On Dec 14, 2007, at 8:40 AM, Hector Santos wrote:
DKIM-BASE Verify Results:
NONE - No signature in mail
PASS - Good Signature, Original Address Signer
PASS 3P3 - Good Signature, 3rd party Signer
FAIL - Bad Signature, Original Address Signer
FAIL 3P3 - Bad Signature, 3rd party Signer
Hector,
This breakdown provides only limited value for assessing benefits, and
nothing in terms of creating a specification. A specification should
not attempt to dictate message disposition weighting. Nevertheless,
this breakdown should be adjusted to recognize that an invalid
signature is equivalent to no signature per the specification. The
"on-behalf-of" should not matter as well. Verifiers should retain
domain histories to assign a domain weight. Domain weights might
range from -4 to +4, for example. So this provides:
NONE - No or invalid signature
VSOBHOF - Valid Signature "on-behalf-of" From
VSOBHOO - Valid Signature "on-behalf-of" Other than From (g=*)
TPS - Valid third-party signature
+----------------------------+
| Policy Assertions |
+---------+----------------------------+
| STATE | UNKNOWN | ALL | STRICT |
+======================================+
| NONE | NC | AIS | SIS |
|---------+---------+--------+---------+
| VSOBHOF | DR | DR | DR |
|---------+---------+--------+---------+
| VSOBHOO | DR | DR | DR |
|---------+---------+--------+---------+
| TPS | TPDR | ATPDR | STPDR |
|---------+---------+--------+---------+
Category Disposition
NC - no change
DR - relative to signing domain
TPDR - relative to third-party signing domain
AIS - "all" with invalid signature
SIS - "strict" with invalid signature
ATPDR - relative to "all" with third-party signature
STPDR - relative to "strict" with third-party signature
Disposition Weights
NC - 0
DR - (OF or OO) domain +2
TPDR - third-party domain +1
AIS - -2
SIS - -3
ATPDR - third-party domain
STPDR - third-party domain -1
Dropping "strict" and just using first-party domains regardless of
which header the signature was "on-behalf-of" provides:
FDS - From domain signature
+-------------------+
| Policy Assertions |
+---------+-------------------+
| STATE | UNKNOWN | ALL |
+=============================+
| NONE | NC | AIS |
|---------+---------+---------+
| FDS | DR | DR |
|---------+---------+---------+
| TPS | TPDR | ATPDR |
|---------+---------+---------+
Category Disposition
NC - no change
DR - relative to signing domain
TPDR - relative to third-party signing domain
AIS - "all" with invalid signature
ATPDR - relative to "all" with third-party signature
Disposition Weights
NC - 0
DR - domain +2
TPDR - third-party domain +1
AIS - -1
ATPDR - third-party domain
-Doug
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