10 lines
604 B
Text
10 lines
604 B
Text
Security
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* Fix a security reduction in CTR_DRBG when the initial seeding obtained a
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nonce from entropy. Applications were affected if they called
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mbedtls_ctr_drbg_set_nonce_len(), if they called
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mbedtls_ctr_drbg_set_entropy_len() with a size that was 3/2 times the key
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length, or when the entropy module uses SHA-256 and CTR_DRBG uses AES-256.
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In such cases, a random nonce was necessary to achieve the advertised
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security strength, but the code incorrectly used a constant instead of
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entropy from the nonce.
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Found by John Stroebel in #3819 and fixed in #3973.
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