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Confirmation code

A confirmation code, also referred to as a verification code, is a temporary sequence of decimal digits delivered to a user via a designated communication channel—such as email, SMS, or postal mail—to demonstrate control over that channel and verify identity during processes like account enrollment, login, or transaction authorization.^[1] This mechanism enhances security in digital systems by requiring the user to return or input the code, confirming possession of the associated contact information without relying solely on static credentials like passwords.^[1] In multi-factor authentication (MFA) frameworks, confirmation codes typically function as the second authentication factor, adding a layer of protection after initial password entry to prevent unauthorized access by entities lacking physical or channel-specific control.^[2] Standards from the National Institute of Standards and Technology (NIST) specify that these codes must be at least six decimal digits long, generated from an approved random bit generator, and invalidated after a single use, with validity periods varying by delivery method: up to 10 minutes for SMS or voice calls, 24 hours for email, and 21 to 30 days for postal delivery.^[1] They are integral to identity assurance levels (IAL1 and IAL2), where they support binding authenticators to a subscriber's identity and mitigate risks like impersonation during enrollment.^[1] Beyond authentication, confirmation codes facilitate secure account creation by deterring automated abuse and fake registrations, as well as authorizing high-value transactions in e-commerce and financial services.^[1] However, they are vulnerable to social engineering attacks, where fraudsters impersonate legitimate entities to solicit the code and gain account access; users are advised never to share it and to report suspicious requests to authorities.^[3]

Definition and Fundamentals

Definition

A confirmation code is a short, often temporary piece of data, such as an alphanumeric string, cipher, or token, used to verify a specific attribute, identity, or action, including confirming email ownership or transaction legitimacy.^[4]^[5] These codes provide an additional layer of assurance that the intended user or process is authenticating correctly.^[6] Standards such as NIST SP 800-63 specify requirements for their generation, length, and validity to ensure security in authentication processes.^[1] Key characteristics of confirmation codes include their typical length of 6-10 characters (or more), which balances usability and security by limiting guessability while remaining easy to enter.^[7]^[8] They are time-limited, generally expiring within minutes to hours—often 5-10 minutes—to minimize the window for interception or reuse.^[9]^[10] Confirmation codes are generated algorithmically, using methods like random number generators, hash functions, or time-based one-time password (TOTP) algorithms to ensure uniqueness and unpredictability.^[11] They are transmitted through secure channels, such as SMS, email, or dedicated mobile applications, to reach the intended recipient without interception.^[5]^[12] Unlike static, reusable passwords that users memorize for repeated access, confirmation codes are designed for one-time or session-specific use, reducing risks from long-term exposure.^[3] In contrast to longer-term cryptographic keys, which are paired with algorithms for ongoing data encryption or decryption, confirmation codes focus on ephemeral verification rather than persistent security operations.^[13] Confirmation codes often function as a component in multi-factor authentication systems.^[14]

Historical Origins

One of the earliest recorded examples of a verification mechanism is the biblical "shibboleth," derived from a narrative in the Book of Judges 12:5-6, dated to approximately the 12th century BCE. In this account, Gileadite forces used the pronunciation of the Hebrew word "shibboleth" (meaning "ear of corn" or "stream") as a verbal test to distinguish Ephraimite intruders, who could only say "sibboleth" due to their dialectal differences, resulting in the identification and execution of 42,000 Ephraimites.^[15] This episode represents one of the earliest recorded uses of a linguistic passphrase as a confirmation mechanism for group verification in a conflict setting.^[16] Pre-digital confirmation methods evolved through military and tribal practices, where oral watchwords served to authenticate allies and exclude adversaries. In ancient Rome, starting from the Republic era around the 3rd century BCE, legionaries employed daily "watchwords" (known as tessera), wooden tablets inscribed with a secret phrase passed among sentinels to verify identities during night patrols and camp entries.^[17] This system persisted into medieval Europe, where knights and guards at fortifications used rotating verbal passwords or challenges to control access to castles and battlements, often changed nightly to prevent infiltration.^[18] By the 19th and 20th centuries, these evolved into cryptographic systems for espionage, such as one-time pads used during World War II for secure agent communications, which exemplified the principle of unique, non-repeating keys and influenced modern one-time-use verification methods, as adopted by the British Special Operations Executive in 1943 to replace less secure ciphers.^[19] The shift to digital confirmation codes began in the mid-20th century with computing advancements. In 1967, the first automated teller machine (ATM), installed by Barclays in London, introduced personal identification numbers (PINs) as a simple numeric code for user verification to dispense cash, marking an early electronic authentication method in banking. By the 1970s, PIN-like codes and basic passwords were integrated into computer terminal access for mainframes and early networks, enabling secure logins in academic and military environments.^[17] In the 1990s, internet protocols extended this to email-based verification; for instance, LISTSERV software implemented the first confirmed opt-in mechanism in 1993, requiring subscribers to respond to a confirmation email for mailing list enrollment, laying groundwork for account validation in web services.^[20]

