For me the text and examples are not clear. „sha1-hash-of-image“ in the example doesn’t say anything about the encoding.
And „not the base64-encoded version“ reads as: Don’t do byte[] hash = sha1(base64(image_bytes)); but instead do byte[] hash = sha1(image_bytes); It still doesn’t say anything about how to encode the byte array hash in XML. Seems like base64 encoding is not used. Jonas, I have no objections to clarify the usage of lower-case hex encoding. —Christian > Am 25.02.2018 um 20:45 schrieb Tedd Sterr <[email protected]>: > > Igonre the schema - it doesn't appear to be complete or correct. The text & > examples make it clear: > > > "the user's client computes the SHA1 hash of the avatar image data itself > (not the base64-encoded version) in accordance with RFC 3174 [4]." > > <presence from='[email protected]/balcony'> > <x xmlns='vcard-temp:x:update'> > <photo>sha1-hash-of-image</photo> > </x> > </presence> > > > The hash value is the hexadecimal representation of the SHA1 digest (40 > characters, representing 20 bytes.) > ('not the base64-encoded version' means the hash is calculated from the raw > image data, not the base64 version that will be sent.) > > The image data is the base64 encoded binary content of the image file. > > "The <PHOTO/> element SHOULD contain a <BINVAL/> child whose XML character > data is Base64-encoded data for the avatar image." > > > I've never seen any examples to the contrary; and I suspect no receiving > clients would support any such deviations. > > > > From: Standards <[email protected]> on behalf of Christian Schudt > <[email protected]> > Sent: 24 February 2018 19:22 > To: XMPP Standards > Subject: [Standards] XEP-0153: Encoding of photo hash? > > Hi list, > > I’ve got a question about XEP-0153. Its XML schema defines that the photo > hash is encoded as Base64: > > <xs:element name='photo' minOccurs='0' type='xs:base64Binary‘/> > > However, I’ve seen the hash encoded as hexadecimal, too. It was no small > client, but it was Facebook. > I don’t know how other clients behave. > > So I wonder, what is the correct encoding of the photo hash value: base64 or > hex-encoded? > > Kind regards, > — Christian > _______________________________________________ > Standards mailing list > Info: https://mail.jabber.org/mailman/listinfo/standards > Unsubscribe: [email protected] > _______________________________________________ _______________________________________________ Standards mailing list Info: https://mail.jabber.org/mailman/listinfo/standards Unsubscribe: [email protected] _______________________________________________
