Hi Werner,
during implementation of V5 keys and signatures in LibTMCG I discovered
a minor issue with RFC 4880bis. Section 5.2.4 says at third paragraph:
"When a signature is made over a key, the hash data starts with the
octet 0x99, followed by a two-octet length of the key, and then body
of the key packet."
There is no distinction between V3, V4, and V5 signatures resp. keys.
However, GnuPG computes the hash in function hash_public_key() for V5
keys in a different way: starting with octet 0x9a and a four-octet
length is given before the body of key packet is hashed.
Thus, either this part should be specified in RFC 4880bis with more
detail or GnuPG has to change its hash computation for signatures.
Best regards,
Heiko.
PS. Taking the above issue into account the given V5 sample key is
recognized by LibTMCG as required:
PrivateKeyBlockParse(emma_armored, 3, "", emma)
INFO: PacketDecode() = 5 version = 5
INFO: encdatalen = 0
INFO: skalgo = 0
INFO: aeadalgo = 0
INFO: s2kconv = 0
INFO: s2k_type = 0 s2k_hashalgo = 0 s2k_count = 0
INFO: key ID of private primary key: 19 34 7b c9 87 24 64 2
INFO: PacketDecode() = 13 version = 0
INFO: signature subpacket type = 33 found
INFO: signature subpacket type = 2 found
INFO: signature subpacket type = 27 found
INFO: signature subpacket type = 11 found
INFO: signature subpacket type = 34 found
INFO: signature subpacket type = 21 found
INFO: signature subpacket type = 22 found
INFO: signature subpacket type = 30 found
INFO: signature subpacket type = 23 found
INFO: PacketDecode() = 2 version = 5
INFO: EdDSA rbits = 254 sbits = 255
INFO: PacketDecode() = 7 version = 5
INFO: encdatalen = 0
INFO: skalgo = 0
INFO: aeadalgo = 0
INFO: s2kconv = 0
INFO: s2k_type = 0 s2k_hashalgo = 0 s2k_count = 0
INFO: key ID of private subkey: e4 55 7c 2b 2 ff bf 4b
INFO: signature subpacket type = 33 found
INFO: signature subpacket type = 2 found
INFO: signature subpacket type = 27 found
INFO: PacketDecode() = 2 version = 5
INFO: EdDSA rbits = 256 sbits = 256
CheckSelfSignatures()
INFO: key ID of primary key: 19 34 7b c9 87 24 64 2
INFO: fingerprint of primary key: 19 34 7b c9 87 24 64 2 5f 99 df 3e c2
e0 0 e d9 88 48 92 e1 f7 b3 ea 4c 94 0 91 59 56 9b 54
INFO: number of selfsigs = 0
INFO: number of keyrevsigs = 0
INFO: number of certrevsigs = 0
INFO: number of userids = 1
INFO: number of userattributes = 0
INFO: number of subkeys = 1
INFO: number of revkeys = 0
INFO: userid = "emma(_dot_)goldman(_at_)example(_dot_)net"
INFO: number of selfsigs = 1
INFO: number of revsigs = 0
INFO: number of certsigs = 0
INFO: sig type = 0x13 pkalgo = 22 hashalgo = 8 revocable = true
exportable = true version = 5 creationtime = 1553069284 expirationtime =
0 keyexpirationtime = 0 revcode = 0 packet.size() = 152 hspd.size() = 72
issuer = 19 34 7b c9 87 24 64 2 issuerfpr = 19 34 7b c9 87 24 64 2 5f
99 df 3e c2 e0 0 e d9 88 48 92 e1 f7 b3 ea 4c 94 0 91 59 56 9b 54
keyflags = 3 revkeys.size() = 0
INFO: left = f5 c0
INFO: user ID is valid
INFO: primary key update expirationtime to 0
INFO: primary key update flags to 3
INFO: primary key update features to 7
INFO: primary key update psa to 9 8 7 2
INFO: primary key update pha to 10 9 8 11 2
INFO: primary key update pca to 2 3 1
INFO: primary key update paa to 2 1
INFO: primary key update revkeys with added
INFO: key flags on primary key are CS
CheckSubkeys()
INFO: key ID of subkey: e4 55 7c 2b 2 ff bf 4b
INFO: fingerprint of subkey: e4 55 7c 2b 2 ff bf 4b 4 f8 74 1 ec 33 6a
f7 13 3d f 85 be 7f d0 9b ae fd 9c ae b8 c9 39 65
INFO: number of selfsigs = 0
INFO: number of bindsigs = 1
INFO: number of pbindsigs = 0
INFO: number of keyrevsigs = 0
INFO: number of certrevsigs = 0
INFO: number of revkeys = 0
INFO: sig type = 0x18 pkalgo = 22 hashalgo = 8 revocable = true
exportable = true version = 5 creationtime = 1553069284 expirationtime =
0 keyexpirationtime = 0 revcode = 0 packet.size() = 124 hspd.size() = 44
issuer = 19 34 7b c9 87 24 64 2 issuerfpr = 19 34 7b c9 87 24 64 2 5f
99 df 3e c2 e0 0 e d9 88 48 92 e1 f7 b3 ea 4c 94 0 91 59 56 9b 54
keyflags = c revkeys.size() = 0
INFO: left = 39 24
INFO: subkey update expirationtime to 0
INFO: subkey update flags to c
INFO: subkey update features to
INFO: subkey update psa to
INFO: subkey update pha to
INFO: subkey update pca to
INFO: subkey update paa to
INFO: subkey update revkeys with added
INFO: subkey is valid
INFO: key flags on subkey are Ee
!primary->Weak()
INFO: EdDSA with curve "Ed25519" and 256 bits
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