Bharatiya Nagarik Suraksha Sanhita, 2023
Section 334
Previous conviction or acquittal how proved
In any inquiry, trial or other proceeding under this Sanhita, a previous conviction or acquittal may be proved, in addition to any other mode provided by any law for the time being in force,—
(a) by an extract certified under the hand of the officer having the custody of the records of the Court in which such conviction or acquittal was held, to be a copy of the sentence or order; or
(b) in case of a conviction, either by a certificate signed by the officer in charge of the jail in which the punishment or any part thereof was undergone, or by production of the warrant of commitment under which the punishment was suffered, together with, in each of such cases, evidence as to the identity of the accused person with the person so convicted or acquitted.
Why this exists
Prior convictions can matter for sentencing, bail decisions, and eligibility for certain legal procedures. This provision, from Section 298 of the old CrPC, sets out reliable documentary methods, official court records or jail certificates, to prove someone's criminal history without needing to relitigate the entire earlier case from scratch.