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RFC 7539, "ChaCha20 and Poly1305 for IETF Protocols", May 2015

Note: This RFC has been obsoleted by RFC 8439

Source of RFC: IRTF
See Also: RFC 7539w/ inline errata

Errata ID: 4858
Status: Verified
Type: Technical
Publication Format(s) : TEXT

Reported By: Timm Korte
Date Reported: 2016-11-10
Verifier Name: Lars Eggert
Date Verified: 2016-11-13

Section 2.8. says:

 1.  The amount of encrypted data possible in a single invocation is
     2^32-1 blocks of 64 bytes each, because of the size of the block
     counter field in the ChaCha20 block function.  This gives a total
     of 247,877,906,880 bytes, or nearly 256 GB.

It should say:

 1.  The amount of encrypted data possible in a single invocation is
     2^32-1 blocks of 64 bytes each, because of the size of the block
     counter field in the ChaCha20 block function.  This gives a total
     of 274,877,906,880 bytes, or nearly 256 GB.

Notes:

There is an error in the result of the P_MAX = ((2^32) - 1) * 64 calculation.
The correct value is 2_74_,877,906,880 while the document states 2_47_,877,906,880.
This error has already been adopted by multiple implementations as P_MAX value.

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