Code reviewHardcr-g031

Subject Crypto misuseLevel Senior–Staff~30 minCommon in Security interviewsIndustries Software development

Question

Review this Java field-encryption helper for PII.

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Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix — specific and kind.

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Code to reviewjava

1public byte[] encrypt(byte[] plaintext, SecretKey key) throws Exception {2    Cipher c = Cipher.getInstance("AES");      // provider default3    c.init(Cipher.ENCRYPT_MODE, key);4    return c.doFinal(plaintext);5}6 7public byte[] decrypt(byte[] ct, SecretKey key) throws Exception {8    Cipher c = Cipher.getInstance("AES");9    c.init(Cipher.DECRYPT_MODE, key);10    return c.doFinal(ct);11}

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