TY - JOUR
AU - Osmanbey Uzunkol
AB - Ren and Jiang recently published a “verifiable outsourced attribute-based signature scheme” in Multimedia Tools and Applications. In this note, we first provide two attacks on the verifiability of the semi-signatures of this scheme by showing that a malicious signing-cloud service provider (S-CSP) can always cheat the signer unlike the authors’ claim. Moreover, one of these attacks also implies that an untrusted S-CSP can always forge signatures contrary to the claimed unforgeability against chosen message attacks. Therefore, this scheme unfortunately does not satisfy the main security properties for a delegated signature scheme.
BT - Multimedia Tools and Applications 
DA - 2019/05/01
DO - 10.1007/s11042-018-6725-7
IS - 9
N2 - Ren and Jiang recently published a “verifiable outsourced attribute-based signature scheme” in Multimedia Tools and Applications. In this note, we first provide two attacks on the verifiability of the semi-signatures of this scheme by showing that a malicious signing-cloud service provider (S-CSP) can always cheat the signer unlike the authors’ claim. Moreover, one of these attacks also implies that an untrusted S-CSP can always forge signatures contrary to the claimed unforgeability against chosen message attacks. Therefore, this scheme unfortunately does not satisfy the main security properties for a delegated signature scheme.
PY - 2019
SN - 1573-7721
SP - 11735
EP - 11742
EP - 
T2 - Multimedia Tools and Applications 
TI - Comments on “verifiable outsourced attribute-based signature scheme”
UR - https://doi.org/10.1007/s11042-018-6725-7
VL - 78
ER -