Inter national J our nal of Inf ormatics and Communication T echnology (IJ-ICT) V ol. 15, No. 3, September 2026, pp. 1238 1253 ISSN: 2252-8776, DOI: 10.11591/ijict.v15i3.pp1238-1253 1238 Classication of encryption attacks and strategies f or mitigation Anas Maaif , Khalid Zine-Dine Department of Computer Science, F aculty of Sciences, Mohammed V Uni v ersity , Rabat, Morocco Article Inf o Article history: Recei v ed Apr 28, 2025 Re vised Mar 17, 2026 Accepted May 21, 2026 K eyw ords: Classication of attacks Cryptograph y Cybersecurity Defense strate gies Mitig ation ABSTRA CT Cryptograph y is essential for securing digital communications, yet it remains vulnerable to v arious malicious attacks. These attacks can be classied based on the type of cryptograph y the y tar get symmetric or asymmetric. This pa- per presents a comprehensi v e classication of encryption attacks, e xamining the specic vulnerabilities associated with each cryptographic approach. By ana- lyzing these attack v ectors, the study sho ws the importance of understanding weaknesses in cryptographic systems. Furthermore, it proposes se v eral mitig a- tion strate gies to strengthen defenses and enhance protection of sensiti v e infor - mation in the digital domain. This is an open access article under the CC BY -SA license . Corresponding A uthor: Anas Maai Department of Computer Science, F aculty of Sciences, Mohammed V Uni v ersity Rabat, Morocco Email: anas maai@um5.ac.ma 1. INTR ODUCTION In today’ s digital landscape, where v ast amounts of information are e xchanged continuously , cryp- tograph y serv es as the cornerstone of security , ensuring the condentiality , inte grity and authenticity of digital communications. Ho we v er , crypt ographic systems, while vital, are not immune to the e v er -e v olving threats posed by malicious actors. This paper e xplores the critical area of cryptographic security , emphasizing its foundational role in protecting digital interactions. The study aims to pro vide a nuanced understanding of the v arious attacks that tar get cryptographic protocols, classifying them to better underst and the threat landscape and f acilitate the de v elopment of tailored defense strate gies. Central to this classication is the distinction between symmetric and asymmetric cryptog- raph y , each presenting unique vulnerabilities that attack ers can e xploit. The most common attack ag ainst symmetric cryptograph y is brut e-force, while man-i n-the-middle attacks are pre v alent in asymmetric cryptograph y . Usually , attack ers primarily focus on breaking or bypassing cryptographic k e ys, whereas defenders emphasize k e y length, algorithmic resilience and additional layers of protection tai lored to specic attacks. Existing research, ho we v er , often addresses either attack descriptions or mitig ation strate gies in isolation, with fe w studies pro viding a structured classication that links each attack to its practical limitations and countermeasures. This approach limits comprehensi v e understanding, making it dif cult for researchers to systematically assess security or design inte grated defense strate gies. A unied frame w ork that cate gorizes attacks, aligns them with cryptographic paradigms, and highlights mitig ation mech- anisms remains lar gely absent in the literature. By e xamining attacks ag ainst both types of cryptographic schemes, this w ork seeks to unra v el the specic challenges inherent in each paradi g m . Through a comprehensi v e classication, the paper highlights the J ournal homepage: http://ijict.iaescor e .com Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Inf & Commun T echnol ISSN: 2252-8776 1239 di v erse attack v ectors that threaten cryptographic securi ty , pa ving the w ay for the strate gies of rob ust security measures. This paper is or g anized as follo ws: Section 2 pro vides a background on symmetric and asymm etric cryptograph y , laying the foundation for S ection 3, where we classify the v arious attacks on each cryptographic type. In addition to understanding cryptographic attack methodologies, it is equally important to study the mechanisms used to defend ag ainst them. Ef fecti v e defense strate gies play a critical role in preserving data condentiality , inte grity and authenticity . As attack techniques continue to e v olv e, cryptographic systems must adopt adapti v e and layered security measures. In this paper , section 4 