Types and Mechanisms

Visual and Interactive Codes (e.g., CAPTCHA)

Visual and interactive confirmation codes leverage human perceptual and cognitive abilities to differentiate users from automated bots, exploiting gaps in artificial intelligence's pattern recognition and problem-solving capabilities. These codes present challenges such as distorted text, image-based puzzles, or interactive tasks that are straightforward for humans but computationally difficult for machines without significant resources. The core mechanism involves generating a unique challenge on the server side, displaying it to the user via a web interface, and requiring input that verifies human interaction, thereby confirming the user's legitimacy in real-time. CAPTCHA, or Completely Automated Public Turing test to tell Computers and Humans Apart, exemplifies this approach and was invented in 2000 by Luis von Ahn, Manuel Blum, Nicholas J. Hopper, and John Langford at Carnegie Mellon University.^[21] Initially focused on distorted text recognition to block bots from creating email accounts or posting spam, CAPTCHA evolved into reCAPTCHA in 2007, also by von Ahn and colleagues, which repurposed user responses to aid in digitizing books through human-assisted optical character recognition. Key variants include reCAPTCHA v1 (2007), relying on text-based distortions; reCAPTCHA v2 (2014), featuring image selection challenges like identifying objects in grids following an "I'm not a robot" checkbox; and reCAPTCHA v3 (2018), which incorporates invisible behavioral analysis for risk scoring without overt user interaction.^[22] These systems primarily prevent automated abuse in online forms, user registrations, and search functionalities by ensuring responses come from humans rather than scripts.^[23] Generation of these codes typically occurs server-side, where challenges are rendered dynamically to avoid predictability; for instance, text CAPTCHAs apply distortions like warping, noise, and color variations using image processing techniques. Validation follows user submission, comparing the response against the original challenge—often via a simple string equality check, case-insensitively, or hashed for security—before granting access or proceeding with the action.^[24] In practice, libraries such as Python's Pillow facilitate the creation of these visual elements by manipulating images to introduce the necessary obfuscation.^[25] Such codes can serve as an additional layer in multi-factor authentication processes.^[26]

Text-Based Codes (e.g., OTPs and PINs)

Text-based confirmation codes consist of character strings, typically numeric or alphanumeric, that users enter to verify identity or authorize actions securely. These codes prioritize ease of transmission via channels like SMS, email, or apps, while relying on cryptographic generation to resist prediction and reuse. Common lengths include 4 to 8 digits, balancing memorability or readability with security against brute-force attacks.^[27] The core mechanism involves generating pseudo-random strings using standardized algorithms that leverage shared secrets and dynamic inputs. For instance, one-time passwords (OTPs) often employ the HMAC-based one-time password (HOTP) algorithm, which produces a code from a symmetric key and counter to ensure event-based uniqueness. This approach, formalized in RFC 4226 published in December 2005, computes the value as follows:

\text{HOTP}(K, C) = \text{Truncate}(\text{HMAC-SHA1}(K, C))

where K is the shared secret key, C is the incrementing counter, HMAC-SHA1 generates a hash, and Truncate extracts a fixed-length output, such as 6 digits.^[28] A time-based variant, the time-based one-time password (TOTP), extends HOTP by incorporating the current timestamp for synchronization without needing a shared counter. Defined in RFC 6238 from May 2011, TOTP generates codes valid for short intervals, typically 30 seconds:

\text{TOTP}(K, T) = \text{HOTP}(K, T), \quad T = \left\lfloor \frac{\text{UnixTime} - T_0}{X} \right\rfloor

with T_0 as the epoch start (often 0) and X = 30 seconds; this ensures codes expire quickly, reducing replay risks.^[29] OTPs serve as single-use verifiers, enhancing authentication beyond static passwords. In banking, they gained prominence for securing online transactions, with SMS delivery becoming widespread in the early 2000s to mitigate phishing by providing transient approvals.^[30] Applications like Google Authenticator, released on September 20, 2010, popularized app-based TOTP generation, allowing offline code production from a provisioned secret.^[31] Personal identification numbers (PINs) represent another key variant, functioning as fixed, context-specific codes that users enter repeatedly for access within defined scopes, such as device unlocks or point-of-sale terminals. Typically 4 digits long, PINs originated with automated teller machines (ATMs); the first such system, installed by Barclays Bank in London on June 27, 1967, required a punched-card encoded with a radioactive-ink PIN for cash withdrawal.^[32] Modern PINs are either user-chosen during setup or randomly assigned by systems, then validated server-side against hashed versions stored securely to protect against data breaches.^[33] This hashing, often using algorithms like bcrypt or Argon2 adapted for short inputs, ensures irreversibility while allowing efficient comparison during entry.

