what is an otp

An OTP, or one-time password, is a password that is valid for only one login session or transaction on a computer system or other digital device. OTPs are more secure than traditional, static passwords because they are automatically generated and can only be used once, reducing the risk of password theft and replay attacks. OTPs can be numeric or alphanumeric strings of characters that are generated using pseudorandomness or randomness to generate a shared key or seed, and cryptographic hash functions, which can be used to derive a value but are hard to reverse and therefore difficult for an attacker to obtain the data that was used for the hash. OTPs can be used in addition to traditional authentication methods or may replace them entirely to add another layer of security. OTPs can be generated using hardware, software, or on-demand, and can be delivered via SMS, email, or mobile device apps.