therefore emphasizes defensi v e approaches and strate gies as a fundamental component of secure cryptographic design, enhancing the resilience of cryptographic systems and ensuring better protection of sensiti v e information. T o address these challenges, this paper pro vides a s tructured analysis of cryptographic attacks and defenses. Specically , it pro vides a taxonomy of attacks on symmetric and asymmetric cryptograph y , maps each attack to its associated vulnerabilities, risks, and practical implications, proposes mitig ation strate gies tailored to specic attack types, and highlights emer ging directions, including AI and ML dri v en approaches to enhancing cryptographic security . 2. CR YPT OGRAPHY O VER VIEW In this section, we focus on tw o primary types of symmetric and asymmetric cryptogra ph y , each of which plays a critical role in safe guarding information. W e will e xamine their core objecti v es, functionality , and areas of application, shedding light on ho w the y contrib ute to modern security practices. 2.1. Symmetric cryptograph y Symmetric cryptograph y , also kno wn as secret-k e y cryptograph y , in v olv es the use of a single k e y for both encryption and decryption processes. It is characterized by its ef cienc y in encrypting lar ge amounts of data due to the relati v ely simple and f ast algorithm s emplo yed. Common e xamples of symmetric encryption algorithms include the adv anced encryption standard (AES) and the data encryption standard (DES) (see [1]- [6]). The Figure 1 sho ws a comprehensi v e structure of symmetric cryptograph y . Objecti v es of symmetric cryptograph y: Condentiality: ensuring that inform ation is only accessible to authorized parties who possess the secret k e y . Inte grity: protecting data from unauthorized alterations. Authentication: v erifying that the sender and recei v er of the message are le gitimate. Ef cienc y: enabling f ast and resource-ef fecti v e encryption and decryption of data. Use cases: Data encryption: symmetric encryption is widely used for b ulk data encryption, such as securing les, databases, and communication streams in real-time systems. Secure communication: symmetric k e ys are often emplo yed in securing communication channels, such as in virtual pri v ate netw orks (VPNs) and secure sock ets layer (SSL)/transport layer security (TLS) protocols. Disk and le encryption: full disk encryption tools lik e BitLock er and le encryption softw are lik e V er - aCrypt rely on symmetric encryption to safe guard stored data. Figure 1. Symmetric cryptograph y protocol Classication of encryption attac ks and str ate gies for mitigation (Anas Maai) Evaluation Warning : The document was created with Spire.PDF for Python.
1240 ISSN: 2252-8776 Despite its adv antages, symmetric cryptograph y presents challenges, particularly in the secure e x- change of k e ys between parties. This vulnerability is addressed by asymmetric cryptograph y , which we e xplore in the follo wing section. 2.2. Asymmetric cryptograph y Asymmetric cryptograph y , also referred to as public-k e y cryptograph y , uses tw o distinct k e ys: a public k e y for encryption and a pri v ate k e y for decryption. The tw o k e ys are mathematically related, b ut it is com- putationally infeasible to deri v e the pri v ate k e y from the public k e y . Popular asymmetric algorithms include the Ri v est-Shamir -Adleman (RSA), Dif e-Hellman, and elliptic curv e cryptograph y (ECC) (see [7]-[11]). The Figure 2 sho ws a comprehensi v e structure of asymmetric cryptograph y . Objecti v es of asymmetric cryptograph y: Condentiality: protecting data by ensuring that only the holder of the pri v ate k e y can decrypt the informa- tion. Authentication: v erifying the identity of the parties in v olv ed in the communication through digital signa- tures. Non-repudiation: ensuring that the sender cannot den y ha ving sent the message, enabled by digital signature v erication. K e y e xchange: enabling secure k e y distrib ution o v er insecure channels without the need for a shared secret. Use cases: Digital signatures: asymmetric cryptograph y underpins digital signature schemes used for authenticating the sender’ s identity and ensuring message inte grity . K e y e xchange protocols: protocols lik e SSL/TLS use asymmetric encryption to securel y e xchange symmet- ric k e ys, which are then used for f aster data encryption during communication. Email