Behavioral and Contextual Codes

Behavioral and contextual codes represent a class of implicit verification mechanisms that derive confirmation signals from observable user behaviors or surrounding environmental factors, enabling authentication without requiring explicit user input. These methods analyze patterns such as keystroke dynamics—measuring typing speed, rhythm, and pressure—or mouse movement trajectories to create unique behavioral profiles that serve as dynamic "codes" for identity confirmation. Similarly, contextual elements like device fingerprints, which aggregate attributes such as browser headers, screen resolution, and installed fonts, or IP geolocation data, provide passive indicators of legitimacy by establishing a baseline for expected session environments. Machine learning models, including support vector machines (SVM) for anomaly detection, process these inputs to classify behaviors as normal or suspicious, often achieving detection rates above 90% in controlled studies on keystroke biometrics. Risk-based authentication systems exemplify behavioral and contextual codes by dynamically adjusting verification intensity based on inferred risk levels from user patterns and context, thereby reducing user friction in low-risk scenarios. Device binding codes further this approach by linking authentication sessions to hardware-specific identifiers, such as universally unique identifiers (UUIDs) in mobile applications, ensuring that confirmation is tied to a trusted device without ongoing user interaction. These techniques prioritize seamless verification, with studies showing that behavioral profiling can reduce false positives in authentication by up to 25% compared to static methods. As of 2025, behavioral biometrics are increasingly integrated with passwordless standards like FIDO2, enhancing implicit verification in multi-factor setups.^[34] Generation of these codes typically involves server-side processing where raw behavioral or contextual data is transformed into hashed tokens for validation. For example, a contextual hash might combine the user agent string—detailing browser type and version—with a timestamp and geolocation coordinates, then apply a cryptographic function like SHA-256 to produce a verifiable token that matches against a pre-stored profile without alerting the user. Validation occurs transparently on the backend, flagging deviations such as unusual typing cadences or mismatched device fingerprints as potential threats. Google's Advanced Protection Program, launched in 2017, incorporates such device context for code-less confirmation, using signals like hardware attestation and network provenance to authorize access, which has been credited with enhancing security for high-risk users by integrating these implicit codes into broader multi-factor setups.

Applications and Use Cases

In User Authentication and Verification

Confirmation codes are integral to user authentication and verification, serving as a secondary factor to confirm identity during account registration and login on digital platforms. A primary application involves email confirmation links, which are unique, clickable URLs embedded with cryptographically secure tokens generated upon registration. These links, sent via email protocols such as SMTP, allow users to verify ownership of the provided address, thereby preventing automated or fraudulent sign-ups. This practice aligns with established security guidelines for identity management, where verification ensures the email is both valid and controlled by the registrant.^[35] Two-factor authentication (2FA) represents another foundational use, combining a primary credential like a password with a time-sensitive confirmation code to authenticate users, particularly during logins from unfamiliar devices or sessions. These codes, often delivered via SMS or authenticator apps, add a possession-based factor to mitigate risks from compromised passwords. For instance, Facebook rolled out 2FA in 2011, enabling users to receive six-digit SMS codes for approving access from new devices.^[36] Many contemporary 2FA flows extend authorization protocols like OAuth 2.0, standardized in 2012, and its extensions such as PKCE (introduced in 2015) by incorporating code challenges within the token exchange process to enforce multi-step verification.^[37]^[38] The underlying process for these confirmation mechanisms begins at the point of user registration or login initiation, where the system generates a one-time token or code, typically hashed for storage in a dedicated database table alongside metadata such as the user's identifier and a timestamp for expiration—often set to 15-30 minutes to limit exposure windows. Delivery occurs through secure channels like encrypted email or SMS gateways, after which the user submits the code or activates the link. Verification involves a backend query, such as a secure database lookup (e.g., matching the token hash against the stored value while checking for expiration and single-use flags), to approve or deny the action. This workflow, recommended in authentication best practices, ensures robust identity proofing without storing sensitive delivery details long-term.^[35] Case studies illustrate widespread adoption in diverse ecosystems. In social media, Facebook's SMS-based 2FA, introduced in 2011, exemplifies user-centric verification by prompting codes for suspicious logins.^[36] In enterprise settings, Microsoft's Azure Active Directory implemented multi-factor authentication with confirmation codes in 2013.^[39] These implementations highlight how confirmation codes enable scalable identity verification across platforms.

