What encryption standards should be referenced when answering RFP security questions

When answering RFP security questions, reference AES-256 for data at rest, TLS 1.2 or 1.3 for data in transit, RSA-2048 or higher (or ECDSA) for key exchange, and FIPS 140-2/140-3 validated cryptographic modules. Cite the specific standard, key length, and validation status rather than vague phrases like "bank-grade encryption," which evaluators discount immediately.

The encryption standards evaluators expect to see

Most teams get this wrong by writing "we use strong encryption" with no specifics. Procurement security reviewers grade against a checklist. Name the algorithm, the key size, the protocol version, and where it applies. Here's the breakdown.

Data at rest

• AES-256 (Advanced Encryption Standard, 256-bit keys) is the default expectation. AES-128 is acceptable but AES-256 is what enterprise RFPs want to hear.
• Reference the NIST FIPS 197 specification that defines AES if the question asks for the governing standard.
• Note the implementation context: full-disk encryption, database-level (TDE), or field/column-level encryption. Specificity signals you actually do it.

Data in transit

• TLS 1.2 as a minimum, TLS 1.3 preferred. State that older protocols (SSL 3.0, TLS 1.0/1.1) are disabled.
• Mention cipher suite policy—forward secrecy via ECDHE, and rejection of weak ciphers like RC4 or 3DES.
• For internal service-to-service traffic, mention mTLS (mutual TLS) if applicable.

Key exchange and asymmetric crypto

• RSA-2048 minimum, RSA-4096 or ECDSA P-256/P-384 for higher assurance.
• Reference SHA-256 or higher for hashing and signatures. SHA-1 should be explicitly retired in your answer.

Validated modules

If you sell into government or regulated industries, FIPS 140-2 (legacy) or FIPS 140-3 validation of your cryptographic modules matters more than the algorithm itself. State the certificate number if you have one—it's verifiable on the NIST CMVP list.

A quick reference table

How to phrase the answer

Write answers that map directly to the question's compliance frame. A strong response reads:

"All customer data is encrypted at rest using AES-256 (FIPS 197) and in transit using TLS 1.3 with ECDHE key exchange and forward secrecy. Cryptographic operations run on FIPS 140-3 validated modules (CMVP cert #XXXX). Key management uses AWS KMS with annual rotation and HSM-backed root keys."

That sentence answers algorithm, protocol, validation, and key management in one pass. Tie encryption claims to your broader posture—the same evidence supports your SOC 2 compliance questionnaire responses and your ISO 27001 documentation requirements, so reuse vetted language across all three.

Don't forget key management

Encryption answers fall apart without key lifecycle detail. Reviewers want to know:

1. Where keys are stored — HSM, KMS, or software keystore.
2. Who can access them — separation of duties, no plaintext key exposure to staff.
3. Rotation policy — automated rotation cadence (e.g., annual or 90-day).
4. Envelope encryption — data keys wrapped by a master key.

Reference NIST SP 800-57 for key management lifecycle if the questionnaire goes deep.

Standards bodies worth naming

Citing the governing body adds credibility:

• NIST — FIPS 140-3, FIPS 197 (AES), SP 800 series. Browse the NIST cryptographic standards page for current guidance.
• IETF — TLS protocol RFCs (TLS 1.3 is RFC 8446).
• PCI SSC — PCI DSS encryption requirements if you handle cardholder data.
• ISO/IEC 27001 Annex A — controls A.8.24 covers cryptography.

Common mistakes to avoid

• Marketing language. "Military-grade" and "bank-level" mean nothing on a security scorecard.
• Outdated protocols. Claiming TLS support without specifying you've disabled TLS 1.0/1.1 is a red flag.
• Mismatched claims. If you say AES-256 here but your pentest summary or security certifications in your proposal contradict it, you lose trust. Keep encryption claims consistent across every artifact.
• No key management story. Strong encryption with weak key handling is a known gap reviewers probe.

Key takeaways

• Always cite specific algorithms and key lengths: AES-256, TLS 1.3, RSA-2048+, SHA-256.
• Reference FIPS 140-2/140-3 validation and CMVP certificate numbers for regulated buyers.
• Pair encryption claims with a key management narrative covering storage, rotation, and access control.
• Map answers to NIST, IETF, and ISO standards by name to signal rigor.
• Keep claims consistent across your security questionnaire, compliance attestations, and certifications.