Hash Migration Tool

How to Use the Hash Migration Tool

1. Pick a sample record. Choose a few real inputs from the system you are migrating (a document, an API payload, a checksum target).
2. Compute all digests. Confirm the MD5 or SHA-1 value matches what you have stored. That proves you are hashing exactly the same bytes (encoding, trailing newlines and whitespace all matter).
3. Record the SHA-224 value. This is what your migrated code path must produce for the same input.
4. Verify the new system. Paste the SHA-224 your application generated into the verify box. A match confirms the implementation; a mismatch usually points to an encoding or padding difference.
5. Roll out with dual hashing. Store both digests during the transition, then retire the old column once every record has a SHA-224 value. The SHA-224 migration guide covers the full rollout and rollback plan.

What Changes When You Migrate

Dual-Hash Code for the Transition Period

During migration, compute the legacy digest and SHA-224 together so existing lookups keep working while new records are written with the new algorithm.

import hashlib

def dual_hash(data: bytes) -> dict:
    """Return the legacy digest and the SHA-224 digest for the same bytes."""
    return {
        "legacy_sha1": hashlib.sha1(data).hexdigest(),   # keep until migration completes
        "sha224": hashlib.sha224(data).hexdigest(),      # new canonical value
    }

print(dual_hash(b"abc"))
# {'legacy_sha1': 'a9993e364706816aba3e25717850c26c9cd0d89d',
#  'sha224': '23097d223405d8228642a477bda255b32aadbce4bda0b3f7e36c9da7'}

const { createHash } = require('crypto');

function dualHash(buffer) {
  return {
    legacyMd5: createHash('md5').update(buffer).digest('hex'),   // keep until migration completes
    sha224:    createHash('sha224').update(buffer).digest('hex') // new canonical value
  };
}

console.log(dualHash(Buffer.from('abc')));
// { legacyMd5: '900150983cd24fb0d6963f7d28e17f72',
//   sha224: '23097d223405d8228642a477bda255b32aadbce4bda0b3f7e36c9da7' }

# Compare digests for a file before and after migration
openssl dgst -sha1   firmware.bin
openssl dgst -sha224 firmware.bin

Hash Migration Questions

Can I convert an existing MD5 or SHA-1 hash directly into SHA-224?

No. Hash functions are one-way, so there is no way to derive a SHA-224 value from an MD5 or SHA-1 digest. You must re-hash the original data. For files and records that is straightforward; for password hashes it means re-hashing on the user's next successful login (and, for passwords, using a slow KDF such as Argon2 or PBKDF2 rather than a bare hash).

Why do my SHA-224 values differ from this tool?

Almost always an input difference: UTF-8 versus UTF-16 encoding, a trailing newline added by a shell, or hex versus raw bytes. Hash the sample here, compare the MD5 line with your stored value first, and adjust until the legacy digest matches; the SHA-224 value will then match too. The NIST SHA-224 test vectors are a good sanity check for the implementation itself.

Should I migrate to SHA-224 or SHA-256?

Both are secure SHA-2 members. SHA-224 is the right target when storage, bandwidth or a fixed 112-bit security level matters (embedded devices, compact tokens, legacy field widths). If none of those apply, SHA-256 offers broader ecosystem support. The SHA-224 vs SHA-256 guide walks through the decision.

Related Tools and Guides

• SHA-224 Migration Guide: step-by-step plan for MD5, SHA-1 and SHA-256 migrations with rollback strategy
• SHA-224 Hash Calculator: compute and verify individual SHA-224 hashes for text or files
• Hash Algorithm Comparison Tool: performance and output comparison across SHA-2, SHA-3 and BLAKE2
• Common SHA-224 Implementation Mistakes: the errors that cause mismatched digests