In Transaction and Account Security

Confirmation codes play a critical role in transaction and account security by providing an additional layer of verification for sensitive financial activities, such as payments and account modifications, thereby reducing the risk of unauthorized access and fraud beyond initial login processes. These codes ensure that only authorized users can approve high-risk operations, often integrating with multi-factor authentication mechanisms to confirm identity during dynamic events like fund transfers or profile changes. In payment verifications, confirmation codes are integral to protocols like 3D Secure, introduced by Visa in 2001 as Verified by Visa (VBV), which requires users to enter a one-time code for online card transactions to authenticate the cardholder with the issuer.^[40] Mastercard adopted a similar approach with SecureCode (MCSC), mandating these codes for e-commerce purchases to mitigate card-not-present fraud by shifting liability to issuers upon successful verification.^[41] For account recovery, password reset codes sent via email serve as temporary authenticators, allowing users to regain access while incorporating rate limiting to thwart brute-force attacks and automated abuse in banking systems.^[42] Transaction signing processes leverage confirmation codes through standards like EMV, developed in the 1990s and first specified in 1996, where chip cards generate dynamic card verification values (CVVs) for each transaction using cryptographic algorithms to prevent replay attacks and ensure data integrity.^[43] In high-value actions, such as wire transfer approvals in banking apps, biometric-linked codes combine fingerprint or facial recognition with one-time passcodes, requiring dual approval to authorize transfers over predefined thresholds, as recommended in federal guidelines for secure wire handling.^[44] In e-commerce, PayPal employs one-time passcodes (OTPs) as part of its multi-factor authentication for buyer protection during transactions, verifying user identity before finalizing payments to cover eligible items up to the full purchase price in case of disputes or non-delivery.^[45] For cryptocurrency wallets, Ledger's hardware devices, launched in 2014, use seed-derived confirmation codes from the 24-word recovery phrase to authorize transactions, ensuring private keys remain secure on the device without exposure during signing.^[46]

In System and Device Confirmation

Confirmation codes play a crucial role in verifying the integrity and authenticity of interactions between software systems, hardware devices, and automated processes, ensuring secure machine-to-machine (M2M) communications without human intervention. In API endpoint verifications, such as those in RESTful services, OAuth 2.0 access tokens serve as short-lived confirmation codes that authorize requests by confirming the caller's identity and permissions. These tokens, typically valid for short durations like one hour, are issued by an authorization server and validated by the resource server through introspection or JWT decoding, preventing unauthorized access to endpoints.^[47] Device pairing mechanisms further exemplify system confirmation, particularly in wireless protocols like Bluetooth, where numeric comparison codes facilitate secure association. Standardized in the Bluetooth 2.1 specification released in 2007, this method generates a six-digit code from elliptic curve Diffie-Hellman key agreement; both devices display the code, and successful pairing requires implicit confirmation via matching values, mitigating man-in-the-middle attacks in M2M setups.^[48] In M2M confirmation processes, protocols like SSL/TLS employ challenge-response mechanisms during the handshake to validate certificates and establish session keys. The client and server exchange random nonces as challenges, which are incorporated into digital signatures using the server's private key; the client verifies the signature against the public key in the certificate, confirming the server's identity before proceeding to symmetric encryption. This process, integral to TLS since version 1.0 in 1999, ensures endpoint authenticity in automated data exchanges.^[49] For IoT setups, Zigbee networks utilize 128-bit symmetric keys truncated to authentication codes during device joins, enabling secure network integration. The network key, distributed by the trust center coordinator in an encrypted frame using AES-128-CCM*, includes a 32-bit message integrity code (MIC) derived from the full key material; joining devices validate this code to confirm key receipt and authenticate the join request, preventing unauthorized entry into the mesh topology.^[50] Case studies in cloud computing highlight temporary security tokens for role-based confirmations, as seen in AWS Identity and Access Management (IAM) introduced in 2011. AWS Security Token Service (STS) generates short-lived credentials, such as access keys valid up to 12 hours, which applications assume for roles to verify permissions in M2M API calls, enhancing security by limiting exposure compared to long-term keys. Similarly, firmware updates leverage secure boot chains in the Unified Extensible Firmware Interface (UEFI), specified starting in version 2.0 around 2006 with Secure Boot formalized in 2.3.1 by 2011. UEFI uses digital signatures and hash confirmations: each boot stage computes a hash of the next component's image, verifies it against a signature using platform keys, and chains trust from the root to the OS loader, ensuring only authorized firmware executes.^[51]^[52]

