Pseudorandom Number Generator (PRNG)
Updated Aug 1, 2026
A pseudorandom number generator (PRNG) is an algorithm that produces a sequence of numbers that appears random but is generated by a deterministic process. Starting from an initial value called a seed, the algorithm applies a fixed mathematical formula to produce each subsequent number. Given the same seed, a PRNG always produces the same sequence.
Key facts
PRNGs are deterministic. The output only looks random. Anyone who knows the seed and the algorithm can reproduce the entire sequence.
A cryptographically secure PRNG (CSPRNG) is a PRNG built to resist prediction, even by an attacker who sees part of the output sequence. Standard PRNGs used in general-purpose software are not secure enough for cryptographic use.
A true random number generator (TRNG) is different from a PRNG. A TRNG draws entropy from a physical process and is not deterministic. When a Tangem wallet is created, a true random number generator (TRNG) on a secure element generates the private key, avoiding reliance on deterministic PRNGs for key creation.
Random number generation quality is critical to private key security. A weak or predictable PRNG can allow an attacker to reconstruct private keys, as happened in the 2013 Android SecureRandom vulnerability.
Random number generation also underlies seed phrase creation in software wallets. The software generates a large random number called entropy, which is then converted into a sequence of words from the BIP39 word list. Tangem's default setup skips this by storing keys directly in a secure chip, with BIP39 phrases available optionally.
Non-custodial wallets, including hardware wallets, depend on strong randomness at key generation, since the private key it produces is the sole basis of ownership.
