ASN.1 Noir Parser — Parsing X.509 & DER Structures in Noir

[sanjay-sol]

ASN.1 Noir Parser

👉 You can find complete implementation details here - Github Repository

A fully functional ASN.1 parser written in Noir for use in zero-knowledge circuits. This parser decodes DER-encoded binary structures such as X.509 certificates and extracts components like OIDs, UTF8 strings, UTC times, bit strings, octet strings, and signatures.

Built for ZK use-cases such as proving certificate validity without revealing the entire document.

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Use Cases

These circuits enable ZK applications like:

• Proving a certificate contains a specific issuer
• Verifying a signature algorithm used is a valid OID
• Showing date ranges (validity period) without exposing exact timestamps
• Extracting organization or country from certificates in zero-knowledge

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Features

• Built entirely in Noir
• Works with ASN.1 DER structures
• Type-Length-Value (TLV) parser circuit
• Extracts:
  • UTF8String
  • UTCTime
  • Object Identifiers (OIDs)
  • Bit Strings
  • Octet Strings
  • Signature & Integer Values
  • ...and more

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Test Coverage

Run tests using:

nargo test

Test cases coverage

[asn] Running 53 test functions
[asn] Testing test_main ... ok
[asn] Testing parser::test_decode_tlv_long_form ... ok
[asn] Testing parser::test_decode_tlv_nested_tlv_inside_sequence ... ok
[asn] Testing parser::test_decode_tlv_short_form ... ok
[asn] Testing parser::test_algorithm_identifier_oid_only ... ok
[asn] Testing parser::test_algorithm_identifier_truncated_oid ... ok
[asn] Testing parser::test_algorithm_identifier_sha256_with_rsa ... ok
[asn] Testing parser::test_all_ones_unused_zero ... ok
[asn] Testing parser::test_algorithm_identifier_sha1_with_rsa ... ok
[asn] Testing parser::test_empty_bit_string ... ok
[asn] Testing parser::test_all_ones_unused_zero_with_tlv ... ok
[asn] Testing parser::test_empty_bit_string_with_tlv ... ok
[asn] Testing parser::test_multiple_bytes_with_unused ... ok
[asn] Testing parser::test_no_unused_bits_mixed_bits ... ok
[asn] Testing parser::test_no_unused_bits_full_byte ... ok
[asn] Testing parser::test_parse_algorithm_identifier_sha256_rsa ... ok
[asn] Testing parser::test_multiple_bytes_with_unused_with_tlv ... ok
[asn] Testing parser::test_no_unused_bits_full_byte_with_tlv ... ok
[asn] Testing parser::test_parse_attribute_common_name ... ok
[asn] Testing parser::test_parse_integer ... ok
[asn] Testing parser::test_parse_integer_empty ... ok
[asn] Testing parser::test_parse_common_name ... ok
[asn] Testing parser::test_parse_integer_max_8_bytes ... ok
[asn] Testing parser::test_no_unused_bits_mixed_bits_with_tlv ... ok
[asn] Testing parser::test_parse_integer_neg1 ... ok
[asn] Testing parser::test_parse_integer_negative_8_bytes ... ok
[asn] Testing parser::test_parse_integer_negative_multi_byte ... ok
[asn] Testing parser::test_parse_integer_positive_multi_byte ... ok
[asn] Testing parser::test_parse_integer_positive_single_byte ... ok
[asn] Testing parser::test_parse_integer_zero ... ok
[asn] Testing parser::test_parse_octet_string_all_ff ... ok
[asn] Testing parser::test_parse_octet_string_all_zero ... ok
[asn] Testing parser::test_parse_octet_string_empty ... ok
[asn] Testing parser::test_parse_octet_string_mixed_bytes ... ok
[asn] Testing parser::test_parse_country_name ... ok
[asn] Testing parser::test_parse_octet_string_single_byte ... ok
[asn] Testing parser::test_parse_jurisdiction_country ... ok
[asn] Testing parser::test_parse_oid_ec_public_key ... ok
[asn] Testing parser::test_parse_oid_common_name ... ok
[asn] Testing parser::test_parse_oid_enterprise ... ok
[asn] Testing parser::test_parse_validity_diff_times ... ok
[asn] Testing parser::test_parse_oid_minimal ... ok
[asn] Testing parser::test_parse_oid_rsa_encryption ... ok
[asn] Testing parser::test_parse_validity_future_date ... ok
[asn] Testing parser::test_parse_organization_name ... ok
[asn] Testing parser::test_parse_validity_min_date ... ok
[asn] Testing parser::test_parse_validity_utctime ... ok
[asn] Testing parser::test_with_unused_bits_at_end ... ok
[asn] Testing parser::test_with_unused_bits_at_end_with_tlv ... ok

Resources

• ASN.1 TLV Format – RFC 5280
• OID Reference – oid-info.com
• ASN.1 Playground – lapo.it/asn1js

Built With

• Noir
• Nargo

[Savio-Sou]

Thanks for sharing the work! Curious are you building something off of it? 👀