Security and Implementation

Common Vulnerabilities

Confirmation codes are susceptible to phishing and interception attacks, where adversaries exploit delivery channels to capture codes in transit. SIM swapping, a prevalent interception method, involves fraudulently transferring a victim's phone number to an attacker's SIM card, enabling receipt of SMS-delivered confirmation codes. A notable example occurred in 2019 when hackers used SIM swapping to hijack Twitter CEO Jack Dorsey's phone number, allowing them to access two-factor authentication codes and post unauthorized tweets from his account.^[53]^[54] Similarly, man-in-the-middle (MitM) attacks on email channels can intercept unencrypted or poorly secured confirmation codes by positioning the attacker between the user and the server, capturing codes during transmission.^[55]^[56] Brute-force and prediction attacks target the limited entropy of confirmation codes, making them feasible to crack through systematic guessing. Short codes, such as 4-digit PINs, offer only 10,000 possible combinations, rendering them vulnerable to automated brute-force attempts that can exhaust the keyspace in seconds on modern hardware.^[57] For time-based one-time passwords (TOTPs), clock desynchronization between the client device and server can enable predictive attacks, as codes remain valid within a tolerance window (typically 30 seconds plus drift allowance), allowing attackers to generate and test multiple candidate codes if they estimate the offset.^[58] Social engineering exploits human behavior to obtain confirmation codes directly from users. Shoulder surfing, particularly against visual codes like CAPTCHAs or graphical challenges, occurs when an observer covertly watches a user input the code on a screen or device in public settings, capturing the sequence without technical tools.^[59] Pretexting, a deceptive tactic, involves attackers fabricating urgent scenarios—such as posing as support staff—to trick users into sharing codes verbally or digitally.^[60] The 2016 Yahoo data breaches exemplified risks to verification flows, where hackers accessed over 500 million accounts' details, including unencrypted security questions and phone numbers, enabling targeted social engineering to bypass or intercept subsequent confirmation steps.^[61]^[62]

Best Practices and Standards

Implementing confirmation codes securely requires adherence to established guidelines that emphasize randomness, secure transmission, and integration with robust protocols. A key principle is ensuring sufficient entropy in code generation to resist brute-force attacks; for instance, one-time passwords (OTPs) used in authentication should incorporate at least 20 bits of entropy to meet assurance level AAL1 requirements, as specified in NIST Special Publication 800-63B.^[63] This can be achieved through cryptographically secure pseudorandom number generators, limiting the predictability of codes even if an attacker intercepts partial information. Additionally, implementers should enforce short expiration times—typically 5 to 10 minutes—and rate limiting on submission attempts to mitigate risks from phishing or replay attacks, aligning with these entropy standards.^[63] Channel selection plays a critical role in preventing interception vulnerabilities, with recommendations favoring out-of-band methods less susceptible to compromise. The FIDO Alliance advocates for app-based authenticators or push notifications over SMS-based delivery, as the latter is prone to SIM swapping and network interception, thereby promoting phishing-resistant alternatives for multi-factor authentication flows. For example, in February 2025, Google announced it would replace SMS codes with QR codes for Gmail authentication to reduce the impact of global SMS abuse and vulnerabilities.^[64] Diversity in delivery channels, such as combining email with authenticator apps, further enhances resilience by avoiding single points of failure, while always verifying user possession through device-bound mechanisms. Standards provide a framework for integrating confirmation codes into broader authentication ecosystems. RFC 6749, the OAuth 2.0 Authorization Framework, outlines how authorization codes can be used as temporary, bearer tokens to securely exchange credentials between clients and servers, ensuring they are single-use and transmitted over TLS to prevent eavesdropping.^[37] Complementing this, the WebAuthn specification from the W3C enables passwordless confirmation through public-key cryptography, where challenges are signed by authenticators like hardware tokens or biometrics, offering strong resistance to phishing without relying on shared secrets. Emerging trends are shifting toward passwordless and future-proof designs to address evolving threats. Passkeys, introduced in iOS 16, represent a passwordless authentication method using cryptographic key pairs synced via iCloud Keychain, allowing seamless, biometric-enabled confirmation across devices while eliminating the need for transmitted codes.^[65] In parallel, preparations for quantum-resistant confirmation codes are underway, with NIST releasing initial post-quantum encryption standards in 2024, including algorithms like CRYSTALS-Kyber (now ML-KEM) for key encapsulation, and selecting HQC as a fifth algorithm in March 2025 to further safeguard against quantum computing attacks on current elliptic curve-based systems.^[66]^[67] These advancements encourage adoption of hybrid schemes that layer classical and post-quantum protections during the transition period.