encryption: pretty good pri v ac y (PGP) and secure/multipurpose internet mail e xtensions (S/MIME) rely on asymmetric cryptograph y to secure email communications. Certicate authorities: public-k e y infrastructure (PKI) systems use asymmetric cryptograph y to issue digital certicates, enabling trust in secure communications. While asymmetric cryptograph y o v ercomes the k e y distrib ution problem, it is computationally more intensi v e than symmetric cryptograph y , making it less ef cient for encrypting lar ge v olumes of data. Both sym- metric and asymmet ric cryptographic systems serv e critical roles in modern c ybersecurity , with each of fering unique strengths and addressing specic challenges. Symmetric cryptograph y e xcels in ef cienc y , making it ideal for encrypting lar ge datasets, while asymmetric cryptograph y pro vides enhanced security features, par - ticularly in k e y management and authentication. By understanding the objecti v es and applications of these tw o cryptographic types, we can better appreciate the multif aceted nature of cryptographic security and the importance of emplo ying them in tandem to b uild rob ust, secure systems. Figure 2. Asymmetric cryptograph y protocol 3. A TT A CKS A GAINST CR YPT OGRAPHIC PR O T OCOLS Cryptographic protocols are fundamental to the security of modern digital systems, pro viding mecha- nisms for secure communication, data inte grity , and authentication. Ho we v er , these protocols are not in vulner - able and ha v e been the tar get of v arious attacks designed to e xploit weaknesses in their underlying algorithms, implementation, or k e y management systems. The classication of these attacks can be broadly di vi ded based on the type of cryptograph y used symmetric or asymmetric each of which is subject to distinct attack v ec- Int J Inf & Commun T echnol, V ol. 15, No. 3, September 2026: 1238–1253 Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Inf & Commun T echnol ISSN: 2252-8776 1241 tors. Understanding these attack cate gories is essential for identifying vulnerabil ities and de v e loping more resilient cryptographic systems. In this section, we pro vide a comprehensi v e classication of attacks ag ainst both symmetric and asymmetric cryptographic protocols (see [12]-[19]). 3.1. Attacks against symetric cryptograph y pr otocols 3.1.1. Brute f or ce attacks A brute force attack is a method used by attack ers to g ain unauthorized access to a system by syst em- atically attempting all possible combinations of k e ys or passw ords until the correct one is found. This attack e xploits the computational po wer a v ailable to test e v ery potential k e y or passw ord in a gi v en k e y space, which is the total number of possible k e ys that can be generated based on the length and comple xity of the passw ord or encryption k e y . Process: Figure 3 sho ws t he process of a Bruteforce attack. The ef fecti v eness of brute force atta cks diminishes as k e y lengths increase, b ut the y remain a persistent threat when passw ords or encryption k e ys are inadequately comple x. Figure 3. Bruteforce attack’ s process Example of brute force attack: an attack er attempts to break a DES-encrypted message by systemati - cally trying all 2 56 possible k e ys until the correct k e y is found. Due to the relati v ely short k e y length of DES, such attacks ha v e become feasible with modern computing po wer , rendering DES insecure ag ainst brute-force attacks. 3.1.2. Fr equency analysis attacks Frequenc y analysis attack is a cryptanalytic technique used to decipher information by e xploiting the frequenc y of symbols in a cipherte xt. This method is particularly ef fecti v e ag ainst simple substitution ciphers, where each letter or symbol in the plainte xt i s consistently replaced by a corresponding symbol in the cipherte xt. By analyzing the frequenc y of symbols in the cipherte xt, attack ers can deduce correspondences between the cipherte xt symbols and the common letters in the plainte xt, thereby breaking the cipher . Process: Figure 4 sho ws the process of a frequenc y analysis attack. This type of attack is particul arly ef fecti v e ag ainst clas sical ciphers lik e the Caesar cipher and other si mple substitution ciphers, where symbol frequencies in the cipherte xt closely reect those in the plainte xt. Example of frequenc y analysis attack: in a monoalphabetic substitution cipher , the attack er observ es that the most frequent symbol in the cipherte xt appears approxi mately 13% of the time. By correlating this frequenc y with t he letter “E, which is the most common letter in English, the attack er can be gin reconstructing the plainte xt and e v entually reco v er the full message. Classication of encryption attac ks and str ate gies for mitigation (Anas Maai) Evaluation Warning : The document was created with Spire.PDF for Python.
