A signmii attests that a document, a photo, an archive or any digital file existed at a certified time.
Technically, a signmii is the result of the ciphering with an RSA key of a SHA1 digest, a GMT timestamp and a serial number. A signmii is always built by signmii.com. The contents of a signmii can be checked and displayed by signmii.com but also independently with free public programs.
The timestamp registered in a signmii is always the GMT time of its creation. The SHA1 associated to the timestamp proves that the corresponding file hasn't been modified since the signmii which contains its digital digest was created. The encoding with the private part of an RSA key ensures that only signmii.com can encrypt a signmii while allowing anyone to decrypt a signmii with the public part of the key. IMPORTANT: The certified file is never transmitted to signmii.com. The SHA1 is enough. The confidentiality of the data is guarantied.
signmii.com can code a signmii in a QR. Scanning the QR displays the content of the signmii.