References

[1]
NIST Special Publication 800-63A
Aug 26, 2025 · The CSP employs an approved identity verification process to confirm that the applicant is the genuine owner of the presented identity evidence.
[2]
Project Upskill Glossary | CISA
MFA usually includes a password and at least one other step, such as text message email confirmation code, or the use of an authenticator app, for ...<|control11|><|separator|>
[3]
What's a verification code and why would someone ask me for it?
Mar 7, 2024 · A verification code is used to confirm your identity when logging in. Scammers ask for it to access your account, and you should never give it ...
[4]
What is Confirmation Code: 5 Things You Need to Know About It
Mar 30, 2021 · It is commonly known that a confirmation code is a piece of data that is mainly used to confirm the necessary information, especially a certain ...
[5]
What Is a Verification Code? - 123FormBuilder Blog
Feb 22, 2024 · Verification codes are alphanumeric or numeric codes that are texted, emailed, or forwarded to a second device to confirm an account holder's identity.
[6]
authentication code: Definition, Examples, and Applications | Graph AI
An authentication code is a temporary security code used to verify a user's identity during the login process, often as part of two-factor authentication.
[7]
Verify C# ASP.NET Core Quickstart | Twilio
With the Verify API. Services can be used to edit the name (which shows up in the message template), set the code length (4-10 characters) ...
[8]
Two factor authentication: expiry of sent text message
Oct 26, 2017 · The most common time frames are between 5 and 10 minutes. Depending on what your code is for, you can change the expiration times.
[9]
How does the verification code service time? - Tencent Cloud
Jun 10, 2025 · Expiration: The code is valid only for a limited duration, usually ranging from 1 to 10 minutes, depending on the service's security policies.Missing: confirmation | Show results with:confirmation
[10]
Just How Random Are Two Factor Authentication Codes? - WIRED
Apr 21, 2018 · Google Authenticator generates codes using the Time-Based One Time Password Algorithm. And because TOTP is an open standard, most other 2FA ...Missing: confirmation | Show results with:confirmation
[11]
SMS-based user sign-in for Microsoft Entra ID
Jun 18, 2025 · To complete the sign-in process, enter the 6-digit code provided in the SMS message at the sign-in prompt. Enter the SMS confirmation code sent ...
[12]
Cryptographic Keys 101: What They Are & How They Secure Data
Jun 14, 2023 · A cryptographic key is a string of characters (often random or mathematically generated) that's paired with a cryptographic algorithm to secure data.Cryptographic Keys 101: What... · Symmetric Keys = A Single... · Asymmetric Keys = Separate...<|control11|><|separator|>
[13]
MFA Vs 2FA: How To Choose The Best Authentication Method For ...
Authentication means a user must prove their identity before they are ... confirmation code, followed by a scan of your fingerprint on a physical device.
[14]
Shibboleth - Brill Reference Works
The English word shibboleth has its origins in an episode narrated in Judg. 12.1–6. The story there revolves around the Hebrew word שִׁבֹּלֶת šibbōlεṯ, ...<|separator|>
[15]
The Shibboleth Incident (Judges 12:5-6) as a Migratory Narrative ...
Aug 15, 2025 · The term and the concept originate in a short passage in the Old Testament of the Bible, Book of Judges, chapter 12, verses 5 and 6 – called The ...
[16]
Passwords have a long history – how much do you know…?
Jun 8, 2024 · Passwords evolved from Roman watchwords, to challenge-response systems, first used at MIT in 1960, and now use hashing and salting. Short ...
[17]
Medieval Cybersecurity: Ancient Tactics for Digital Defenses
Medieval fortifications and military camps employed rotating watchwords, which were changed frequently to ensure security. Guards were required to know the ...
[18]
One-time-pad - Cipher Machines and Cryptology
In 1943, one-time pads became the main cipher of the Special Operations Executive (SOE) to replace insecure poem-based transposition ciphers and book ciphers.Origins of One-time Pad · One-time Letter Pad · One-time Figure Pad
[19]
Internet and Email History Timeline - L-Soft
1993. The first double opt-in/confirmed opt-in feature for email lists introduced in LISTSERV: Automatic confirmation request of all subscriber mailing list ...
[20]
[PDF] Telling Humans and Computers Apart (Automatically)
It requires a test (or a set of tests) that computers can grade, humans can pass, but paradoxically, computers can't pass. In our lingo, it requires a captcha.
[21]
Choosing the type of reCAPTCHA - Google for Developers
Jul 10, 2024 · reCAPTCHA v3 allows you to verify if an interaction is legitimate without any user interaction. It is a pure JavaScript API returning a score.
[22]
reCAPTCHA website security and fraud protection | Google Cloud
