Add ARelaxCostRestriction parameter to Scrypt#41
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Xor-el merged 1 commit intoMar 19, 2026
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Add ARelaxCostRestriction parameter to Scrypt to allow N >= 65536 when r = 1 The RFC 7914 constraint N < 2^(128*r/8) was confirmed by Colin Percival (Scrypt creator and RFC co-author) to be an accidental error in the RFC. The intended bound was N < 2^(128*r*8), which is trivially satisfied. RFC errata 5971, 5972, 5973 have been filed. The Ethereum Web3 Secret Storage standard uses N=262144, r=1, p=8 as its default Scrypt parameters. These are widely used in practice (geth, web3.py, web3.js, etc.) and accepted by the Scrypt reference implementation (Tarsnap) and Go's x/crypto/scrypt, but were rejected by the existing validation. A new ARelaxCostRestriction default parameter (False) is added to ValidatePBKDF_ScryptInputs, the constructor, and CreatePBKDF_Scrypt. When True, the erroneous cost/blocksize check is skipped. Existing callers are unaffected. See: golang/go#33703 (comment)
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Add ARelaxCostRestriction parameter to Scrypt to allow N >= 65536 when r = 1
The RFC 7914 constraint N < 2^(128r/8) was confirmed by Colin Percival (Scrypt creator and RFC co-author) to be an accidental error in the RFC. The intended bound was N < 2^(128r*8), which is trivially satisfied. RFC errata 5971, 5972, 5973 have been filed.
The Ethereum Web3 Secret Storage standard uses N=262144, r=1, p=8 as its default Scrypt parameters. These are widely used in practice (geth, web3.py, web3.js, etc.) and accepted by the Scrypt reference implementation (Tarsnap) and Go's x/crypto/scrypt, but were rejected by the existing validation.
A new ARelaxCostRestriction default parameter (False) is added to ValidatePBKDF_ScryptInputs, the constructor, and CreatePBKDF_Scrypt. When True, the erroneous cost/blocksize check is skipped. Existing callers are unaffected.
See: golang/go#33703 (comment)