import base64
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.primitives.asymmetric.utils import decode_dss_signature
from cryptography.hazmat.primitives.serialization import load_der_public_key
from cryptography.hazmat.backends import default_backend
from cryptography.exceptions import InvalidSignature

def verify_signature(public_key_base64: str, digest_algorithm: str, base64_data: str, base64_signature: str) -> bool:
    # Decode the base64 encoded public key, data, and signature
    public_key_der = base64.b64decode(public_key_base64)
    data = base64.b64decode(base64_data)
    signature = base64.b64decode(base64_signature)
    
    # Load the public key from the raw DER-encoded bytes
    public_key = load_der_public_key(public_key_der, backend=default_backend())
    
    # Select the digest algorithm
    if digest_algorithm.lower() == 'sha256':
        chosen_hash = hashes.SHA256()
    elif digest_algorithm.lower() == 'sha384':
        chosen_hash = hashes.SHA384()
    elif digest_algorithm.lower() == 'sha512':
        chosen_hash = hashes.SHA512()
    else:
        raise ValueError("Unsupported digest algorithm")

    try:
        # Verify the signature
        public_key.verify(signature, data, ec.ECDSA(chosen_hash))
        return True
    except InvalidSignature:
        return False

public_key_base64 = 'MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEbfwR+RJudXscgRBRpKX1XFDy3PyudDxz/SfnRi1fT8ekpfBd2O1uoz7jr3Z8nKzxA69EUQ+eFCFI3zeubPWU7w=='
digest_algorithm = "SHA256"
base64_data = "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"
base64_signature = "MEUCIQC57LC1KG/uog1EKkCdqMUmC9audrMR1x+s7/HH/JPIXAIgTjXlXWKaGoT5qIXnYh2bOvntjn/9AmBnkTm9p2TF59A="

# Example usage
#public_key_base64 = "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE1YrO4tKt3O1db58LJ/FLj5iv9JfrZp2k/udEjO5AAwUIJTeBvlvOKx3JX/gT6DtjHtAEoL3UNtBt7oO/SFZ4gg=="
#digest_algorithm = "SHA256"
#base64_data = "SGVsbG8gd29ybGQ="  # "Hello world" in base64
#base64_signature = "MEUCIQC1clZrhDxeFVNCqxGFkEjVR8zSlDA5FcOtd5v+ctXt2wIgfZ5PHzkm9UpyXyo6ns/n1hzK1aTz9+yKMdX1FMyEYPg="

is_valid = verify_signature(public_key_base64, digest_algorithm, base64_data, base64_signature)
print(f"Signature valid: {is_valid}")