This paper extends the concept of the specific verification function (SVF), introduced by Cui et al. in formally describing the Naor transformation, from hierarchical identity-based encryption (HIBE) to hierarchical identity-based cryptog-raphy (HIBC), including hierarchical identity-based signature (HIBS), where the Naor transformation can convert a secure (H)IBE scheme to a secure (H)IBS one. We formulate this extended concept, checkable key generation (CKG), give its syntax, and classify it into two types: fully and partially ones. We also define security notions of CKG, named unextractability (UE) against several attacks. Next, we show that an$\boldsymbol{\ell}$-level CKG component can be constructed from an$\boldsymbol{\ell}$-level HIBS scheme, and an$\boldsymbol{\ell}$-level HIBS scheme can be constructed from an$(\ell+1)$-level CKG component. Both give security enhancement of HIBS from a weakly secure scheme to a strongly secure one. In addition, we mention that an HIBS scheme with constant-size signatures can be constructed from a partially CKG component.

This paper examines a security enhancement technique from a passively secure hierarchical identity-based identification (HIBI) protocol to a concurrently secure one. Two types of security enhancement techniques for the identification protocols have been proposed: one based on the OR-proof technique and the other using a chameleon hash function. The former has been examined in detail, while the latter has not been formulated in the HIBI protocol, and its close evaluation of applicability, especially in identity-selecting settings, and reduction efficiency has not been made public. We describe a transformation using a chameleon hash function and compare it with the others based on the OR-proof technique in applicability and reduction efficiency.

We have proposed the MAP (Multi-Angled Parallel) operation method which extracts geometric features from a topographic map using erosion-dilation operations on a directional feature field. We have also proposed the MAP matching method which recognizes fixed-shaped symbols in the topographic map by using parallel operations on the same directional feature field. We have shown that all kinds of feature extraction and recognition can be effectively performed within the framework of parallel operation. In this paper, we show that elevation values in a topographic map can be recognized by a combination of MAP operation with the MAP matching. Numerals and symbols are recognized by the MAP matching method, while small dots and lines are extracted by the MAP operation method. These results are used together to determine the value, position and attribute of elevations in topographic maps.

As a recognition method of characters stamped on the metal, a process without binarization is proposed. Segmentation and recognition are performed simultaneously by exhaustive pattern matching at every location using multi-angled parallel matching method, where multiple directional planes and graylevel feature are combined as an input feature. The effectiveness is proved by experiments for laser-marked alphanumerics.>