Legal references and standards
Every technical claim Probatio makes rests on a rule or a public standard. Here they all are, in the order in which they apply: Union law first, then Italian law, and finally the international technical standards.
Note. This page is a map of sources, not legal advice. Rules change; references must always be checked against the text in force. Wherever a guide on this site makes a legal claim, its precise source is here.
EU European Union
eIDAS — electronic identification and trust services for electronic transactions in the internal market
The parent regulation. Art. 3 (definitions), art. 22 (trusted lists), art. 25 (legal effects of signatures: § 2 gives a qualified signature «the equivalent legal effect of a handwritten signature»), art. 41 (§ 2 grants a qualified timestamp the presumption of accuracy of date and time and of integrity of the bound data).
eIDAS 2 — European digital identity framework (EUDI wallet)
In force since 20 May 2024, amending Regulation 910/2014. It does not change the rules on signatures and timestamps described in these guides, but introduces the European digital identity wallet and new trust services.
Formats of advanced electronic signatures and seals that public sector bodies must recognise
Adopted pursuant to arts. 27(5) and 37(5) of the eIDAS Regulation. Art. 1 requires public sector bodies that demand an advanced electronic signature, including one based on a qualified certificate, to recognise XAdES, CAdES and PAdES signatures at conformance levels B, T or LT, or the corresponding ASiC associated signature containers, provided they comply with the ETSI technical specifications listed in the Annex. The duty of recognition is therefore identical for every listed format.
Technical specifications for trusted lists
Defines how member states publish the list of qualified trust service providers required by eIDAS art. 22. It is the root of the trust chain Probatio reconstructs.
GDPR — protection of natural persons with regard to the processing of personal data
Relevant whenever an acquisition contains personal data. A non-obvious technical point: an RFC 3161 timestamp transmits only the digest to the TSA, never the document — so no personal data is disclosed to a third party.
IT Italy
Definitions
Before the rules on signatures and timestamps come the definitions: what, in law, the object being worked on is. The distinction between an electronic duplicate and an electronic copy, in particular, underpins the legal value of a forensic acquisition.
(ratificata con L. 48/2008)
Computer data
«Any representation of facts, information or concepts in a form suitable for processing in a computer system, including a program suitable to cause a computer system to perform a function.» It is the broadest definition in Italian law, and the one that matters in criminal proceedings: it covers the program, not merely the content.
Electronic document (documento informatico)
«The electronic document containing the computer representation of legally relevant acts, facts or data.» It dovetails with the notion of electronic document in eIDAS art. 3(35).
efficacia: art. 23-bis, c. 1
Electronic duplicate (duplicato informatico)
«The electronic document obtained by storing, on the same or a different medium, the same sequence of binary values as the original document.» Under art. 23-bis(1), electronic duplicates have the same legal value, for all purposes of law, as the document they are drawn from, if produced in accordance with the technical rules of art. 71. This is the category a bit-for-bit forensic copy falls into, and the reason why identity of the binary sequence — demonstrated by the digest — is legally decisive.
efficacia: art. 23-bis, c. 2
Electronic copy of an electronic document
«The electronic document having content identical to the one it is drawn from, on an electronic medium with a different sequence of binary values.» Anything but a theoretical distinction: a copy has the same content but a different digest, and its conformity to the original must be attested. A duplicate need not.
Personal data
«Any information relating to an identified or identifiable natural person.» A piece of computer data may simultaneously be personal data: the two qualifications overlap and answer to different bodies of law.
Sources
Italian Digital Administration Code
Art. 20(1-bis): a document signed with a digital, qualified or advanced electronic signature satisfies the written-form requirement and carries the effect of Civil Code art. 2702 — the advanced signature included. Use of a qualified or digital signature device is presumed attributable to its holder, absent proof to the contrary. Art. 24: digital signature.
Articles 1350, 2702, 2712
Art. 2702: evidentiary effect of a private deed — the effect CAD art. 20 refers to. Art. 1350, items 1-12: deeds requiring written form on pain of nullity; these need a qualified or digital signature, an advanced one is not enough. Art. 2712: effect of mechanical reproductions unless disavowed.
Ratification of the 2001 Budapest Convention on Cybercrime and adaptation of the Code of Criminal Procedure
It writes into criminal procedure the duty to adopt technical measures ensuring the preservation of original data and preventing its alteration: arts. 244(2), 247(1-bis), 254-bis, 260(2), 354(2) of the Code of Criminal Procedure. This is the legal basis of hashing and forensic imaging. Arts. 359 and 360 govern technical examinations, repeatable and not.
Technical rules on qualified certificates, signatures, seals and timestamps (determination 157/2020); guidelines on the electronic document
The technical source in force in Italy. AgID publishes and maintains the national trusted list, which feeds into the European one.
Equivalence of CAdES and PAdES digital signatures
The Joint Sections held that CAdES (.p7m) and PAdES (.pdf) signatures are both valid and equivalent, court e-filing included. No format is legally preferable: there is the one the recipient or the procedure requires.
Superseded rules, still often cited
They still turn up in reports and specifications. Citing them as law in force is a mistake: the matter is now governed by eIDAS, the CAD and the AgID guidelines.
- Deliberazione CNIPA 45/2009 — Technical rules on digital signature — superseded
- DPCM 22 febbraio 2013 — Technical rules on advanced, qualified and digital signatures — superseded
INT International standards
These documents are not law: they are the technical specifications the law refers to, which anyone may read and implement. That is why a case file produced with Probatio can be verified without Probatio.
