No, perhaps it would be better phrased as this: Bitcoin does not meet the minimum standard of security required by modern cryptography despite being built on s

No, perhaps it would be better phrased as this: Bitcoin does not meet the minimum standard of security required by modern cryptography despite being built on systems that do meet such a standard. Even that phrasing is suboptimal, though, since the definition of "security" for a hash function is different from the definition for a signature system and both are different from the definition used for digital cash.