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iso8583sim.security.pinblock For testing and simulation only. Real PIN handling happens inside an HSM, and clear PINs and keys must never pass through application code like this.

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Functions

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encode_pin_block()

Build a clear (unencrypted) 8-byte PIN block in format 0, 1 or 3. Parameters
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str
required
4 to 12 digit PIN
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str | None
default:"None"
Primary Account Number (required for formats 0 and 3)
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int
default:"0"
PIN block format: 0, 1 or 3
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bytes
The 8-byte clear PIN block

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decode_pin_block()

Recover the PIN from a clear 8-byte PIN block in format 0, 1 or 3.

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encrypt_pin_block()

Build an encrypted PIN block as it appears in field 52. Formats 0, 1 and 3 use a double or triple length TDES key and give 8 bytes. Format 4 uses an AES key and gives 16 bytes, which fits field 52 in the 1993 and 2003 versions. Parameters
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str
required
4 to 12 digit PIN
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str | None
required
Primary Account Number (not used by format 1)
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str | bytes
required
PIN encryption key as bytes or hex
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int
default:"0"
PIN block format: 0, 1, 3 or 4
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str
The encrypted PIN block as uppercase hex

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decrypt_pin_block()

Recover the PIN from an encrypted PIN block (formats 0, 1, 3 and 4). A wrong key is detected in every format, because it scrambles the whole block. A wrong PAN is always detected in format 4, but only sometimes in formats 0 and 3: there the PAN is applied with a single XOR, so a different PAN can still decode to a well-formed block with a different PIN. This is a property of those formats, not of this implementation. Raises
  • SecurityError: The block doesn’t decode to a valid PIN block