "REJECT"
+    fmt = ""
+    for lvl, tests, final_decision in checks:
+        if fmt != "":
+            fmt += '\n============ There is also another resolution: ============\n\n'
+        for test in tests:
+            fmt += test.valuestr
+            fmt += test.title
+            fmt += '\n'
+        if test is not None and test.details is not None and test.details != "":
+            fmt += '\n'
+            fmt += test.details.strip()
+            fmt += '\n'
+
+    if final_decision == "SKIP":
+        fmt += '\nI stopped here the email analysis.'
+    else:
+        fmt += '\nAfter analyzing your e-mail, I\'ve decided to ' + final_decision + ' it.'
+
+    msg.set_content("""Hi!
+
+This is the automatic e-mail analyzer in charge of checking your work.
+
+Here is the detailed report for your submission:
+
+""" + fmt + """
+
+Sincerely,
+
+-- \nAutomatic e-mail checker
+running for nemunaire@nemunai.re""")
+
+    import smtplib
+    with smtplib.SMTP("localhost") as smtp:
+        if SEND_TO_REALUSER:
+            smtp.send_message(msg)
+            smtp.send_message(msg, to_addrs=["virli-report@nemunai.re"])
+        else:
+            print(msg.as_string())
+
+
+def readmail(fp):
+    cnt = email.message_from_binary_file(fp)
+    frm = cnt.get("From") or "someone"
+    subject = cnt.get("Subject") or "your mail"
+    ref = cnt.get("Message-ID") or ""
+
+    return cnt, frm, subject, ref
+
+
+def check_mail(cnt, submissions_dir, check_content=False):
+    results = []
+
+    # sentinel
+    results.append([(None, [cnt])])
+
+    lvl = 0
+    for check in gen_checks(submissions_dir=submissions_dir, check_content=check_content):
+        lvl += 1
+        curr = []
+        curc = []
+
+        for parent in range(len(results[-1])):
+            cnt = results[-1][parent][1][-1]
+
+            if cnt is True or cnt is None or cnt is False:
+                res = []
+                for i in range(len(results) - 1, 0, -1):
+                    for m in reversed(results[i][parent][1][:-1]):
+                        res.append(m)
+                    parent = results[i][parent][0]
+                res.reverse()
+                if cnt is None: final = "REJECT"
+                elif cnt is False: final = "SKIP"
+                else: final = "ACCEPT"
+                yield lvl, res, final
+                continue
+
+            if isinstance(check, tuple):
+                chk, params = check
+                res = chk(cnt, *params)
+            else:
+                res = check(cnt)
+
+            for r in res:
+                curc.append(r)
+                if not isinstance(r, MailTest):
+                    curr.append((parent, curc))
+                    curc = []
+
+            if len(curc) > 0:
+                curc.append(None)
+                curr.append((parent, curc))
+                curc = []
+        results.append(curr)
+
+    for parent in range(len(results[-1])):
+        res = []
+        cnt = results[-1][parent][1][-1]
+        for i in range(len(results) - 1, 0, -1):
+            for m in reversed(results[i][parent][1][:-1]):
+                res.append(m)
+            parent = results[i][parent][0]
+        res.reverse()
+        if cnt is None: final = "REJECT"
+        elif cnt is False: final = "SKIP"
+        else: final = "ACCEPT"
+        yield len(results), res, final
+
+
+if __name__ == '__main__':
+    os.umask(~(stat.S_IRUSR | stat.S_IWUSR | stat.S_IXUSR))
+    GNUPG_DIRECTORY = os.path.expanduser(GNUPG_DIRECTORY)
+    if not os.path.isdir(GNUPG_DIRECTORY):
+        os.mkdir(GNUPG_DIRECTORY)
+
+    # Parse command line arguments
+    import argparse
+    parser = argparse.ArgumentParser()
+
+    parser.add_argument("-s", "--sign", action="store_true",
+                        help="limit check to signature")
+
+    parser.add_argument("--real-send", action="store_true",
+                        help="Effectively sent mail to real users")
+
+    parser.add_argument('--soft-max-submission', default="thursday 8:42",
+                        help="allow submission until this hour")
+
+    parser.add_argument('--hard-max-submission', default="thursday 9:21",
+                        help="allow submission until this hour")
+
+    parser.add_argument('--submissions', default="/tmp/rendus",