1242 ISSN: 2252-8776 Figure 4. Frequenc y analysis attack process 3.1.3. Exhausti v e sear ch attacks Exhausti v e search attacks, one of the brute-force attacks, in v olv e systematically attempting all pos sible combinations of characters to nd a secret, such as a passw ord or encryption k e y . This attack method is commonly used in scenarios lik e passw ord and encryption k e y cracking, where e v ery concei v able combination is tested until the correct one is identied. The ef fecti v eness of an e xhausti v e search attack depends on the size of the solution space, which is the total number of possible combinations. Lar ger solution spaces mak e the attack more time-consuming and computationally e xpensi v e, as the number of combinations to be tested increases e xponentially . Process: the Figure 5 sho ws the process of an e xhausti v e search attack. Example of e xhausti v e search attack: an attack er tar gets an AES-128 encrypted le and attempts e v ery possible k e y in the 2 128 k e y space. Although theoretically pos sible, the enormous size of the k e y space mak es such an attack computationally infeasible, demonstrating ho w increased k e y length mitig ates e xhausti v e search attacks. Figure 5. Exhausti v e search attack’ s process Int J Inf & Commun T echnol, V ol. 15, No. 3, September 2026: 1238–1253 Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Inf & Commun T echnol ISSN: 2252-8776 1243 3.1.4. Differ ential attacks, or differ ential cryptanalysis Dif ferential cryptanalysis is an attack method tar geting weaknesses in symmetric-k e y block ciphers by e xamining ho w dif ferences in plainte xt inputs af fect the resulting cipherte xts. This technique e xploits the patterns and relationships between dif ferences in plainte xts and their corresponding cipherte xts to g ain insights into the encryption algorithm’ s internal structure. The ultimate goal is to reco v er portions of the secret k e y or to enhance the ef cienc y of brute-force attacks. The success of dif ferential cryptanalysis is highly dependent on the design and structure of the block cipher being tar geted. Process: the Figure 6 sho ws the process of an dif ferential attack. Example of dif ferential cryptanal ysis attack: an attack er encrypts pairs of plainte xts wit h specic dif ferences and observ es the resulting cipherte xt dif ferences. By analyzing ho w these dif ferences propag ate through multiple rounds of a block cipher , such as DES, the attack er can deduce information about subk e ys used in each round, signicantly reducing the k e y search space. Figure 6. Dif ferential attack’ s process 3.1.5. Oracle attacks Oracle attacks in v olv e e xploiting a system that pro vides information about cryptographic operati ons to g ain insights into protected secret information. These att acks le v erage the system’ s responses to queries or operations to e xtract sensiti v e data, such as plainte xt or cryptographic k e ys. Dif ferent types of oracle attacks e xploit v arious aspects of the cryptographic system’ s beha vior , including ho w it handles padding, timing, errors, and ph ysical side-channel information. a. P adding Oracle attacks Scenario: in symmetric encryption schemes that use padding, attack ers submit cipherte xts to an oracle and observ e whether the decrypted plainte xt’ s padding is v alid. Exploitation: by analyzing the oracle’ s responses, attack ers can infer information about the plainte xt and gradually deduce the entire message, le v eraging the patterns in padding v alidity . The Figure 7 sho ws the process of a padding Oracle attack. Figure 7. P adding Oracle attack’ s process Classication of encryption attac ks and str ate gies for mitigation (Anas Maai) Evaluation Warning : The document was created with Spire.PDF for Python.
