Hawkynt

ISO/IEC 7816-4

ISO/IEC 7816-4 padding scheme appends a single ‘1’ bit (0x80 byte) followed by zero bits to fill the block. This method is designed for smart card communication and provides unambiguous padding removal. It is identical to bit padding and is widely used in cryptographic protocols.

Properties

Property	Value
Category	Padding Schemes
Sub-category	Smart Card Padding
Security status	🛡️ Secure
Complexity	Not specified
Inventor	ISO/IEC
Year	2005
Origin	Not specified
Source	algorithms/padding/iso7816-4.js

Capabilities

Flag	Value
IsLengthIncluded	No

Security

Status: 🛡️ Secure

Known vulnerabilities

Issue	Description	Mitigation
None Known	ISO/IEC 7816-4 padding provides unambiguous padding removal with no known cryptographic weaknesses.	—
Length Expansion	Always adds at least one byte of padding, which increases data size even for complete blocks.	—

Documentation

• ISO/IEC 7816-4 Standard
• Smart Card Communication
• Padding in Cryptography

References

• ISO/IEC 7816 Series
• Smart Card Standards
• Cryptographic Padding Methods

Test vectors

3 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — ISO 7816-4 padding with 17 bytes needed

Source: ISO/IEC 7816-4

Field	Value
blockSize	32
input	6bc1bee22e409f96e93d7e11739317
expected	6bc1bee22e409f96e93d7e117393178000000000000000000000000000000000

Vector 2 — ISO 7816-4 padding for half block

Source: ISO/IEC 7816-4

Field	Value
blockSize	32
input	6bc1bee22e409f96e93d7e117393172a
expected	6bc1bee22e409f96e93d7e117393172a80000000000000000000000000000000

Vector 3 — ISO 7816-4 padding with 3 bytes needed

Source: ISO/IEC 7816-4

Field	Value
blockSize	8
input	6bc1bee22e
expected	6bc1bee22e800000

---

← All algorithms

This site is open source. Improve this page.