+                        help="directory where store submissions")
+
+    parser.add_argument('--beta', action="store_true",
+                        help="enable beta features")
+
+    parser.add_argument('--alternate-resolutions', action="store_true",
+                        help="enable if you want to display alternate resolutions")
+
+    args = parser.parse_args()
+
+    with subprocess.Popen(["date", "-d", args.soft_max_submission, "-u", "-Iseconds"], stdout=subprocess.PIPE) as f:
+        SOFT_MAX_SUBMISSION = datetime.strptime(f.stdout.read().strip().decode(), "%Y-%m-%dT%H:%M:%S%z")
+
+    with subprocess.Popen(["date", "-d", args.hard_max_submission, "-u", "-Iseconds"], stdout=subprocess.PIPE) as f:
+        HARD_MAX_SUBMISSION = datetime.strptime(f.stdout.read().strip().decode(), "%Y-%m-%dT%H:%M:%S%z")
+
+    ALTERNATE_RESOLUTIONS = args.alternate_resolutions
+    SEND_TO_REALUSER = args.real_send
+    BETA = args.beta
+
+    cnt, frm, subject, ref = readmail(sys.stdin.buffer)
+    respondmail(frm, subject, ref, [c for c in check_mail(cnt, submissions_dir=args.submissions, check_content=not args.sign)])
diff --git a/envelope.py b/envelope.py
new file mode 100644
index 0000000..888f544
--- /dev/null
+++ b/envelope.py
@@ -0,0 +1,94 @@
+import re
+import subprocess
+
+from test import MailTest
+
+
+def import_pubkey(key, GNUPG_DIRECTORY):
+    with subprocess.Popen(["gpg",
+                           "--homedir=" + GNUPG_DIRECTORY,
+                           "--batch",
+                           "--import",
+                           "-"], env={"LANG": 'C'}, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE) as p:
+        p.stdin.write(key)
+        p.stdin.close()
+        p.wait()
+        gpg_output = p.stderr.read().decode()
+        if p.returncode == 0:
+            yield MailTest("New PGP key successfully imported:", details=gpg_output)
+            yield False
+        else:
+            yield MailTest("An error occurs during PGP key importation:", details=gpg_output)
+
+
+def assume_rfc3156(msg):
+    if msg.get_param("protocol") is None or msg.get_param("protocol") != "application/pgp-signature" or msg.get_payload(1).get_content_type() != "application/pgp-signature":
+        yield MailTest("Message treated as RFC3156 due to Content-Type, but is not compliant", 1)
+        return
+
+    # Extracting signature
+    try:
+        data = msg.get_payload(0)
+        sign = msg.get_payload(1).get_payload().encode()
+
+        # Except an exception in the two above lines if one part doesn't exist
+        yield MailTest("Message treated as RFC3156: content and signature found")
+
+        yield (data, sign)
+
+    except IndexError:
+        yield MailTest("Message treated as RFC3156 due to Content-Type, but is not compliant", 1)
+        return
+
+
+def assume_oldstyle(payload):
+    yield MailTest("Found BEGIN PGP SIGNED MESSAGE: message treated as old style PGP email.")
+    yield payload
+
+
+
+def check(msg, GNUPG_DIRECTORY, beta=False):
+    ct = msg.get_content_type()
+
+    # First, looking for public key
+    for part in msg.walk():
+        if part.get_content_type() == "application/pgp-keys":
+            yield from import_pubkey(part.get_payload(decode=True), GNUPG_DIRECTORY)
+            return
+
+    if ct == "multipart/signed" and msg.is_multipart():
+        yield from assume_rfc3156(msg)
+
+    else:
+        yield MailTest("This is not a signed e-mail: %s." % ct, 1)
+
+        if ct == "multipart/encrypted":
+            yield MailTest("As an automated service, I can't access my owner's private key. Please resend your email, unencrypted but signed.", -1)
+            return
+
+        from archive import _guess_mime
+
+        # Looking for signed content
+        for part in msg.walk():
+            payload = part.get_payload()
+            if part.get_content_type() == "application/pgp-signature":
+                p = [x for x in msg.walk()]
+                for s in range(len(p) - 1, -1, -1):
+                    spart = p[s]
+                    if part is not spart and not spart.is_multipart():
+                        yield MailTest("Separate signature found. Trying it with part %d (%s) ..." % (s, spart.get_content_type()), -1)
+                        yield (spart.get_payload(decode=True), part.get_payload(decode=True))
+