1244 ISSN: 2252-8776 b . T iming Oracle attacks Scenario: these attacks e xploit v ariations in the time tak en for cryptographic operations to complete. Exploitation: attack ers measure the time it tak es for the system to process cryptographic operations to infer details about the encrypted data or cryptographic k e y . V ariations in processing time can re v eal information about the internal state of the system or specic bits of the k e y . The Figure 8 sho ws the process of a padding Oracle attack. Figure 8. T iming Oracle attacks c. Error -based Oracle attacks Scenario: in v olv es e xploiting error messages generated when cryptographic operations f ail, such as during decryption or v alidation processes. Exploitation: attack ers analyze the content and patterns of error messages to g ain insights into the correctness of parts of the cryptographic input, potentially re v ealing information about the secret k e y or plainte xt. d. Side-channel Oracle attacks Scenario: These attacks e xploit ph ysical information leak ed during the e x ecution of cryptographic algorithms, such as v ariations in po wer consumption, electromagnetic radiation, or acoustic emissions. Exploitation: By observing and analyzing these side-channel leaks, attack ers can infer details about the cryptographic k e y or the internal w orkings of the cryptographic algorithm. The Figure 9 sho ws the side channel Oracle attack. Process: the Figure 10 sho ws the process of a side channel Oracle attack. Symmetric cryptograph y protocols are vulnerable to a wide range of attacks, including brute force, frequenc y analysis, e xhausti v e search, dif ferential, and Oracle attacks. Additional attack types such as replay attacks, meet-in-the-middle attacks, side-channel attacks, kno wn-plainte xt attacks (KP A), and chosen-plainte xt attacks (CP A) further demonstrate the di v ersity of potential threats. Figure 9. Side-channel Oracle attacks Int J Inf & Commun T echnol, V ol. 15, No. 3, September 2026: 1238–1253 Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Inf & Commun T echnol ISSN: 2252-8776 1245 Figure 10. Side-channel Oracle attack’ s process 3.2. Attacks against asymetric cryptograph y pr otocols 3.2.1. F actorization attacks F actorization attacks tar get the prime f actors of public k e ys used in asymmetric cryptographic algo- rithms, such as RSA, with the objecti v e of reco v ering the pri v ate k e y . This type of attack e xploits the math- ematical dif culty of f actoring a lar ge number into its prime components, which is the foundation of RSA s security . The process in v olv es decomposing the public k e y typically a product of tw o lar ge prime numbers into its component primes, thereby enabling the attack er to deri v e the pri v ate k e y . Process: the Figure 11 sho ws the process of a f actorization attack. Example of f actorization a ttack (RSA): an attack er tar gets an RSA public k e y by attempting to f actor the modulus n, which is the product of tw o lar ge prime numbers. If the attack er successfully f actors n into its prime components, the y can compute the pri v ate k e y and decrypt encrypted messages or for ge digital signatures. Historical adv ances in inte ger f actorization algorithms ha v e demonstrated that insuf cient k e y sizes mak e RSA vulnerable to such attacks. Figure 11. F actorization attack’ s process 3.2.2. Exhausti v e sear ch f or pri v ate k eys Exhausti v e Search for Pri v ate K e ys, also kno wn as brute- force search, is a cryptographic attack in which an attack er systematically tests all possible pri v ate k e y combinations to nd the correct one. This method Classication of encryption attac ks and str ate gies for mitigation (Anas Maai) Evaluation Warning : The document was created with Spire.PDF for Python.
1246 ISSN: 2252-8776 is used in asymmetric k e y algorithms and relies on the impracticality of e xhausti v ely searching the entire k e y space due to its v ast size. The feasibility of this attack decreases as the size of the k e y space gro ws, making it increasingly dif cult to disco v er the correct k e y . Process: the Figure 12 sho ws the process of an e xhausti v e search attack. Example of e xhausti v e Search for pri v ate k e ys: an attack er attempts to reco v er an asymmetric pri v ate k e y by systematically testing all possible k e y v alues. Although theoretically possible, the e xtremely lar ge k e y spaces used in modern asymmetric algorithms such as RSA and ECC mak e e xhausti v e s earch attacks computationally infeasible when appropriate k e y lengths are emplo yed. Figure 12. Exhausti v e search’ s process 