Random pixel selection is one of the image steganography methods that has achieved significant success in enhancing the robustness of hidden data.This property makes it difficult for steganalysts’powerful data extrac...Random pixel selection is one of the image steganography methods that has achieved significant success in enhancing the robustness of hidden data.This property makes it difficult for steganalysts’powerful data extraction tools to detect the hidden data and ensures high-quality stego image generation.However,using a seed key to generate non-repeated sequential numbers takes a long time because it requires specific mathematical equations.In addition,these numbers may cluster in certain ranges.The hidden data in these clustered pixels will reduce the image quality,which steganalysis tools can detect.Therefore,this paper proposes a data structure that safeguards the steganographic model data and maintains the quality of the stego image.This paper employs the AdelsonVelsky and Landis(AVL)tree data structure algorithm to implement the randomization pixel selection technique for data concealment.The AVL tree algorithm provides several advantages for image steganography.Firstly,it ensures balanced tree structures,which leads to efficient data retrieval and insertion operations.Secondly,the self-balancing nature of AVL trees minimizes clustering by maintaining an even distribution of pixels,thereby preserving the stego image quality.The data structure employs the pixel indicator technique for Red,Green,and Blue(RGB)channel extraction.The green channel serves as the foundation for building a balanced binary tree.First,the sender identifies the colored cover image and secret data.The sender will use the two least significant bits(2-LSB)of RGB channels to conceal the data’s size and associated information.The next step is to create a balanced binary tree based on the green channel.Utilizing the channel pixel indicator on the LSB of the green channel,we can conceal bits in the 2-LSB of the red or blue channel.The first four levels of the data structure tree will mask the data size,while subsequent levels will conceal the remaining digits of secret data.After embedding the bits in the binary tree level by level,the model restores the AVL tree to create the stego image.Ultimately,the receiver receives this stego image through the public channel,enabling secret data recovery without stego or crypto keys.This method ensures that the stego image appears unsuspicious to potential attackers.Without an extraction algorithm,a third party cannot extract the original secret information from an intercepted stego image.Experimental results showed high levels of imperceptibility and security.展开更多
The concurrent manipulation of an expanded AVL tree (EAVL tree) is considered in this paper. The presented system can support any number of concurrent processes which perform searching, insertion and deletion on the t...The concurrent manipulation of an expanded AVL tree (EAVL tree) is considered in this paper. The presented system can support any number of concurrent processes which perform searching, insertion and deletion on the tree. Simulation results indicate the high performance of the system. Elaborate techniques are used to achieve such a system unawilable based on any known algorithms. Methods developed in this paper may provide new insights into other problems in the area of concurrent search structure manipulation.展开更多
针对传统AVL(Adelson-Velskii and Landis)树重平衡算法代码量大、流程复杂、调整率过高的问题,提出一种统一重平衡算法,并提出广义AVL树的概念。统一重平衡算法能对AVL树的失衡节点进行自动分类、调整,取消了传统重平衡方法中的四种旋...针对传统AVL(Adelson-Velskii and Landis)树重平衡算法代码量大、流程复杂、调整率过高的问题,提出一种统一重平衡算法,并提出广义AVL树的概念。统一重平衡算法能对AVL树的失衡节点进行自动分类、调整,取消了传统重平衡方法中的四种旋转操作。广义AVL树放松了AVL树的平衡约束,允许左右子树树高相差不超过N(N≥1),当更新操作(插入/删除)执行后,广义AVL树只在平衡约束条件不满足时采用统一重平衡算法进行调整。理论分析与实验结果表明,广义AVL树的调整率随着N的增大而显著降低:N为5时,调整率低于4%;N为13时调整率低于千分之一。广义AVL树的调整率远低于红黑树等经典数据结构,适合并发应用。展开更多