+            elif beta and part.get_content_type() == "application/octet-stream":
+                yield MailTest("Entering BETA feature of walking through mail part, looking for a submission.", 2)
+                print(_guess_mime(part.get_payload(decode=True)))
+                yield from check_binary(part.as_bytes() if part.is_multipart() else part.get_payload(decode=True))
+
+            elif payload is not None and not part.is_multipart() and part.get_payload(decode=True).find(b"-----BEGIN PGP SIGNED MESSAGE-----") >= 0:
+                res = re.match(".*(-----BEGIN PGP SIGNED MESSAGE-----(.*)-----BEGIN PGP SIGNATURE-----(.*)-----END PGP SIGNATURE-----).*", payload, re.DOTALL)
+                if res is not None:
+                    yield from assume_oldstyle(payload)
+                else:
+                    res = re.match(b".*(-----BEGIN PGP SIGNED MESSAGE-----(.*)-----BEGIN PGP SIGNATURE-----(.*)-----END PGP SIGNATURE-----).*", part.get_payload(decode=True), re.DOTALL)
+                    if res is not None:
+                        yield from assume_oldstyle(part.get_payload(decode=True))
diff --git a/gpg_status_parser.py b/gpg_status_parser.py
new file mode 100644
index 0000000..9e67f7d
--- /dev/null
+++ b/gpg_status_parser.py
@@ -0,0 +1,157 @@
+import re
+
+class GoodSignature:
+
+    def __init__(self, long_keyid_or_fpr, *username):
+        self.long_keyid_or_fpr = long_keyid_or_fpr
+        self.username = " ".join(username)
+
+
+class ExpiredSignature:
+
+    def __init__(self, long_keyid_or_fpr, *username):
+        self.long_keyid_or_fpr = long_keyid_or_fpr
+        self.username = " ".join(username)
+
+
+class ExpiredKey:
+
+    def __init__(self, long_keyid_or_fpr, *username):
+        self.long_keyid_or_fpr = long_keyid_or_fpr
+        self.username = " ".join(username)
+
+
+class RevokedKey:
+
+    def __init__(self, long_keyid_or_fpr, *username):
+        self.long_keyid_or_fpr = long_keyid_or_fpr
+        self.username = " ".join(username)
+
+
+class BadSignature:
+
+    def __init__(self, long_keyid_or_fpr, *username):
+        self.long_keyid_or_fpr = long_keyid_or_fpr
+        self.username = " ".join(username)
+
+
+class UncheckableSignature:
+
+    def __init__(self, keyid, pkalgo, hashalgo, sig_class, time, rc):
+        self.keyid = keyid
+        self.pkalgo = pkalgo
+        self.hashalgo = hashalgo
+        self.sig_class = sig_class
+        self.time = time
+        self.rc = rc
+
+
+class ValidSignature:
+
+    def __init__(self, fingerprint_in_hex, sig_creation_date, sig_timestamp, expire_timestamp, sig_version, reserved, pubkey_algo, hash_algo, sig_class, primary_key_fpr=None):
+        self.fingerprint_in_hex = fingerprint_in_hex
+        self.sig_creation_date = sig_creation_date
+        self.sig_timestamp = sig_timestamp
+        self.expire_timestamp = expire_timestamp
+        self.sig_version = sig_version
+        self.reserved = reserved
+        self.pubkey_algo = pubkey_algo
+        self.hash_algo = hash_algo
+        self.sig_class = sig_class
+        self.primary_key_fpr = primary_key_fpr
+
+
+class SignatureID:
+
+    def __init__(self, radix64_string, sig_creation_date, sig_timestamp):
+        self.radix64_string = radix64_string
+        self.sig_creation_date = sig_creation_date
+        self.sig_timestamp = sig_timestamp
+
+
+class EncryptedTo:
+
+    def __init__(self, long_keyid, keytype, keylength):
+        self.long_keyid = long_keyid
+        self.keytype = keytype
+        self.keylength = keylength
+
+
+class NoPublicKey:
+
+    def __init__(self, long_keyid):
+        self.long_keyid = long_keyid
+
+
+class _Trust:
+
+    def __init__(self, flag, validation_model=None):
+        self.flag = flag
+        self.validation_model = validation_model
+
+class TrustUndefined(_Trust):
+
+    def __str__(self):
+        return "unknown"
+
+class TrustNever(_Trust):
+
+    def __str__(self):
+        return "never"
+
+class TrustMarginal(_Trust):
+
+    def __str__(self):
+        return "marginal"
+
+class TrustFully(_Trust):
+
+    def __str__(self):
+        return "fully"
+
+class TrustUltimate(_Trust):
+
+    def __str__(self):
+        return "ultimate"
+
+
+_keywords = {
+    "GOODSIG": GoodSignature,
+    "EXPSIG": ExpiredSignature,
+    "EXPKEYSIG": ExpiredKey,
+    "REVKEYSIG": RevokedKey,