RFCs — IETF
Time-Stamp Protocol (TSP)
The timestamping protocol: TimeStampReq, TimeStampToken, genTime, accuracy.
ESSCertIDv2 Update for RFC 3161
Update allowing SHA-2 based certificate identifiers inside timestamp tokens.
Cryptographic Message Syntax (CMS)
The envelope inside every .p7m, every PAdES and every .tsr. Successor to PKCS#7 (RFC 2315).
Internet X.509 Public Key Infrastructure — Certificate and CRL Profile
Certificate structure, extensions (keyUsage, AIA, QCStatements), chain building and validation.
Online Certificate Status Protocol (OCSP)
The revocation check Probatio performs. CRLs, provided for by RFC 5280, are not implemented.
PKCS #1 v2.2 — RSA Cryptography Specifications
RSA PKCS#1 v1.5 and RSA-PSS, the two RSA signature schemes verified.
Edwards-Curve Digital Signature Algorithm (EdDSA)
Ed25519: used to sign CERTO/LOCUS bundles and verified inside CMS envelopes.
The BagIt File Packaging Format (V1.0)
data/, manifest-<algo>.txt, tagmanifest-*, bag-info.txt, Payload-Oxum.
JSON Web Signature (JWS)
The basis of the JAdES profile.
The Base16, Base32, and Base64 Data Encodings
base64url, used in JWS tokens and XAdES digests.
MD5 Message-Digest Algorithm · US Secure Hash Algorithm 1 (SHA-1)
The algorithms stored inside E01 forensic images and found in historical hash sets.
Security considerations for MD5 and for SHA-1
The sources to cite when a report states that MD5 and SHA-1 do not resist collisions — and only collisions.
US Secure Hash Algorithms (SHA and SHA-based HMAC and HKDF)
The SHA-2 family.
The BLAKE2 Cryptographic Hash and MAC
BLAKE2b and BLAKE2s, among the twelve algorithms allowed in BagIt manifests.
ETSI
CAdES digital signatures — Building blocks and CAdES baseline signatures
Defines the baseline levels B-B, B-T, B-LT, B-LTA. The older -BES and -T labels come from TS 101 733.
PAdES digital signatures
Signature inside the PDF: /ByteRange, /Contents, incremental update. Its predecessor is TS 102 778.
XAdES digital signatures
XML signature, with the canonicalisation that makes it possible.
JAdES digital signatures
The AdES profile over JWS.
Associated Signature Containers (ASiC)
ZIP container of documents and signatures. Not supported by Probatio: an .asice must be unpacked first.
Procedures for Creation and Validation of AdES Digital Signatures
The source of the best-signature-time notion: the instant against which expiry and revocation are assessed.
Trusted Lists
Format of the trusted lists required by eIDAS art. 22.
Policy requirements for TSA providers · Timestamping protocol profile
What a qualified TSA must guarantee, and how it speaks.
NIST — FIPS and special publications
Secure Hash Standard (SHA-1, SHA-2)
The normative definition of SHA-1, SHA-224/256/384/512 and the truncated SHA-512/224 and SHA-512/256 variants.
SHA-3 Standard — Permutation-Based Hash and Extendable-Output Functions
The sponge construction (Keccak), structurally unlike SHA-2: this is what makes computing SHA-256 and SHA3-256 worthwhile.
Digital Signature Standard (DSS)
ECDSA and EdDSA, among the verified signature algorithms.
Guide to Integrating Forensic Techniques into Incident Response
Reference practice on acquisition, integrity and chain of custody.
ISO/IEC
Identification, collection, acquisition and preservation of digital evidence
The standard most frequently invoked by Italian case law on digital evidence.
Assuring suitability and adequacy of investigation methods
How to demonstrate the method used was fit for purpose.
Analysis and interpretation of digital evidence
How a technical indicator becomes a defensible conclusion.
Incident investigation principles and processes
The investigation lifecycle, from preparation to presentation.
W3C, OASIS, ontologies and practice
XML Signature Syntax and Processing · Canonical XML 1.0 · Exclusive C14N · XPath Filter 2.0
Canonicalisation, without which an XAdES signature would be desperately fragile: the same XML can be written in different yet logically identical ways.
Cryptographic Token Interface Standard
The interface through which software asks a smart card to sign a digest — C_Sign — without ever seeing the private key.
CSC API Specification
The remote-signing protocol: the key lives at the provider, and still only the digest travels.
Cyber-investigation Analysis Standard Expression · Unified Cyber Ontology
The JSON-LD ontology with which CERTO/LOCUS bundles formally describe what was acquired, when and with which tool.
Coalition for Content Provenance and Authenticity — Specification
The Content Credentials read during image analysis. They prove a provenance chain, not the truthfulness of the content.
US and European best practices for digital forensic examination
Practice, not law: useful to justify methodological choices in a report.
Expert Witness Compression Format
Not a public standard. The available documentation stems from the reverse-engineering work of the libewf project. Worth remembering before calling it a «standard format» in a report.
Scientific literature
How to Break MD5 and Other Hash Functions (EUROCRYPT)
The practical MD5 collision. A collision attack, not a preimage one.
The First Collision for Full SHA-1 (CRYPTO) — «SHAttered»
Two different PDFs with the same SHA-1 digest. Both crafted by the authors.
Identifying almost identical files using context triggered piecewise hashing (DFRWS)
The paper introducing ssdeep and CTPH.
Exposing Digital Forgeries from JPEG Ghosts (IEEE TIFS)
The JPEG ghost technique implemented in image analysis.
The guides explain how these standards translate into concrete operations: computing a battery of hashes, verifying a signature, reading a timestamp, validating a bag.