reCAPTCHA provides multiple methods to verify that a user is human, including invisible verification, risk-based scoring, and visual challenges. Since 2020 ...
[23]
How CAPTCHAs work | What does CAPTCHA mean? - Cloudflare
A CAPTCHA test is designed to determine if an online user is really a human and not a bot. CAPTCHA is an acronym that stands for "Completely Automated Public ...
[24]
Program to generate CAPTCHA and verify user - GeeksforGeeks
Apr 3, 2023 · The task is to generate unique CAPTCHA every time and to tell whether the user is human or not by asking user to enter the same CAPTCHA as generated ...
[25]
What Does CAPTCHA Mean? | CAPTCHA Types & Examples
CAPTCHAs are used to differentiate between real users and bots. Learn about different CAPTCHA mechanisms and their effect on the user experience on your site.
[26]
HOTP Algorithm Explained - Protectimus Solutions
Mar 16, 2020 · HOTP is a HMAC-based one-time password algorithm using a secret key and counter. It creates a hash, then shortens it to a 6-8 digit OTP.
[27]
RFC 4226 HOTP: An HMAC-Based One-Time Password Algorithm
The HOTP algorithm is based on an increasing counter value and a static symmetric key known only to the token and the validation service. In order to create the ...
[28]
RFC 6238 - TOTP: Time-Based One-Time Password Algorithm
This document describes an extension of the One-Time Password (OTP) algorithm, namely the HMAC-based One-Time Password (HOTP) algorithm, as defined in RFC 4226.
[29]
SMS-based one-time passwords: attacks and defense
SMS-based One-Time Passwords (SMS OTP) were introduced to counter phishing and other attacks against Internet services such as online banking.
[30]
Google Authenticator now supports Google Account synchronization
Apr 24, 2023 · We released Google Authenticator in 2010 as a free and easy way for sites to add “something you have” two-factor authentication (2FA) that ...
[31]
The man who really invented the cash machine - BBC
Jun 27, 2017 · James Goodfellow, who will be 80 this year, is the man who first patented automated cash machines that use pin numbers - but for years the only ...
[32]
Password Storage - OWASP Cheat Sheet Series
Use Argon2id or scrypt for modern password storage. Hash passwords, not encrypt. Use salting, and consider peppering for added security.Missing: PIN | Show results with:PIN
[33]
Authentication - OWASP Cheat Sheet Series
A confirmation-required email message to the proposed new address, instructing the user to confirm the change and providing a link for unexpected situations.Multifactor Authentication · Password Storage · Session Management
[34]
Facebook intros two-factor authentication to beef up security
Apr 25, 2011 · Facebook has begun introducing two-factor authentication designed to prevent hackers from accessing users' accounts.
[35]
RFC 6749 - The OAuth 2.0 Authorization Framework
The OAuth 2.0 authorization framework enables a third-party application to obtain limited access to an HTTP service, either on behalf of a resource owner.Oauth · RFC 2617 - HTTP Authentication · RFC 5849 · Bearer Token Usage
[36]
Microsoft defends Azure with two-factor auth security - The Register
Sep 26, 2013 · Users can authenticate via an application on their mobile device, an automated voice call, or a text message. The technology was introduced in ...
[37]
3D Secure Authentication Explained - GoCardless
What is 3D secure authentication? First launched in 2001 by Visa, 3D secure authentication is now widely used by all major credit and debit card issuers.
[38]
[PDF] Study of Online Banking Security Mechanism in India - IOSR Journal
• 3D Secure (Verified by Visa (VbV)/ MasterCard SecureCode (MCSC))-In event of any unusual activity e.g change of IP address etc in your Internet Banking ...
[39]
Forgot Password - OWASP Cheat Sheet Series
Send the user an email informing them that their password has been reset (do not send the password in the email!). ... rate limiting. If required, perform any ...
[40]
[PDF] EMV® Chip At-a-Glance - EMVCo
By 1994, all French bank cards carried a chip using a French developed specification for chip card credit and debit payment, which dramatically reduced fraud ...Missing: CVV | Show results with:CVV
[41]
[PDF] WIRE TRANSFERS Core Analysis Decision Factors - FDIC
Introduction: Consider whether wire transactions are securely transmitted. Relevance: Secure networks will maintain the confidentiality and integrity of data ...<|control11|><|separator|>
[42]
PayPal's Purchase Protection Program
Sep 2, 2025 · PayPal's Purchase Protection program may result in coverage for the full purchase price of the item plus the original shipping costs you paid, if any.Missing: OTP 1998
[43]
Recovery Check - Ledger Support
Oct 24, 2025 · Use the Recovery Check app on your Ledger device to verify that you've correctly backed up your Secret Recovery Phrase on your Recovery ...Missing: derived 2014
[44]
Access Tokens - OAuth 2.0 Simplified