+    "BADSIG": BadSignature,
+    "ERRSIG": UncheckableSignature,
+    "VALIDSIG": ValidSignature,
+    "SIG_ID": SignatureID,
+    "ENC_TO": EncryptedTo,
+    "NO_PUBKEY": NoPublicKey,
+
+    "TRUST_UNDEFINED": TrustUndefined,
+    "TRUST_NEVER": TrustNever,
+    "TRUST_MARGINAL": TrustMarginal,
+    "TRUST_FULLY": TrustFully,
+    "TRUST_ULTIMATE": TrustUltimate,
+}
+
+def parse(fd):
+    line = fd.readline()
+    context = {}
+    while line:
+        res = re.match(r"^\[GNUPG:\] (?P<keyword>\S+)(?: (?P<args>.*))?$", line.decode())
+        if res is not None:
+            keyword = res.group("keyword")
+            args = res.group("args").split(" ") if res.group("args") is not None else []
+
+            if keyword == "NEWSIG":
+                if len(context) > 0:
+                    yield context
+                context = {}
+
+            elif keyword in _keywords:
+                if keyword[:5] == "TRUST":
+                    context["TRUST"] = _keywords[keyword](*args)
+                context[keyword] = _keywords[keyword](*args)
+        line = fd.readline()
+
+    yield context
diff --git a/late.py b/late.py
new file mode 100644
index 0000000..4625785
--- /dev/null
+++ b/late.py
@@ -0,0 +1,20 @@
+from datetime import datetime, timezone
+
+from test import MailTest
+
+
+def check(cnt, hard_max_submission_date, soft_max_submission_date=None):
+    if soft_max_submission_date is None:
+        soft_max_submission_date = hard_max_submission_date
+    else:
+        soft_max_submission_date = min(soft_max_submission_date, hard_max_submission_date)
+
+    now = datetime.now().replace(tzinfo=timezone.utc)
+    yield MailTest("We are %s, submission permitted until %s" % (now.strftime("%c"), soft_max_submission_date.strftime("%c")), -1)
+    if now > soft_max_submission_date:
+        discard = now > hard_max_submission_date
+        yield MailTest("Submissions have been closed since %s minute(s)" % int((now - soft_max_submission_date).total_seconds()/60), 1 if discard else 2)
+        if discard:
+            return
+
+    yield cnt
diff --git a/login.py b/login.py
new file mode 100644
index 0000000..54313d4
--- /dev/null
+++ b/login.py
@@ -0,0 +1,19 @@
+import csv
+from email.utils import parseaddr
+
+from test import MailTest
+
+
+def check(cnt, file):
+    data, uname = cnt
+    username, address = parseaddr(uname)
+
+    with open(file, encoding='utf-8') as fd:
+        people = csv.reader(fd)
+        for p in people:
+            if address.lower() == p[4].lower() or uname.lower().find(p[2].lower()) >= 0 or username.lower().replace(" ", "").find(p[0].lower().replace(" ", "")) >= 0 and username.lower().find(p[1].lower()) >= 0:
+                yield MailTest("Recognized as %s: %s %s." % (p[2], p[1], p[0]))
+                yield data, p[2]
+                return
+
+    yield MailTest("The username of your key is not explicit, I can't find you.", 1)
diff --git a/signature.py b/signature.py
new file mode 100644
index 0000000..07222d9
--- /dev/null
+++ b/signature.py
@@ -0,0 +1,128 @@
+from datetime import datetime
+import os
+import tempfile
+import subprocess
+import sys
+
+from test import MailTest
+import gpg_status_parser
+
+
+def verify_sign(data, gpg_rcode, gpg_status, gpg_output=""):
+    if len(gpg_status) != 1:
+        yield MailTest("Too much status, please fill a bug report.", 1, details=gpg_output)
+        return
+
+    ctx = gpg_status[0]
+
+    if gpg_rcode == 0 and "VALIDSIG" in ctx:
+        yield MailTest("Signed with key: 0x%s, on %s" % (ctx["VALIDSIG"].fingerprint_in_hex[24:], datetime.fromtimestamp(int(ctx["VALIDSIG"].sig_timestamp))))
+        if "EXPKEYSIG" in ctx:
+            yield MailTest("Your key has expired.", 1)
+            return
+        if "EXPSIG" in ctx:
+            yield MailTest("The signature has expired.", 1)
+            return
+        if "TRUST_NEVER" in ctx:
+            yield MailTest("Your trust level is %s." % ctx["TRUST_NEVER"], 1)
+            return
+        if "GOODSIG" in ctx:
+            yield MailTest("Signature made by %s%s" % (ctx["GOODSIG"].username, (" [%s]" % ctx["TRUST"]) if "TRUST" in ctx else ""), -1)
+            if "TRUST_UNDEFINED" in ctx:
+                yield MailTest("Your trust level is %s. Consider asking other people to sign your key." % ctx["TRUST_UNDEFINED"], 2)