3.2.3. Collision attacks Collision attacks tar get hash functions with the objecti v e of nding tw o distinct inputs that produce the same output hash v alue, kno wn as a collision. Hash functions are designed to map arbitrary data to x ed- size hash v alues. In a collision attack, the attack er aims to nd tw o dif ferent inputs, M 1 and M 2 , such that H ( M 1 ) = H ( M 2 ) , where H represents the hash function. The ability to nd such collisions undermines the inte grity and security guarantees pro vided by the hash function. Process: the F igure 13 sho ws the proces s of a collision attack. Example of collision attack on hash functions Used in asymmetric cryptograph y: an attack er nds tw o distinct messages that produce the same hash v alue using a weak hash function. In digital signature schemes, this allo ws the att ack er to substitute a le gitimate signed message with a malicious one that has the same hash, thereby undermining message inte grity and authentication in asymmetric cryptographic systems. Figure 13. Collision attack’ s process Int J Inf & Commun T echnol, V ol. 15, No. 3, September 2026: 1238–1253 Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Inf & Commun T echnol ISSN: 2252-8776 1247 3.2.4. T iming analysis attacks T iming analysis attacks are a type of side-channel attack that e xploit v ariations in the time tak en by a cryptographic system to perform specic operations. By measuring t hese time v ariations, attack ers can infer sensiti v e details, such as cryptographic k e ys. These attacks f all under the cate gory of side-channel attacks, which le v erage unintended information leakage from the ph ysical implementation of a cryptographic system. T iming v aria tions can arise due to f actors such as input data, system state, or internal cryptographic processes. The primary objecti v e of timing analysis attacks is to analyze timing dif ferences to re v eal information about the cryptographic k e y or other sensiti v e details. Process: the Figure 14 sho ws the process of a timing analysis attack. Example of RSA timing anal- ysis attack: an attack er measures the time tak en by a serv er to perform RSA pri v ate-k e y operations, such as decryption or signature generation. By analyzing v ariations in e x ecution time correlated with k e y-dependent operations, the attack er can infer information about the pri v ate k e y . This type of attack e xploits implementation weaknesses rather than a ws in the RSA algorithm itself. Figure 14. T iming analysis attack’ s process 3.2.5. Side-channel attacks Side-channel attacks e xploit unintentional information leaks from the ph ysical implementation of a cryptographic system, circumv enting the mathematical rob ustness of the al g or ithms themselv es. These attacks le v erage observ able side-channel information, such as po wer consumption, electromagnetic radiation, e x ecu- tion time, or e v en sound, to infer sensiti v e details such as cryptographic k e ys. By analyzing these unintentional leaks, attack ers can g ain insights into the internal w orkings of the cryptographic system [20]. Common types of side-channel attacks: T iming attacks: e xploit v ariations in the time tak en for cryptographic operations. By measuring the e x ecution time of dif ferent operations, attack ers can infer details about the internal state or k e y material. Po wer analysis attacks: monitor the po wer consumption of a cryptographic de vice during operations. V ari- ations in po wer consumption can be correlated with specic computations, re v ealing information about the cryptographic k e y or intermediate v alues. Electromagnetic analysis attacks: observ e electromagnetic radiation emitted by a cryptographic de vice during operations. The patterns in electromagnetic emissions can pro vide insights into the internal processes and cryptographic k e ys. Acoustic analysis attacks: capture and analyze the sound produced by a cryptographic de vice while it is operating. V ariations in sound patterns can be e xploited to deduce details about cryptographic computations. Cache attacks: e xploit the beha vior of cache memory during cryptographic operations. By analyzing cache access patterns and memory usage, attack ers can infer information about the data being processed. Classication of encryption attac ks and str ate gies for mitigation (Anas Maai) Evaluation Warning : The document was created with Spire.PDF for Python.