Aug 17, 2016 · Access tokens are the thing that applications use to make API requests on behalf of a user. The access token represents the authorization of a specific ...Refreshing Access Tokens · Self-Encoded Access Tokens · Access Token Response
[45]
Part H Security Manager Specification - Bluetooth
Authentication stage 1 – Just Works or Numeric Comparison. The Numeric Comparison association model will be used during pairing if the MITM bit is set to 1 ...
[46]
What happens in a TLS handshake? | SSL handshake - Cloudflare
A TLS handshake enables clients and servers to establish a secure connection and create session keys. Learn more about how a TLS vs SSL handshake works.What is an SSL certificate? · How does SSL work? · How does keyless SSL work?
[47]
Concepts | Zigbee Security - Developer Docs - Silicon Labs
Zigbee uses a 128-bit symmetric key to encrypt all transmissions at the network layer using AES-128. The network and auxiliary headers are sent in the clear but ...
[48]
Temporary security credentials in IAM - AWS Documentation
You can use AWS Security Token Service (AWS STS) to create and provide trusted users with temporary security credentials that can control access to your AWS ...Request temporary security... · Managing AWS STS in an AWSMissing: 2006 | Show results with:2006
[49]
32. Secure Boot and Driver Signing - UEFI Forum
In order to verify a signature, two pieces of data are required: the original message and the public key. First, the hash must be calculated exactly as it was ...Missing: 2007 | Show results with:2007
[50]
Hack of Jack Dorsey's Twitter account highlights SIM swapping threat
Sep 6, 2019 · Companies' motives aren't in a place where they favor security over usability." Twitter hackers are using sim cards to attack ... SIM swap attacks ...
[51]
Hackers Hit Twitter C.E.O. Jack Dorsey in a 'SIM Swap.' You're at ...
Sep 5, 2019 · Victims have complained that after the attacks, they have struggled to get help from their phone companies, or to even get someone on the line ...
[52]
What Is a Man-in-the Middle (MITM) Attack? Types & Examples
A man-in-the-middle (MITM) attack occurs when criminals hijack web protocols to steal data. Discover how does a MITM attack works and how to protect ...
[53]
How to Prevent Man-in-the-Middle Attacks - HYPR Blog
Mar 31, 2022 · Email Hijacking. This is a man-in-the-middle attack where the attacker gains access to a user's email, usually through a phishing attack.5. Public Wifi Eavesdropping · 7. Https Spoofing · How Passwordless Mfa...
[54]
Brute Force Attack - FS.com
May 12, 2025 · Take, for instance, a 4-digit password comprising only digits, offering a maximum of 10,000 possible combinations. In such cases, the decryption ...
[55]
token - Does the TOTP Algorithm rely on the client time always being ...
Nov 9, 2017 · TOTP codes are valid for longer than the amount of time they show on the screen (usually two or more times longer).Can displaying date and time on screen upon TOTP login failure ...Is it common for a One-Time-Password system to become ...More results from security.stackexchange.com
[56]
Understanding Shoulder Surfing and How to Prevent It
Sep 10, 2024 · Shoulder surfing is a form of physical data theft where an attacker steals sensitive information by observing a victim's actions in public or semi-public ...Missing: confirmation CAPTCHA
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What Is Pretexting? Definition, Examples and Attacks - Fortinet
Pretexting is a form of social engineering tactic used by attackers to gain access to information, systems, or services by creating deceptive scenarios.
[58]
Yahoo Says Hackers Stole Data on 500 Million Users in 2014
Sep 22, 2016 · Yahoo announced on Thursday that the account information of at least 500 million users was stolen by hackers two years ago.
[59]
Yahoo Hack Leaves One Billion Accounts Compromised | WIRED
Dec 14, 2016 · Yahoo announced on Wednesday that hackers, in what's likely a separate attack, compromised one billion of the company's user accounts in August 2013.
[60]
[PDF] Digital Identity Guidelines: Authentication and Lifecycle Management
Jul 24, 2025 · This document defines technical requirements for each of the three authenticator assurance levels. This publication supersedes corresponding ...
[61]
Passkeys: Passwordless Authentication - FIDO Alliance
Explore passkeys and how they provide phishing-resistant, passwordless login with faster sign-in and enhanced security. Start your passkey implementation.Alliance Overview · FIDO Certification Programs · FIDO Certified Showcase
[62]
iOS 16 is available today - Apple
Sep 12, 2022 · Designed to replace passwords, passkeys use Touch ID or Face ID for biometric verification, and iCloud Keychain to sync across iPhone, iPad, Mac ...A More Personal, Beautiful... · Visual Look Up And Live Text... · More Secure Browsing In...
[63]
NIST Releases First 3 Finalized Post-Quantum Encryption Standards
Aug 13, 2024 · The fourth draft standard based on FALCON is planned for late 2024. While there have been no substantive changes made to the standards since the ...