+            yield data, ctx["GOODSIG"].username
+    else:
+        yield MailTest("Bad signature. Here is the gnupg output:", 1, details=gpg_output.strip())
+
+
+def check(cnt, GNUPG_DIRECTORY):
+    if len(cnt) == 2:
+        yield from check_sep(*cnt, GNUPG_DIRECTORY=GNUPG_DIRECTORY)
+    else:
+        yield from check_merged(cnt, GNUPG_DIRECTORY=GNUPG_DIRECTORY)
+
+
+def check_sep(data, sign, GNUPG_DIRECTORY):
+    gpg_output = ""
+    gpg_status = []
+    gpg_rcode = None
+    try:
+        f = tempfile.NamedTemporaryFile(delete=False)
+        f.write(sign)
+        f.close()
+
+        with subprocess.Popen(["gpg",
+                               "--homedir=" + GNUPG_DIRECTORY,
+                               "--status-fd=1",
+                               "--auto-key-retrieve",
+                               "--auto-key-locate=clear,local,pka,dane,cert,keyserver",
+                               "--keyserver=pool.sks-keyservers.net",
+                               "--quiet",
+                               "--batch",
+                               "--verify",
+                               f.name,
+                               "-"], env={"LANG": 'en_US.UTF-8'}, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE) as p:
+            if isinstance(data, bytes):
+                bdata = data
+            else:
+                bdata = data.as_bytes()
+            if not bdata.find(b'\r\n') >= 0:
+                bdata.replace(b'\n', b'\r\n')  # Windows hack
+            p.stdin.write(bdata)
+            p.stdin.close()
+
+            gpg_status = [l for l in gpg_status_parser.parse(p.stdout)]
+            p.wait()
+            gpg_output = p.stderr.read()
+            gpg_rcode = p.returncode
+
+    except Exception as e:
+        yield MailTest("An error occured: %s" % e, 1)
+        return
+    finally:
+        os.unlink(f.name)
+
+    yield from verify_sign(data, gpg_rcode, gpg_status, gpg_output.decode('utf-8'))
+
+
+def check_merged(bdata, GNUPG_DIRECTORY):
+    f = tempfile.NamedTemporaryFile()
+    f.close()
+
+    gpg_output = ""
+    gpg_status = []
+    gpg_rcode = None
+    try:
+        with subprocess.Popen(["gpg",
+                               "--homedir=" + GNUPG_DIRECTORY,
+                               "--status-fd=1",
+                               "--auto-key-retrieve",
+                               "--auto-key-locate=clear,local,pka,dane,cert,keyserver",
+                               "--keyserver=pool.sks-keyservers.net",
+                               "--quiet",
+                               "--batch",
+                               "--output",
+                               f.name,
+                               "-"], env={"LANG": 'en_US.UTF-8'}, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE) as p:
+            #if not bdata.find('\r\n') >= 0:
+            #    bdata = bdata.replace('\n', '\r\n')  # Windows hack
+            p.stdin.write(bdata.encode() if isinstance(bdata, str) else bdata)
+            p.stdin.close()
+
+            gpg_status = [l for l in gpg_status_parser.parse(p.stdout)]
+            p.wait()
+            gpg_output = p.stderr.read()
+            gpg_rcode = p.returncode
+
+    except Exception as e:
+        yield MailTest("An error occured: %s" % e, 1)
+        return
+
+    if os.path.exists(f.name):
+        with open(f.name, 'rb') as fp:
+            bdata = fp.read()
+        os.unlink(f.name)
+    else:
+        bdata = None
+
+    yield from verify_sign(bdata, gpg_rcode, gpg_status, gpg_output.decode('utf-8'))
diff --git a/test.py b/test.py
new file mode 100644
index 0000000..a844484
--- /dev/null
+++ b/test.py
@@ -0,0 +1,26 @@
+class MailTest:
+
+    def __init__(self, title, value=0, details=None):
+        self._title = title
+        self._value = value
+        self._details = details
+
+    @property
+    def title(self):
+        return self._title
+
+    @property
+    def value(self):
+        return self._value
+
+    @property
+    def valuestr(self):
+        if self._value < -1:    return "       "
+        elif self._value < 0:  return "[    ] "
+        elif self._value == 0: return "[ OK ] "
+        elif self._value == 2: return "[WARN] "
+        elif self._value == 1: return "[FAIL] "
+
+    @property
+    def details(self):
+        return self._details