{'fraction_non_alphanumeric': 0.0274949083503055, 'fraction_numerical': 0.0, 'mean_word_length': 5.42483660130719, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A New Identity Based Signcryption Scheme in the Standard Model

Signcryption is a useful cryptographic primitive which simultaneously performs encryption and signature with cost less than the signature-then-encryption approach. Identity-based signcryption (IBSC) eliminates the complicated management of certificates in signcryption schemes in the traditional public-key infrastructure (PKI) setting. Most IBSC schemes are constructed in the random oracle model, while it is unknown how to instantiate a really "random" oracle in the real world. By exploiting Boneh et al.'s strongly unforgeable signature and Paterson et al.'s identity-based signature, this paper proposes a new IBSC scheme in the standard model. It is proven that our IBSC scheme satisfies semantic security and strong unforgeability under the bilinear decision Diffie-Hellman (BDDH) assumption. The proofs do not rely on random oracles. Performance analysis shows that our scheme is also efficient and practical.