Section 78 governs the proof of public documents through prescribed official records, certified copies, and authorised publications. Governmental acts, orders, notifications, legislative proceedings, and municipal proceedings may be proved through specified departmental records, journals, certified copies, or official publications. Foreign executive and legislative records may be proved through authorised or accepted journals, sealed copies, or statutory recognition. Other foreign public documents require the original or a certified copy, authenticated through notarial, consular, or diplomatic certification and supported by proof of their character under foreign law.

Bank deposits linked to a second PAN require correlation with audited books of account, income-tax returns, and business records maintained under the original PAN before they are treated as unexplained money. The existence of a second PAN does not remove the need to verify whether the deposits and related transactions were already recorded under the original PAN. Verification should also cover the circumstances in which the second PAN was issued and cancelled. Where such verification has not occurred, reassessment after examination of the records and a reasonable opportunity to furnish evidence is required.

Composite sampling of separately seized packets requires recorded verification that the packages match in size, weight, markings and colour-test results, with equal quantities drawn from each. Mixing packet contents without that verification may fail substantial compliance with sampling directions and make samples unreliable representatives of the seized bulk. Sampling defects are assessed for prejudice rather than treated as automatically fatal. Where delayed laboratory dispatch compounds uncertainty over liability for alleged contraband, and the applicant is unlikely to reoffend, reasonable grounds may satisfy statutory bail conditions despite restrictions applicable to commercial-quantity allegations.

Input tax credit on debit notes availed on or after 1 January 2021 is determined by the financial year of the debit note, not that of the underlying invoice. A physical invoice need not accompany goods moved under an e-invoice where the QR code containing the Invoice Reference Number is electronically produced for verification. Refund of accumulated unutilized ITC on exports is restricted only where export duty is actually payable; nil-rated, exempt, or non-scheduled goods are not treated as subjected to export duty.

Cash-deposit addition for unexplained money under Section 69A read with Section 115BBE cannot be assessed in a dissolved partnership firm's hands when the relevant bank account is owned and operated by an individual proprietor. Where the proprietor acknowledges the account and reports its transactions in her income-tax return, assessment must be directed to the appropriate person, subject to law.

Proof of public documents may be made by producing certified copies that purport to reproduce the contents of the relevant public document or any part of it. Such certified copies serve as proof of the contents represented in them.

Certified copies of public documents must be supplied by a public officer having custody of a document that a person is entitled to inspect, on demand and payment of legally prescribed fees. Each copy must include a dated certificate confirming it is a true copy, signed by the responsible officer with the officer's official title and sealed where authorised. An officer ordinarily authorised to deliver such copies is deemed to have custody of the document.

Private documents are defined through a residual classification: every document that does not qualify as a public document falls within the category of private documents. Public-document status is the determining exclusion; absent that status, a document is treated as private under the evidentiary classification. The classification therefore creates a default category for non-public documents.

Section 74 classifies public documents as documents forming acts, or records of acts, of sovereign authority, official bodies and tribunals, and public officers exercising legislative, judicial, or executive functions in India, the Commonwealth, or foreign countries. It also includes public records kept in any State of private documents.

Proof of a digital signature may be established by requiring production of the relevant Digital Signature Certificate from the purported signatory, the Controller, or the Certifying Authority. The Court may also direct another person to apply the public key listed in that certificate to verify whether the digital signature was affixed by the person it purports to identify.

Section 73 permits comparison of signatures, writings and seals to determine whether a disputed mark was made by the person it purports to identify. A signature, writing or seal admitted or proved to the Court's satisfaction may be used as the comparison standard. The Court may require a person present to provide words or figures for comparison. The mechanism extends to finger-impressions.

Proof of an attested document not required by law to be attested is governed by the rules applicable to an unattested document. The fact that the document bears attestation does not itself attract the evidentiary mode prescribed for documents whose attestation is legally mandatory.

Proof of execution may be established by other evidence where an attesting witness denies the execution of the document or does not recollect it. Other evidence remains available to prove execution when the witness either disputes that the document was executed or cannot remember the execution, so the denial or lack of recollection does not prevent proof through evidentiary material independent of the witness's recollection.

Admission of execution by a party to an attested document is sufficient proof of its execution against that party. This applies even where the law requires the document to be attested, dispensing with further proof of execution against the party making the admission.

Where no attesting witness can be found, proof requires evidence that at least one witness's attestation is in that witness's handwriting and that the executant's signature is in the executant's handwriting. The same requirements apply where the document purports to have been executed in the United Kingdom.

Section 68 requires proof of execution before a document legally required to be attested may be used as evidence. At least one attesting witness must be called where the witness is alive, subject to the court's process, and capable of giving evidence. For registered documents other than wills, this requirement does not apply unless execution is specifically denied by the purported executant.

Section 67A requires proof that an alleged electronic signature affixed to an electronic record belongs to the stated subscriber, except where it is a secure electronic signature. It establishes an evidentiary authentication requirement for ordinary electronic signatures while preserving distinct treatment for secure electronic signatures.

Section 67 requires proof of a person's signature or handwriting where a document is alleged to have been signed or written, wholly or partly, by that person. The party relying on the allegation must establish that the disputed signature or relevant handwriting is genuinely attributable to the alleged signer or writer.

Secondary evidence of a document's contents generally requires prior notice to produce the original to the party having possession or power over it, or to that party's attorney or pleader. Where no notice is legally prescribed, the Court may require reasonable notice. Notice may be dispensed with where the document is itself a notice, production is evidently required, the original was obtained by fraud or force, is in Court, its loss is admitted, or its holder is beyond the Court's process.

Revisionary jurisdiction under section 263 requires an assessment order to be both erroneous and prejudicial to the interests of the Revenue. Cash deposits attributed to an individual were supported by a bank certificate showing incorrect PAN updating and were considered in the charitable trust's assessment, including an addition for the same cash. Non-addition in the individual's assessment was therefore justified, so the conditions for revision were not met and the revision order was set aside.