针对现有保序加密(order-preserving encryption,OPE)方案中客户端与服务端多轮交互导致的较大通信开销问题,提出一种基于本地临时缓存表和自平衡二叉搜索树的保序加密方案。在数据插入阶段通过客户端临时缓存表对插入数据预处理确定初...针对现有保序加密(order-preserving encryption,OPE)方案中客户端与服务端多轮交互导致的较大通信开销问题,提出一种基于本地临时缓存表和自平衡二叉搜索树的保序加密方案。在数据插入阶段通过客户端临时缓存表对插入数据预处理确定初始交互节点,避免从根节点开始交互,降低算法的通信开销;并使用平衡因子为k的AVL(Adelson-Velsky and Landis)树作为编码树,避免频繁的编码更新带来的较大计算开销。此外,采用格式保留加密算法FF1-SM4对数据进行加密,不仅能够提高存储效率,而且无需对数据库表结构进行大幅修改,也无需对应用程序进行修改以适应密文的变化。实验结果表明,当插入5000条数据时,该方案相较gmOPE加密效率提升约13.91%,单次插入的平均交互次数下降约69.81%。展开更多
文摘Random pixel selection is one of the image steganography methods that has achieved significant success in enhancing the robustness of hidden data.This property makes it difficult for steganalysts’powerful data extraction tools to detect the hidden data and ensures high-quality stego image generation.However,using a seed key to generate non-repeated sequential numbers takes a long time because it requires specific mathematical equations.In addition,these numbers may cluster in certain ranges.The hidden data in these clustered pixels will reduce the image quality,which steganalysis tools can detect.Therefore,this paper proposes a data structure that safeguards the steganographic model data and maintains the quality of the stego image.This paper employs the AdelsonVelsky and Landis(AVL)tree data structure algorithm to implement the randomization pixel selection technique for data concealment.The AVL tree algorithm provides several advantages for image steganography.Firstly,it ensures balanced tree structures,which leads to efficient data retrieval and insertion operations.Secondly,the self-balancing nature of AVL trees minimizes clustering by maintaining an even distribution of pixels,thereby preserving the stego image quality.The data structure employs the pixel indicator technique for Red,Green,and Blue(RGB)channel extraction.The green channel serves as the foundation for building a balanced binary tree.First,the sender identifies the colored cover image and secret data.The sender will use the two least significant bits(2-LSB)of RGB channels to conceal the data’s size and associated information.The next step is to create a balanced binary tree based on the green channel.Utilizing the channel pixel indicator on the LSB of the green channel,we can conceal bits in the 2-LSB of the red or blue channel.The first four levels of the data structure tree will mask the data size,while subsequent levels will conceal the remaining digits of secret data.After embedding the bits in the binary tree level by level,the model restores the AVL tree to create the stego image.Ultimately,the receiver receives this stego image through the public channel,enabling secret data recovery without stego or crypto keys.This method ensures that the stego image appears unsuspicious to potential attackers.Without an extraction algorithm,a third party cannot extract the original secret information from an intercepted stego image.Experimental results showed high levels of imperceptibility and security.
文摘The concurrent manipulation of an expanded AVL tree (EAVL tree) is considered in this paper. The presented system can support any number of concurrent processes which perform searching, insertion and deletion on the tree. Simulation results indicate the high performance of the system. Elaborate techniques are used to achieve such a system unawilable based on any known algorithms. Methods developed in this paper may provide new insights into other problems in the area of concurrent search structure manipulation.
文摘针对传统AVL(Adelson-Velskii and Landis)树重平衡算法代码量大、流程复杂、调整率过高的问题,提出一种统一重平衡算法,并提出广义AVL树的概念。统一重平衡算法能对AVL树的失衡节点进行自动分类、调整,取消了传统重平衡方法中的四种旋转操作。广义AVL树放松了AVL树的平衡约束,允许左右子树树高相差不超过N(N≥1),当更新操作(插入/删除)执行后,广义AVL树只在平衡约束条件不满足时采用统一重平衡算法进行调整。理论分析与实验结果表明,广义AVL树的调整率随着N的增大而显著降低:N为5时,调整率低于4%;N为13时调整率低于千分之一。广义AVL树的调整率远低于红黑树等经典数据结构,适合并发应用。
文摘针对现有保序加密(order-preserving encryption,OPE)方案中客户端与服务端多轮交互导致的较大通信开销问题,提出一种基于本地临时缓存表和自平衡二叉搜索树的保序加密方案。在数据插入阶段通过客户端临时缓存表对插入数据预处理确定初始交互节点,避免从根节点开始交互,降低算法的通信开销;并使用平衡因子为k的AVL(Adelson-Velsky and Landis)树作为编码树,避免频繁的编码更新带来的较大计算开销。此外,采用格式保留加密算法FF1-SM4对数据进行加密,不仅能够提高存储效率,而且无需对数据库表结构进行大幅修改,也无需对应用程序进行修改以适应密文的变化。实验结果表明,当插入5000条数据时,该方案相较gmOPE加密效率提升约13.91%,单次插入的平均交互次数下降约69.81%。
